复制代码fun.call(thisArg, arg1, arg2, ...)

复制代码func.apply(thisArg, [argsArray])

复制代码// 例子1：浏览器环境 非严格模式下
var doSth = function(a, b){
    console.log(this);
    console.log([a, b]);
}
doSth.apply(null, [1, 2]); // this是window  // [1, 2]
doSth.apply(0, [1, 2]); // this 是 Number(0) // [1, 2]
doSth.apply(true); // this 是 Boolean(true) // [undefined, undefined]
doSth.call(undefined, 1, 2); // this 是 window // [1, 2]
doSth.call('0', 1, {a: 1}); // this 是 String('0') // [1, {a: 1}]

复制代码// 例子2：浏览器环境 严格模式下
'use strict';
var doSth2 = function(a, b){
    console.log(this);
    console.log([a, b]);
}
doSth2.call(0, 1, 2); // this 是 0 // [1, 2]
doSth2.apply('1'); // this 是 '1' // [undefined, undefined]
doSth2.apply(null, [1, 2]); // this 是 null // [1, 2]

复制代码// 浏览器环境 非严格模式下
var doSth = function(a, b){
    console.log(this);
    console.log(this.name);
    console.log([a, b]);
}
var student = {
    name: '若川',
    doSth: doSth,
};
student.doSth(1, 2); // this === student // true // '若川' // [1, 2]
doSth.apply(student, [1, 2]); // this === student // true // '若川' // [1, 2]

复制代码// 浏览器环境 非严格模式
function getGlobalObject(){
    return this;
}
Function.prototype.applyFn = function apply(thisArg, argsArray){ // `apply` 方法的 `length` 属性是 `2`。
    // 1.如果 `IsCallable(func)` 是 `false`, 则抛出一个 `TypeError` 异常。
    if(typeof this !== 'function'){
        throw new TypeError(this + ' is not a function');
    }

    // 2.如果 argArray 是 null 或 undefined, 则
    // 返回提供 thisArg 作为 this 值并以空参数列表调用 func 的 [[Call]] 内部方法的结果。
    if(typeof argsArray === 'undefined' || argsArray === null){
        argsArray = [];
    }
    
    // 3.如果 Type(argArray) 不是 Object, 则抛出一个 TypeError 异常 .
    if(argsArray !== new Object(argsArray)){
        throw new TypeError('CreateListFromArrayLike called on non-object');
    }

    if(typeof thisArg === 'undefined' || thisArg === null){
        // 在外面传入的 thisArg 值会修改并成为 this 值。
        // ES3: thisArg 是 undefined 或 null 时它会被替换成全局对象 浏览器里是window
        thisArg = getGlobalObject();
    }

    // ES3: 所有其他值会被应用 ToObject 并将结果作为 this 值，这是第三版引入的更改。
    thisArg = new Object(thisArg);
    var __fn = '__fn';
    thisArg[__fn] = this;
    // 9.提供 thisArg 作为 this 值并以 argList 作为参数列表，调用 func 的 [[Call]] 内部方法，返回结果
    var result = thisArg[__fn](...argsArray);
    delete thisArg[__fn];
    return result;
};

复制代码// 生成UUID 通用唯一识别码
// 大概生成 这样一串 '18efca2d-6e25-42bf-a636-30b8f9f2de09'
function generateUUID(){
    var i, random;
    var uuid = '';
    for (i = 0; i < 32; i++) {
        random = Math.random() * 16 | 0;
        if (i === 8 || i === 12 || i === 16 || i === 20) {
            uuid += '-';
        }
        uuid += (i === 12 ? 4 : (i === 16 ? (random & 3 | 8) : random))
            .toString(16);
    }
    return uuid;
}
// 简单实现
// '__' + new Date().getTime();

复制代码var student = {
    name: '若川',
    doSth: 'doSth',
};
var originalVal = student.doSth;
var hasOriginalVal = student.hasOwnProperty('doSth');
student.doSth = function(){};
delete student.doSth;
// 如果没有，`originalVal`则为undefined，直接赋值新增了一个undefined，这是不对的，所以需判断一下。
if(hasOriginalVal){
    student.doSth = originalVal;
}
console.log('student:', student); // { name: '若川', doSth: 'doSth' }

复制代码eval(string)

复制代码new Function ([arg1[, arg2[, ...argN]],] functionBody)

复制代码简单例子：
var sum = new Function('a', 'b', 'return a + b');
console.log(sum(2, 6));

复制代码// 稍微复杂点的例子：
var student = {
    name: '若川',
    doSth: function(argsArray){
        console.log(argsArray);
        console.log(this.name);
    }
};
// var result = student.doSth(['Rowboat', 18]);
// 用new Function()生成函数并执行返回结果
var result = new Function('return arguments[0][arguments[1]](arguments[2][0], arguments[2][1])')(student, 'doSth', ['Rowboat', 18]);
// 个数不定
// 所以可以写一个函数生成函数代码：
function generateFunctionCode(argsArrayLength){
    var code = 'return arguments[0][arguments[1]](';
    for(var i = 0; i < argsArrayLength; i++){
        if(i > 0){
            code += ',';
        }
        code += 'arguments[2][' + i + ']';
    }
    code += ')';
    // return arguments[0][arguments[1]](arg1, arg2, arg3...)
    return code;
}

复制代码function test(){
    var undefined = 3;
    console.log(undefined); // chrome下也是 3
}
test();

复制代码// 浏览器环境 非严格模式
function getGlobalObject(){
    return this;
}
function generateFunctionCode(argsArrayLength){
    var code = 'return arguments[0][arguments[1]](';
    for(var i = 0; i < argsArrayLength; i++){
        if(i > 0){
            code += ',';
        }
        code += 'arguments[2][' + i + ']';
    }
    code += ')';
    // return arguments[0][arguments[1]](arg1, arg2, arg3...)
    return code;
}
Function.prototype.applyFn = function apply(thisArg, argsArray){ // `apply` 方法的 `length` 属性是 `2`。
    // 1.如果 `IsCallable(func)` 是 `false`, 则抛出一个 `TypeError` 异常。
    if(typeof this !== 'function'){
        throw new TypeError(this + ' is not a function');
    }
    // 2.如果 argArray 是 null 或 undefined, 则
    // 返回提供 thisArg 作为 this 值并以空参数列表调用 func 的 [[Call]] 内部方法的结果。
    if(typeof argsArray === 'undefined' || argsArray === null){
        argsArray = [];
    }
    // 3.如果 Type(argArray) 不是 Object, 则抛出一个 TypeError 异常 .
    if(argsArray !== new Object(argsArray)){
        throw new TypeError('CreateListFromArrayLike called on non-object');
    }
    if(typeof thisArg === 'undefined' || thisArg === null){
        // 在外面传入的 thisArg 值会修改并成为 this 值。
        // ES3: thisArg 是 undefined 或 null 时它会被替换成全局对象 浏览器里是window
        thisArg = getGlobalObject();
    }
    // ES3: 所有其他值会被应用 ToObject 并将结果作为 this 值，这是第三版引入的更改。
    thisArg = new Object(thisArg);
    var __fn = '__' + new Date().getTime();
    // 万一还是有 先存储一份，删除后，再恢复该值
    var originalVal = thisArg[__fn];
    // 是否有原始值
    var hasOriginalVal = thisArg.hasOwnProperty(__fn);
    thisArg[__fn] = this;
    // 9.提供 `thisArg` 作为 `this` 值并以 `argList` 作为参数列表，调用 `func` 的 `[[Call]]` 内部方法，返回结果。
    // ES6版
    // var result = thisArg[__fn](...args);
    var code = generateFunctionCode(argsArray.length);
    var result = (new Function(code))(thisArg, __fn, argsArray);
    delete thisArg[__fn];
    if(hasOriginalVal){
        thisArg[__fn] = originalVal;
    }
    return result;
};

复制代码Function.prototype.callFn = function call(thisArg){
    var argsArray = [];
    var argumentsLength = arguments.length;
    for(var i = 0; i < argumentsLength - 1; i++){
        // argsArray.push(arguments[i + 1]);
        argsArray[i] = arguments[i + 1];
    }
    console.log('argsArray:', argsArray);
    return this.applyFn(thisArg, argsArray);
}
// 测试例子
var doSth = function (name, age){
    var type = Object.prototype.toString.call(this);
    console.log(typeof doSth);
    console.log(this === firstArg);
    console.log('type:', type);
    console.log('this:', this);
    console.log('args:', [name, age], arguments);
    return 'this--';
};

var name = 'window';

var student = {
    name: '若川',
    age: 18,
    doSth: 'doSth',
    __fn: 'doSth',
};
var firstArg = student;
var result = doSth.applyFn(firstArg, [1, {name: 'Rowboat'}]);
var result2 = doSth.callFn(firstArg, 1, {name: 'Rowboat'});
console.log('result:', result);
console.log('result2:', result2);

复制代码// 看看V8引擎中的具体实现：
function ArrayPush() {
    var n = TO_UINT32( this.length );    // 被push的对象的length
    var m = %_ArgumentsLength();     // push的参数个数
    for (var i = 0; i < m; i++) {
        this[ i + n ] = %_Arguments( i );   // 复制元素     (1)
    }
    this.length = n + m;      // 修正length属性的值    (2)
    return this.length;
};

复制代码// 最终版版 删除注释版，详细注释看文章
// 浏览器环境 非严格模式
function getGlobalObject(){
    return this;
}
function generateFunctionCode(argsArrayLength){
    var code = 'return arguments[0][arguments[1]](';
    for(var i = 0; i < argsArrayLength; i++){
        if(i > 0){
            code += ',';
        }
        code += 'arguments[2][' + i + ']';
    }
    code += ')';
    return code;
}
Function.prototype.applyFn = function apply(thisArg, argsArray){
    if(typeof this !== 'function'){
        throw new TypeError(this + ' is not a function');
    }
    if(typeof argsArray === 'undefined' || argsArray === null){
        argsArray = [];
    }
    if(argsArray !== new Object(argsArray)){
        throw new TypeError('CreateListFromArrayLike called on non-object');
    }
    if(typeof thisArg === 'undefined' || thisArg === null){
        thisArg = getGlobalObject();
    }
    thisArg = new Object(thisArg);
    var __fn = '__' + new Date().getTime();
    var originalVal = thisArg[__fn];
    var hasOriginalVal = thisArg.hasOwnProperty(__fn);
    thisArg[__fn] = this;
    var code = generateFunctionCode(argsArray.length);
    var result = (new Function(code))(thisArg, __fn, argsArray);
    delete thisArg[__fn];
    if(hasOriginalVal){
        thisArg[__fn] = originalVal;
    }
    return result;
};
Function.prototype.callFn = function call(thisArg){
    var argsArray = [];
    var argumentsLength = arguments.length;
    for(var i = 0; i < argumentsLength - 1; i++){
        argsArray[i] = arguments[i + 1];
    }
    return this.applyFn(thisArg, argsArray);
}

复制代码import React, { Component } from 'react';
class TodoItem extends Component{
    constructor(props){
        super(props);
        this.handleClick = this.handleClick.bind(this);
    }
    handleClick(){
        console.log('handleClick');
    }
    render(){
        return  (
            <div onClick={this.handleClick}>点击</div>
        );
    };
}
export default TodoItem;

复制代码var obj = {};
console.log(obj);
console.log(typeof Function.prototype.bind); // function
console.log(typeof Function.prototype.bind());  // function
console.log(Function.prototype.bind.name);  // bind
console.log(Function.prototype.bind().name);  // bound

复制代码var obj = {
    name: '若川',
};
function original(a, b){
    console.log(this.name);
    console.log([a, b]);
    return false;
}
var bound = original.bind(obj, 1);
var boundResult = bound(2); // '若川', [1, 2]
console.log(boundResult); // false
console.log(original.bind.name); // 'bind'
console.log(original.bind.length); // 1
console.log(original.bind().length); // 2 返回original函数的形参个数
console.log(bound.name); // 'bound original'
console.log((function(){}).bind().name); // 'bound '
console.log((function(){}).bind().length); // 0

复制代码// 第一版 修改this指向，合并参数
Function.prototype.bindFn = function bind(thisArg){
    if(typeof this !== 'function'){
        throw new TypeError(this + 'must be a function');
    }
    // 存储函数本身
    var self = this;
    // 去除thisArg的其他参数 转成数组
    var args = [].slice.call(arguments, 1);
    var bound = function(){
        // bind返回的函数 的参数转成数组
        var boundArgs = [].slice.call(arguments);
        // apply修改this指向，把两个函数的参数合并传给self函数，并执行self函数，返回执行结果
        return self.apply(thisArg, args.concat(boundArgs));
    }
    return bound;
}
// 测试
var obj = {
    name: '若川',
};
function original(a, b){
    console.log(this.name);
    console.log([a, b]);
}
var bound = original.bindFn(obj, 1);
bound(2); // '若川', [1, 2]

复制代码var obj = {
    name: '若川',
};
function original(a, b){
    console.log('this', this); // original {}
    console.log('typeof this', typeof this); // object
    this.name = b;
    console.log('name', this.name); // 2
    console.log('this', this);  // original {name: 2}
    console.log([a, b]); // 1, 2
}
var bound = original.bind(obj, 1);
var newBoundResult = new bound(2);
console.log(newBoundResult, 'newBoundResult'); // original {name: 2}

复制代码// 第三版 实现new调用
Function.prototype.bindFn = function bind(thisArg){
    if(typeof this !== 'function'){
        throw new TypeError(this + ' must be a function');
    }
    // 存储调用bind的函数本身
    var self = this;
    // 去除thisArg的其他参数 转成数组
    var args = [].slice.call(arguments, 1);
    var bound = function(){
        // bind返回的函数 的参数转成数组
        var boundArgs = [].slice.call(arguments);
        var finalArgs = args.concat(boundArgs);
        // new 调用时，其实this instanceof bound判断也不是很准确。es6 new.target就是解决这一问题的。
        if(this instanceof bound){
            // 这里是实现上文描述的 new 的第 1, 2, 4 步
            // 1.创建一个全新的对象
            // 2.并且执行[[Prototype]]链接
            // 4.通过`new`创建的每个对象将最终被`[[Prototype]]`链接到这个函数的`prototype`对象上。
            // self可能是ES6的箭头函数，没有prototype，所以就没必要再指向做prototype操作。
            if(self.prototype){
                // ES5 提供的方案 Object.create()
                // bound.prototype = Object.create(self.prototype);
                // 但 既然是模拟ES5的bind，那浏览器也基本没有实现Object.create()
                // 所以采用 MDN ployfill方案 https://developer.mozilla.org/zh-CN/docs/Web/JavaScript/Reference/Global_Objects/Object/create
                function Empty(){}
                Empty.prototype = self.prototype;
                bound.prototype = new Empty();
            }
            // 这里是实现上文描述的 new 的第 3 步
            // 3.生成的新对象会绑定到函数调用的`this`。
            var result = self.apply(this, finalArgs);
            // 这里是实现上文描述的 new 的第 5 步
            // 5.如果函数没有返回对象类型`Object`(包含`Functoin`, `Array`, `Date`, `RegExg`, `Error`)，
            // 那么`new`表达式中的函数调用会自动返回这个新的对象。
            var isObject = typeof result === 'object' && result !== null;
            var isFunction = typeof result === 'function';
            if(isObject || isFunction){
                return result;
            }
            return this;
        }
        else{
            // apply修改this指向，把两个函数的参数合并传给self函数，并执行self函数，返回执行结果
            return self.apply(thisArg, finalArgs);
        }
    };
    return bound;
}

复制代码function Student(name){
    if(this instanceof Student){
        this.name = name;
        console.log('name', name);
    }
    else{
        throw new Error('必须通过new关键字来调用Student。');
    }
}
var student = new Student('若');
var notAStudent = Student.call(student, '川'); // 不抛出错误，且执行了。
console.log(student, 'student', notAStudent, 'notAStudent');

function Student2(name){
    if(typeof new.target !== 'undefined'){
        this.name = name;
        console.log('name', name);
    }
    else{
        throw new Error('必须通过new关键字来调用Student2。');
    }
}
var student2 = new Student2('若');
var notAStudent2 = Student2.call(student2, '川');
console.log(student2, 'student2', notAStudent2, 'notAStudent2'); // 抛出错误

复制代码Object.defineProperties(bound, {
    'length': {
        value: self.length,
    },
    'name': {
        value: 'bound ' + self.name,
    }
});

复制代码var $Array = Array;
var ArrayPrototype = $Array.prototype;
var $Object = Object;
var array_push = ArrayPrototype.push;
var array_slice = ArrayPrototype.slice;
var array_join = ArrayPrototype.join;
var array_concat = ArrayPrototype.concat;
var $Function = Function;
var FunctionPrototype = $Function.prototype;
var apply = FunctionPrototype.apply;
var max = Math.max;
// 简版 源码更复杂些。
var isCallable = function isCallable(value){
    if(typeof value !== 'function'){
        return false;
    }
    return true;
};
var Empty = function Empty() {};
// 源码是 defineProperties
// 源码是bind笔者改成bindFn便于测试
FunctionPrototype.bindFn = function bind(that) {
    var target = this;
    if (!isCallable(target)) {
        throw new TypeError('Function.prototype.bind called on incompatible ' + target);
    }
    var args = array_slice.call(arguments, 1);
    var bound;
    var binder = function () {
        if (this instanceof bound) {
            var result = apply.call(
                target,
                this,
                array_concat.call(args, array_slice.call(arguments))
            );
            if ($Object(result) === result) {
                return result;
            }
            return this;
        } else {
            return apply.call(
                target,
                that,
                array_concat.call(args, array_slice.call(arguments))
            );
        }
    };
    var boundLength = max(0, target.length - args.length);
    var boundArgs = [];
    for (var i = 0; i < boundLength; i++) {
        array_push.call(boundArgs, '$' + i);
    }
    // 这里是Function构造方式生成形参length $1, $2, $3...
    bound = $Function('binder', 'return function (' + array_join.call(boundArgs, ',') + '){ return binder.apply(this, arguments); }')(binder);

    if (target.prototype) {
        Empty.prototype = target.prototype;
        bound.prototype = new Empty();
        Empty.prototype = null;
    }
    return bound;
};

复制代码// 最终版 删除注释 详细注释版请看上文
Function.prototype.bind = Function.prototype.bind || function bind(thisArg){
    if(typeof this !== 'function'){
        throw new TypeError(this + ' must be a function');
    }
    var self = this;
    var args = [].slice.call(arguments, 1);
    var bound = function(){
        var boundArgs = [].slice.call(arguments);
        var finalArgs = args.concat(boundArgs);
        if(this instanceof bound){
            if(self.prototype){
                function Empty(){}
                Empty.prototype = self.prototype;
                bound.prototype = new Empty();
            }
            var result = self.apply(this, finalArgs);
            var isObject = typeof result === 'object' && result !== null;
            var isFunction = typeof result === 'function';
            if(isObject || isFunction){
                return result;
            }
            return this;
        }
        else{
            return self.apply(thisArg, finalArgs);
        }
    };
    return bound;
}

复制代码/login.html = anon
/login = anon
/users = perms[user:list]
/** = authc

复制代码protected boolean onAccessDenied(ServletRequest request, ServletResponse response) throws IOException {

    Subject subject = getSubject(request, response);
    // 如果未登录, 则重定向到配置的 loginUrl
    if (subject.getPrincipal() == null) {
        saveRequestAndRedirectToLogin(request, response);
    } else {
        // 如果当前用户没有权限, 则跳转到 UnauthorizedUrl
        // 如果没有配置 UnauthorizedUrl, 则返回 401 状态码.
        String unauthorizedUrl = getUnauthorizedUrl();
        if (StringUtils.hasText(unauthorizedUrl)) {
            WebUtils.issueRedirect(request, response, unauthorizedUrl);
        } else {
            WebUtils.toHttp(response).sendError(HttpServletResponse.SC_UNAUTHORIZED);
        }
    }
    return false;
}

复制代码protected boolean pathsMatch(String path, ServletRequest request) {
    String requestURI = getPathWithinApplication(request);
    log.trace("Attempting to match pattern '{}' with current requestURI '{}'...", path, requestURI);
    return pathsMatch(path, requestURI);
}

复制代码/users = perms[user:list]

复制代码public FilterChain getChain(ServletRequest request, ServletResponse response, FilterChain originalChain) {
    // 1. 判断有没有配置过滤器链, 没有一个过滤器都没有则直接返回 null
    FilterChainManager filterChainManager = getFilterChainManager();
    if (!filterChainManager.hasChains()) {
        return null;
    }

    // 2. 获取当前请求的 URL
    String requestURI = getPathWithinApplication(request);

    // 3. 遍历所有的过滤器链
    for (String pathPattern : filterChainManager.getChainNames()) {

        // 4. 判断当前请求的 URL 与过滤器链中的 URL 是否匹配.
        if (pathMatches(pathPattern, requestURI)) {
            if (log.isTraceEnabled()) {
                log.trace("Matched path pattern [" + pathPattern + "] for requestURI [" + requestURI + "].  " +
                        "Utilizing corresponding filter chain...");
            }
            // 5. 如果路径匹配, 则获取其实现类.(如 perms[user:list] 或 perms[user:delete] 都返回 perms)
            // 具体对  perms[user:list] 或 perms[user:delete] 的判断是在上面讲到的 PermissionsAuthorizationFilter 的 pathsMatch 方法中.
            return filterChainManager.proxy(originalChain, pathPattern);
        }
    }

    return null;
}

复制代码public Map<String, String> getUrlPermsMap() {
    Map<String, String> filterChainDefinitionMap = new LinkedHashMap<>();

    filterChainDefinitionMap.put("/favicon.ico", "anon");
    filterChainDefinitionMap.put("/css/**", "anon");
    filterChainDefinitionMap.put("/fonts/**", "anon");
    filterChainDefinitionMap.put("/images/**", "anon");
    filterChainDefinitionMap.put("/js/**", "anon");
    filterChainDefinitionMap.put("/lib/**", "anon");
    filterChainDefinitionMap.put("/login", "anon");

    List<Menu> menus = selectAll();
    for (Menu menu : menus) {
        String url = menu.getUrl();
        if (!"".equals(menu.getMethod())) {
            url += ("==" + menu.getMethod());
        }
        String perms = "perms[" + menu.getPerms() + "]";
        filterChainDefinitionMap.put(url, perms);
    }
    filterChainDefinitionMap.put("/**", "authc");
    return filterChainDefinitionMap;
}

复制代码package im.zhaojun.shiro;

import org.apache.shiro.web.filter.mgt.FilterChainManager;
import org.apache.shiro.web.filter.mgt.PathMatchingFilterChainResolver;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.FilterChain;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

public class RestPathMatchingFilterChainResolver extends PathMatchingFilterChainResolver {

    private static final Logger log = LoggerFactory.getLogger(RestPathMatchingFilterChainResolver.class);

    @Override
    public FilterChain getChain(ServletRequest request, ServletResponse response, FilterChain originalChain) {
        FilterChainManager filterChainManager = getFilterChainManager();
        if (!filterChainManager.hasChains()) {
            return null;
        }

        String requestURI = getPathWithinApplication(request);

        //the 'chain names' in this implementation are actually path patterns defined by the user.  We just use them
        //as the chain name for the FilterChainManager's requirements
        for (String pathPattern : filterChainManager.getChainNames()) {

            String[] pathPatternArray = pathPattern.split("==");

            // 只用过滤器链的 URL 部分与请求的 URL 进行匹配
            if (pathMatches(pathPatternArray[0], requestURI)) {
                if (log.isTraceEnabled()) {
                    log.trace("Matched path pattern [" + pathPattern + "] for requestURI [" + requestURI + "].  " +
                            "Utilizing corresponding filter chain...");
                }
                return filterChainManager.proxy(originalChain, pathPattern);
            }
        }

        return null;
    }
}

复制代码package im.zhaojun.shiro;

import org.apache.shiro.mgt.SecurityManager;
import org.apache.shiro.spring.web.ShiroFilterFactoryBean;
import org.apache.shiro.web.filter.mgt.FilterChainManager;
import org.apache.shiro.web.filter.mgt.FilterChainResolver;
import org.apache.shiro.web.filter.mgt.PathMatchingFilterChainResolver;
import org.apache.shiro.web.mgt.WebSecurityManager;
import org.apache.shiro.web.servlet.AbstractShiroFilter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.BeanInitializationException;

public class RestShiroFilterFactoryBean extends ShiroFilterFactoryBean {

    private static final Logger log = LoggerFactory.getLogger(RestShiroFilterFactoryBean.class);

    @Override
    protected AbstractShiroFilter createInstance() {

        log.debug("Creating Shiro Filter instance.");

        SecurityManager securityManager = getSecurityManager();
        if (securityManager == null) {
            String msg = "SecurityManager property must be set.";
            throw new BeanInitializationException(msg);
        }

        if (!(securityManager instanceof WebSecurityManager)) {
            String msg = "The security manager does not implement the WebSecurityManager interface.";
            throw new BeanInitializationException(msg);
        }

        FilterChainManager manager = createFilterChainManager();

        //Expose the constructed FilterChainManager by first wrapping it in a
        // FilterChainResolver implementation. The AbstractShiroFilter implementations
        // do not know about FilterChainManagers - only resolvers:
        PathMatchingFilterChainResolver chainResolver = new RestPathMatchingFilterChainResolver();
        chainResolver.setFilterChainManager(manager);

        //Now create a concrete ShiroFilter instance and apply the acquired SecurityManager and built
        //FilterChainResolver.  It doesn't matter that the instance is an anonymous inner class
        //here - we're just using it because it is a concrete AbstractShiroFilter instance that accepts
        //injection of the SecurityManager and FilterChainResolver:
        return new SpringShiroFilter((WebSecurityManager) securityManager, chainResolver);
    }

    private static final class SpringShiroFilter extends AbstractShiroFilter {
        protected SpringShiroFilter(WebSecurityManager webSecurityManager, FilterChainResolver resolver) {
            super();
            if (webSecurityManager == null) {
                throw new IllegalArgumentException("WebSecurityManager property cannot be null.");
            }
            setSecurityManager(webSecurityManager);
            if (resolver != null) {
                setFilterChainResolver(resolver);
            }
        }
    }
}

复制代码<bean id="shiroFilter" class="im.zhaojun.shiro.RestShiroFilterFactoryBean">
    <!-- 参数配置略 -->
</bean>

复制代码@Bean
public ShiroFilterFactoryBean shirFilter(SecurityManager securityManager) {
    ShiroFilterFactoryBean shiroFilterFactoryBean = new RestShiroFilterFactoryBean();
    // 参数配置略
    return shiroFilterFactoryBean;
}

复制代码package im.zhaojun.shiro.filter;

import org.apache.shiro.subject.Subject;
import org.apache.shiro.util.StringUtils;
import org.apache.shiro.web.filter.authz.PermissionsAuthorizationFilter;
import org.apache.shiro.web.util.WebUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

/**
 * 修改后的 perms 过滤器, 添加对 AJAX 请求的支持.
 */
public class RestAuthorizationFilter extends PermissionsAuthorizationFilter {

    private static final Logger log = LoggerFactory
            .getLogger(RestAuthorizationFilter.class);

    @Override
    protected boolean pathsMatch(String path, ServletRequest request) {
        String requestURI = this.getPathWithinApplication(request);

        String[] strings = path.split("==");

        if (strings.length <= 1) {
            // 普通的 URL, 正常处理
            return this.pathsMatch(strings[0], requestURI);
        } else {
            // 获取当前请求的 http method.
            String httpMethod = WebUtils.toHttp(request).getMethod().toUpperCase();

            // 匹配当前请求的 http method 与 过滤器链中的的是否一致
            return httpMethod.equals(strings[1].toUpperCase()) && this.pathsMatch(strings[0], requestURI);
        }
    }
}

复制代码/**
 * 当没有权限被拦截时:
 *          如果是 AJAX 请求, 则返回 JSON 数据.
 *          如果是普通请求, 则跳转到配置 UnauthorizedUrl 页面.
 */
@Override
protected boolean onAccessDenied(ServletRequest request, ServletResponse response) throws IOException {
    Subject subject = getSubject(request, response);
    // 如果未登录
    if (subject.getPrincipal() == null) {
        // AJAX 请求返回 JSON
        if (im.zhaojun.util.WebUtils.isAjaxRequest(WebUtils.toHttp(request))) {
            if (log.isDebugEnabled()) {
                log.debug("用户: [{}] 请求 restful url : {}, 未登录被拦截.", subject.getPrincipal(), this.getPathWithinApplication(request));                }
            Map<String, Object> map = new HashMap<>();
            map.put("code", -1);
            im.zhaojun.util.WebUtils.writeJson(map, response);
        } else {
            // 其他请求跳转到登陆页面
            saveRequestAndRedirectToLogin(request, response);
        }
    } else {
        // 如果已登陆, 但没有权限
        // 对于 AJAX 请求返回 JSON
        if (im.zhaojun.util.WebUtils.isAjaxRequest(WebUtils.toHttp(request))) {
            if (log.isDebugEnabled()) {
                log.debug("用户: [{}] 请求 restful url : {}, 无权限被拦截.", subject.getPrincipal(), this.getPathWithinApplication(request));
            }

            Map<String, Object> map = new HashMap<>();
            map.put("code", -2);
            map.put("msg", "没有权限啊!");
            im.zhaojun.util.WebUtils.writeJson(map, response);
        } else {
            // 对于普通请求, 跳转到配置的 UnauthorizedUrl 页面.
            // 如果未设置 UnauthorizedUrl, 则返回 401 状态码
            String unauthorizedUrl = getUnauthorizedUrl();
            if (StringUtils.hasText(unauthorizedUrl)) {
                WebUtils.issueRedirect(request, response, unauthorizedUrl);
            } else {
                WebUtils.toHttp(response).sendError(HttpServletResponse.SC_UNAUTHORIZED);
            }
        }

    }
    return false;
}

复制代码<bean id="shiroFilter" class="im.zhaojun.shiro.RestShiroFilterFactoryBean">
    <!-- 参数配置略 -->
    <property name="filters">
        <map>
            <entry key="perms" value-ref="restAuthorizationFilter"/>
        </map>
    </property>
</bean>

<bean id="restAuthorizationFilter" class="im.zhaojun.shiro.filter.RestAuthorizationFilter"/>

复制代码@Bean
public ShiroFilterFactoryBean shirFilter(SecurityManager securityManager) {
    ShiroFilterFactoryBean shiroFilterFactoryBean = new RestShiroFilterFactoryBean();
    Map<String, Filter> filters = shiroFilterFactoryBean.getFilters();
    filters.put("perms", new RestAuthorizationFilter());

    // 其他配置略
    return shiroFilterFactoryBean;
}

复制代码static final int hash(Object key) {
    int h;
    return (key == null) ? 0 : (h = key.hashCode()) ^ (h >>> 16);
}

复制代码public V put(K key, V value) {
    return putVal(hash(key), key, value, false, true);
}

复制代码final V putVal(int hash, K key, V value, boolean onlyIfAbsent,
               boolean evict) {
    HashMap.Node<K, V>[] tab;
    HashMap.Node<K, V> p;
    int n, i;
    if ((tab = table) == null || (n = tab.length) == 0)
        //初始化哈希表
        n = (tab = resize()).length;
    if ((p = tab[i = (n - 1) & hash]) == null)
        //通过哈希值找到对应的位置，如果该位置还没有元素存在，直接插入
        tab[i] = newNode(hash, key, value, null);
    else {
        HashMap.Node<K, V> e;
        K k;
        //如果该位置的元素的 key 与之相等，则直接到后面重新赋值
        if (p.hash == hash && ((k = p.key) == key || (key != null && key.equals(k))))
            e = p;
        else if (p instanceof HashMap.TreeNode)
            //如果当前节点为树节点，则将元素插入红黑树中
            e = ((HashMap.TreeNode<K, V>) p).putTreeVal(this, tab, hash, key, value);
        else {
            //否则一步步遍历链表
            for (int binCount = 0; ; ++binCount) {
                if ((e = p.next) == null) {
                    //插入元素到链尾
                    p.next = newNode(hash, key, value, null);
                    if (binCount >= TREEIFY_THRESHOLD - 1)
                        //元素个数大于等于 8，改造为红黑树
                        treeifyBin(tab, hash);
                    break;
                }
                //如果该位置的元素的 key 与之相等，则重新赋值
                if (e.hash == hash && ((k = e.key) == key || (key != null && key.equals(k))))
                    break;
                p = e;
            }
        }
        //前面当哈希表中存在当前key时对e进行了赋值，这里统一对该key重新赋值更新
        if (e != null) { 
            V oldValue = e.value;
            if (!onlyIfAbsent || oldValue == null)
                e.value = value;
            afterNodeAccess(e);
            return oldValue;
        }
    }
    ++modCount;
    //检查是否超出 threshold 限制，是则进行扩容
    if (++size > threshold)
        resize();
    afterNodeInsertion(evict);
    return null;
}

复制代码if ((tab = table) == null || (n = tab.length) == 0)
      n = (tab = resize()).length;

复制代码final void treeifyBin(HashMap.Node<K,V>[] tab, int hash) {
    int n, index; HashMap.Node<K,V> e;
    if (tab == null || (n = tab.length) < MIN_TREEIFY_CAPACITY)
        resize();
    else if ((e = tab[index = (n - 1) & hash]) != null) {
        //......
}

复制代码if ((e.hash & oldCap) == 0) {
    ...
} else {
    ...
}

复制代码final HashMap.Node<K,V> getNode(int hash, Object key) {
    HashMap.Node<K,V>[] tab; HashMap.Node<K,V> first, e; int n; K k;
    if ((tab = table) != null && (n = tab.length) > 0 && (first = tab[(n - 1) & hash]) != null) {
        //检查当前位置的第一个元素，如果正好是该元素，则直接返回
        if (first.hash == hash && ((k = first.key) == key || (key != null && key.equals(k))))
            return first;
        if ((e = first.next) != null) {
            //否则检查是否为树节点，则调用 getTreeNode 方法获取树节点
            if (first instanceof HashMap.TreeNode)
                return ((HashMap.TreeNode<K,V>)first).getTreeNode(hash, key);
            //遍历整个链表，寻找目标元素
            do {
                if (e.hash == hash &&
                        ((k = e.key) == key || (key != null && key.equals(k))))
                    return e;
            } while ((e = e.next) != null);
        }
    }
    return null;
}

复制代码//组件内注册路由
public interface SampleService {
    @Path("/main")
    @Activity(MainActivity.class)
    void startMainActivity(@Query("key") String key);
}

//其余组件唤起页面
new DeepLinkClient(context).buildRequest("old://app/main?key=value").addQuery("key2", "2").start();

复制代码 //组件内 api module 接口声明
@Service
public interface TestService {
    void sayHello();
}

//组件内 imp module 接口实现
@ServiceImpl
public class TestServiceImpl implements TestService {
    @Override
    public void sayHello() {
    }
}

//跨组件调用
compile 'com.u51.android:test-lib-api:$version'

CommentService service = ServicesLoader.getInstance().getService(TestService.class);
service.sayHello();

复制代码@JsPlugin(name = TestPlugin.PLUGIN_NAME, loadOnInit = false, version = 1)
public class TestPlugin extends EnNiuJsPlugin {
    public static final String PLUGIN_NAME = "TestPlugin";
    
    @Override
    public String getPluginName() {
        return PLUGIN_NAME;
    }
	...
    @Override
    public boolean onExecute(String args) {
        doSomething(); 					  
        callbackContext.callback(...);
        return true;
    }
}

复制代码public class ENBridgeModule extends WXModule {
    @JSMethod
    public synchronized void send(String method, String args, JSCallback jsCallback) {
        ...
        weexWebView = weexEngine.getWeexVirtualWebView();
        EnNiuJsBridge enNiuJsBridge = weexWebView.getEnNiuJsBridge();
        enNiuJsBridge.notify(pg);
    }
}

复制代码try {
    c.getClassPool().get(callClassName)
    isClassNotFound = false
    m.getMethod()
} catch (NotFoundException e) {
    if (isClassNotFound) {
        dealException(String.format("在%s类中的第%d行是用到的%s类不存在", className, line, callClassName))
    } else {
        dealException(String.format("在%s类中的第%d行是用到的%s类的%s方法不存在", className, line, callClassName, methodName))
    }
}

复制代码modifyPom { pom ->
    pom.dependencies.findAll { dep -> dep.groupId == rootProject.name }.collect { dep ->
        dep.groupId = pom.groupId = rootProject.groupId
        dep.version = pom.version = rootProject.sdkVersion
    }
}

复制代码    for img in imgs:
        # print(etree.tostring(img))
        img_url = img.get('data-original')  # 不知道为什么多个 ！data ,去掉它
        img_url = img_url.replace("!dta", "")

复制代码        alt = img.get('alt') # 获取图片名字
        # alt 可能某些情况下需要处理非法字符（这些字符不可以当做名字保存）
        suffix = os.path.splitext(img_url)[1] # 对url进行分割，取数组中的第二位，得到后缀名
        filename = alt + suffix
        request.urlretrieve(img_url, 'images/' + filename) # 保存图片

复制代码def parse_page(url):

    headers = {
        'User-Agent':'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 Safari/537.36'
    }
    response = requests.get(url, headers=headers)
    # print(response.text) # 打印html源代码
    html = etree.HTML(response.text)
    imgs = html.xpath("//div[@class='page-content text-center']//img[@class!='gif']")
    for img in imgs:
        # print(etree.tostring(img))
        img_url = img.get('data-original')  # 不知道为什么多个 ！data ,去掉它
        img_url = img_url.replace("!dta", "")
        # print(img_url)
        alt = img.get('alt') # 获取图片名字
        # alt 可能某些情况下需要处理非法字符（这些字符不可以当做名字保存）
        print(alt)
        suffix = os.path.splitext(img_url)[1] # 对url进行分割，取数组中的第二位，得到后缀名
        filename = alt + suffix
        print(filename)
        request.urlretrieve(img_url, 'images/' + filename) # 保存图片

def main():
    for x in range(1,51): # # 爬取前50页 range(1,3) 这里相当于 1 2
        url = 'https://www.doutula.com/photo/list/?page=%d' % x
        parse_page(url)
        break

复制代码`[INFO] 20180913 19:24:01.442 method start aaa`
[INFO] 20180913 19:24:01.452 method start bbb
[INFO] 20180913 19:24:01.456 do something ccc
[INFO] 20180913 19:24:01.562 method end aaa
...

复制代码`#!/bin/bash`

# 获取准确时间的函数
function get_acc_time() {
    arr=($1)
    date_str=${arr[1]}" "${arr[2]}
    # date -d "date_str" "+%format" 可以指定输入日期，以替代默认的当前时间
    # cut 根据 '.' 切分，并取第二个字段
    echo `date -d "$date_str" "+%s"`"."`echo  ${arr[2]} | cut -d '.' -f2`
}

# 使用 -A 声明关联数组
declare -A arr_start
declare -A arr_end

# 构造开始时间数组
while read -r start_line
do
    arr_start[${arr[5]}]=`get_acc_time $start_line`
done < $start_file

# 构造结束时间数组
while read -r end_line
do
    arr_end[${arr[5]}]=`get_acc_time $end_line`
done < $end_file

# 遍历结束时间数组
for request in ${!arr_end[*]}
do
    end_time=${arr_end[$request]}
    start_time=${arr_start[$request]}
    if [ -z "$start_time" ]; then
        continue;
    fi
    # 直接使用 bc 不会显示小数点前的 0
    echo `print "%.3f" echo "scale=3;$end_time-$start_time"| bc` >> $out_file
done

复制代码`开始日志 aaa bbb ccc ddd eee fff`
结束日志 aaa bbb ccc ddd eee fff

复制代码`#!/bin/bash`

function get_acc_time() {
    date_str=$1" "$2
    acc_time=`date -d "$date_str" "+%s"`"."`echo  $2 | cut -d '.' -f2`
    echo $acc_time
}

total=`cat $end_file | wc -l`
i=0
while read -r start_line
do
    i=`expr $i + 1`
    arr_start=($start_line)

    # 如果取不到的话去下一行取
    for j in `seq $i $total`
    do
        end_line=`awk "NR==$j" $end_file` // 用 awk 直接取到第 N 行的数据
        arr_end=($end_line)

        # 判断两条日志的 unique_id 一样
        if [ "${arr_start[5]}" = "${arr_end[5]}" ];then
            break
        fi
            i=`expr $i + 1`
    done

    start_time=`get_acc_time ${arr_start[1]} ${arr_start[2]}`
    end_time=`get_acc_time ${arr_end[1]} ${arr_end[2]}`

    echo `print "%.3f" echo "scale=3;$end_time-$start_time"| bc` >> $out_file
done < $start_file

复制代码`#!/bin/bash`
function get_time() {
        date_str=$1" "`echo $2 | cut -d '.' -f1`
        acc_time=`date -d "$date_str" "+%s"`"."`echo  $2 | cut -d '.' -f2`
    echo $acc_time
}

SAVEIFS=$IFS # 保存系统原来的分隔符（空格）
IFS=$'\n' # 将分隔符设置为换行，这样才能将文件按行分隔为数组

start_lines=(`cat $start_file`)
end_lines=(`cat $end_file`)

total=`cat $end_file | wc -l`
i=0
IFS=$SAVEIFS # 将分隔符还设置回空格，后续使用它将每行日志切分为数组
for start_line in ${start_lines[*]}
do
    arr_start=($start_line)

    for j in `seq $i $total`
    do
        end_line=${end_lines[$j]}
        arr_end=($end_line)

        if [  -z "$end_line"  -o "${arr_start[5]}" = "${arr_end[5]}" ];then
            break
        fi
            i=`expr $i + 1`
    done

    i=`expr $i + 1`
    start_time=`get_time ${arr_start[1]} ${arr_start[2]}`
    end_time=`get_time ${arr_end[1]} ${arr_end[2]}`

    echo `print "%.3f" echo "scale=3;$end_time-$start_time"| bc` >> $out_file
done

复制代码`#!/bin/bash`
function get_time() {
    date_str=$1" "`echo $2 | cut -d '.' -f1`
    acc_time=`date -d "$date_str" "+%s"`"."`echo  $2 | cut -d '.' -f2`
    echo $acc_time
}

while read -r start_line
do
    arr_s=($start_line)

    start_time=`get_time ${arr_s[1]} ${arr_s[2]}`
    end_time=`get_time ${arr_s[5]} ${arr_s[6]}`

    # 每行前面输出一个 unique_id
    echo -e ${arr_s[5]}" \c" >> $out_file
    echo `print "%.3f" echo "scale=3;$end_time-$start_time"| bc` >> $out_file
done < $start_file

![](https://gitee.com/songjianzaina/juejin_p7/raw/master/img/c6ec770b6c4e6de9be806d27694d636e7b1e98c86991d4682dae0085c5049c42)


可以看出进程创建一个子进程并执行命令，到最后回收子进程的消耗是很大的，需要对子进程进行信号处理，文件描述符等操作。最终工作的代码只有一个 `write` 且耗时很短。


由于脚本是完全同步运行的，所以子进程耗时很长，主进程的 read 也只能等待，导致整个脚本的耗时增加。


为了验证我的猜测，我把脚本简写后，使用 `time` 命令统计了耗时分布。