JWT 进阶 -- JJWT

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###jwt是什么?

JWTs是JSON对象的编码表示。JSON对象由零或多个名称/值对组成，其中名称为字符串，值为任意JSON值。JWT有助于在clear(例如在URL中)发送这样的信息，可以被信任为不可读(即加密的)、不可修改的(即签名)和URL - safe(即Base64编码的)。

###jwt的组成

Header: 标题包含了令牌的元数据，并且在最小包含签名和/或加密算法的类型
Claims: Claims包含您想要签署的任何信息
JSON Web Signature (JWS): 在header中指定的使用该算法的数字签名和声明

例如：

Header:{"alg": "HS256","typ": "JWT"
}Claims:{"sub": "1234567890","name": "John Doe","admin": true
}Signature:base64UrlEncode(Header) + "." + base64UrlEncode(Claims),

加密生成的token：

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###如何保证 JWT 安全

有很多库可以帮助您创建和验证JWT，但是当使用JWT时，仍然可以做一些事情来限制您的安全风险。在您信任JWT中的任何信息之前，请始终验证签名。这应该是给定的。换句话说，如果您正在传递一个秘密签名密钥到验证签名的方法，并且签名算法被设置为“none”，那么它应该失败验证。
确保签名的秘密签名，用于计算和验证签名。秘密签名密钥只能由发行者和消费者访问，不能在这两方之外访问。
不要在JWT中包含任何敏感数据。这些令牌通常是用来防止操作(未加密)的，因此索赔中的数据可以很容易地解码和读取。
如果您担心重播攻击，包括一个nonce(jti索赔)、过期时间(exp索赔)和创建时间(iat索赔)。这些在JWT规范中定义得很好。

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###jwt的框架：JJWT

JJWT是一个提供端到端的JWT创建和验证的Java库。永远免费和开源(Apache License，版本2.0)，JJWT很容易使用和理解。它被设计成一个以建筑为中心的流畅界面，隐藏了它的大部分复杂性。

JJWT的目标是最容易使用和理解用于在JVM上创建和验证JSON Web令牌(JWTs)的库。
JJWT是基于JWT、JWS、JWE、JWK和JWA RFC规范的Java实现。
JJWT还添加了一些不属于规范的便利扩展，比如JWT压缩和索赔强制。

####规范兼容:

创建和解析明文压缩JWTs
创建、解析和验证所有标准JWS算法的数字签名紧凑JWTs(又称JWSs):
HS256: HMAC using SHA-256
HS384: HMAC using SHA-384
HS512: HMAC using SHA-512
RS256: RSASSA-PKCS-v1_5 using SHA-256
RS384: RSASSA-PKCS-v1_5 using SHA-384
RS512: RSASSA-PKCS-v1_5 using SHA-512
PS256: RSASSA-PSS using SHA-256 and MGF1 with SHA-256
PS384: RSASSA-PSS using SHA-384 and MGF1 with SHA-384
PS512: RSASSA-PSS using SHA-512 and MGF1 with SHA-512
ES256: ECDSA using P-256 and SHA-256
ES384: ECDSA using P-384 and SHA-384
ES512: ECDSA using P-521 and SHA-512

###这里以github上的demo演示，理解原理，集成到自己项目中即可。

####应用采用 spring boot + angular + jwt

结构图

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Maven 引进 : pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>com.nibado.example</groupId><artifactId>jwt-angular-spring</artifactId><version>0.0.2-SNAPSHOT</version><properties><maven.compiler.source>1.8</maven.compiler.source><maven.compiler.target>1.8</maven.compiler.target><commons.io.version>2.4</commons.io.version><jjwt.version>0.6.0</jjwt.version><junit.version>4.12</junit.version><spring.boot.version>1.5.3.RELEASE</spring.boot.version></properties><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId><version>${spring.boot.version}</version><executions><execution><goals><goal>repackage</goal></goals></execution></executions></plugin></plugins></build><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId><version>${spring.boot.version}</version></dependency><dependency><groupId>commons-io</groupId><artifactId>commons-io</artifactId><version>${commons.io.version}</version></dependency><dependency><groupId>io.jsonwebtoken</groupId><artifactId>jjwt</artifactId><version>${jjwt.version}</version></dependency><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>${junit.version}</version></dependency></dependencies>
</project>

WebApplication.java

package com.nibado.example.jwtangspr;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;@EnableAutoConfiguration
@ComponentScan
@Configuration
public class WebApplication {//过滤器@Beanpublic FilterRegistrationBean jwtFilter() {final FilterRegistrationBean registrationBean = new FilterRegistrationBean();registrationBean.setFilter(new JwtFilter());registrationBean.addUrlPatterns("/api/*");return registrationBean;}public static void main(final String[] args) throws Exception {SpringApplication.run(WebApplication.class, args);}}

JwtFilter.java

package com.nibado.example.jwtangspr;import java.io.IOException;import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;import org.springframework.web.filter.GenericFilterBean;import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureException;public class JwtFilter extends GenericFilterBean {@Overridepublic void doFilter(final ServletRequest req,final ServletResponse res,final FilterChain chain) throws IOException, ServletException {final HttpServletRequest request = (HttpServletRequest) req;//客户端将token封装在请求头中，格式为（Bearer后加空格）：Authorization：Bearer +tokenfinal String authHeader = request.getHeader("Authorization");if (authHeader == null || !authHeader.startsWith("Bearer ")) {throw new ServletException("Missing or invalid Authorization header.");}//去除Bearer 后部分final String token = authHeader.substring(7);try {//解密token，拿到里面的对象claimsfinal Claims claims = Jwts.parser().setSigningKey("secretkey").parseClaimsJws(token).getBody();//将对象传递给下一个请求request.setAttribute("claims", claims);}catch (final SignatureException e) {throw new ServletException("Invalid token.");}chain.doFilter(req, res);}}

UserController.java

package com.nibado.example.jwtangspr;import java.util.Arrays;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;import javax.servlet.ServletException;import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;@RestController
@RequestMapping("/user")
public class UserController {//这里模拟数据库private final Map<String, List<String>> userDb = new HashMap<>();@SuppressWarnings("unused")private static class UserLogin {public String name;public String password;}public UserController() {userDb.put("tom", Arrays.asList("user"));userDb.put("wen", Arrays.asList("user", "admin"));}/*以上是模拟数据库，并往数据库插入tom和sally两条记录*/@RequestMapping(value = "login", method = RequestMethod.POST)public LoginResponse login(@RequestBody final UserLogin login)throws ServletException {if (login.name == null || !userDb.containsKey(login.name)) {throw new ServletException("Invalid login");}//加密生成tokenreturn new LoginResponse(Jwts.builder().setSubject(login.name).claim("roles", userDb.get(login.name)).setIssuedAt(new Date()).signWith(SignatureAlgorithm.HS256, "secretkey").compact());}@SuppressWarnings("unused")private static class LoginResponse {public String token;public LoginResponse(final String token) {this.token = token;}}
}

ApiController.java

package com.nibado.example.jwtangspr;import io.jsonwebtoken.Claims;import java.util.List;import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;@RestController
@RequestMapping("/api")
public class ApiController {@SuppressWarnings("unchecked")@RequestMapping(value = "role/{role}", method = RequestMethod.GET)public Boolean login(@PathVariable final String role,final HttpServletRequest request) throws ServletException {final Claims claims = (Claims) request.getAttribute("claims");return ((List<String>) claims.get("roles")).contains(role);}
}

index.html

<!doctype html>
<html ng-app="myApp">
<head><meta charset="utf-8"/><meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"/><title>JSON Web Token / AngularJS / Spring Boot example</title><meta name="description" content=""><meta name="viewport" content="width=device-width"><link rel="stylesheet" href="libs/bootstrap/css/bootstrap.css"><script src="libs/jquery/jquery.js"></script><script src="libs/bootstrap/js/bootstrap.js"></script><script src="libs/angular/angular.js"></script><script src="app.js"></script>
</head>
<body>
<div class="container" ng-controller='MainCtrl'><h1>{{greeting}}</h1><div ng-show="!loggedIn()">Please log in (tom and sally are valid names)</br><form ng-submit="login()">Username: <input type="text" ng-model="userName"/><span><input type="submit" value="Login"/></form></div><div class="alert alert-danger" role="alert" ng-show="error.data.message"><span class="glyphicon glyphicon-exclamation-sign" aria-hidden="true"></span><span class="sr-only">Error:</span>{{error.data.message}}</div>	<div ng-show="loggedIn()"><div class="row"><div class="col-md-6"><h3><span class="label label-success">Success!</span> Welcome {{userName}}</h3><a href ng-click="logout()">(logout)</a></div><div class="col-md-4"><div class="row header"><div class="col-sm-4">{{userName}} is a</div></div><div class="row"><div class="col-sm-2">User</div><div class="col-sm-2"><span class="glyphicon glyphicon-ok" aria-hidden="true" ng-show="roleUser"></span></div></div><div class="row"><div class="col-sm-2">Admin</div><div class="col-sm-2"><span class="glyphicon glyphicon-ok" aria-hidden="true" ng-show="roleAdmin"></span></div></div>	<div class="row"><div class="col-sm-2">Foo</div><div class="col-sm-2"><span class="glyphicon glyphicon-ok" aria-hidden="true" ng-show="roleFoo"></span></div></div>				</div></div></div>
</div>
</body>
</html>

app.js

var appModule = angular.module('myApp', []);appModule.controller('MainCtrl', ['mainService','$scope','$http',function(mainService, $scope, $http) {$scope.greeting = 'Welcome to the JSON Web Token / AngularJR / Spring example!';$scope.token = null;$scope.error = null;$scope.roleUser = false;$scope.roleAdmin = false;$scope.roleFoo = false;$scope.login = function() {$scope.error = null;mainService.login($scope.userName).then(function(token) {$scope.token = token;$http.defaults.headers.common.Authorization = 'Bearer ' + token;$scope.checkRoles();},function(error){$scope.error = error$scope.userName = '';});}$scope.checkRoles = function() {mainService.hasRole('user').then(function(user) {$scope.roleUser = user});mainService.hasRole('admin').then(function(admin) {$scope.roleAdmin = admin});mainService.hasRole('foo').then(function(foo) {$scope.roleFoo = foo});}$scope.logout = function() {$scope.userName = '';$scope.token = null;$http.defaults.headers.common.Authorization = '';}$scope.loggedIn = function() {return $scope.token !== null;}} ]);appModule.service('mainService', function($http) {return {login : function(username) {return $http.post('/user/login', {name: username}).then(function(response) {return response.data.token;});},hasRole : function(role) {return $http.get('/api/role/' + role).then(function(response){console.log(response);return response.data;});}};
});