json web token的简单实现 JAVA

来源：互联网发布：js 日期控件编辑：程序博客网时间：2024/05/18 23:29

1.简介

json web token(JWT)是一种新的用户认证方式,不同与以前的Session.

JWT不需要服务器端存储用户信息,当用户登录后,服务器将用户信息放入加密放入token,需要时再通过对token解密获取.

关于更多JWT的介绍请自行搜索,这里提供一篇便于理解的文章: http://www.tuicool.com/articles/uuAzAbU 八幅漫画理解使用JSON Web Token设计单点登录系统

2.代码

下面提供一种JWT的简单实现.这个例子实现的功能是:

1) 用户访问login.jsp进行登录操作.

2) 用户访问myServlet时,若用户已登录则跳转至info.jsp显示用户名,未登录则跳转至login.jsp.

ps:这个demo是基于最基本的serlvet,jsp实现的,仅供参考,实际开发中并不会这么玩~

login.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Insert title here</title></head><body><form action="Servlet/myServlet" method="post">帐号:<input type="text" name="account">密码:<input type="password" name="password"><input type="submit" value="登录"> </form></body></html>

MyServlet.java

package com.hxuhao.servlet;import java.io.IOException;import java.io.PrintWriter;import java.util.HashMap;import java.util.Map.Entry;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.Cookie;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.hxuhao.model.User;import com.hxuhao.utils.JWTUtil;import io.jsonwebtoken.Claims;/** * Servlet implementation class MyServlet */@WebServlet("/MyServlet")public class MyServlet extends HttpServlet {private static final long serialVersionUID = 1L;       // 模拟的数据库private HashMap<Integer,User> users = new HashMap<>();@Overridepublic void init() throws ServletException {// TODO Auto-generated method stubsuper.init();users.put(Integer.valueOf(1), new User(1,"test1","123","测试用户1"));users.put(Integer.valueOf(2), new User(2,"test2","123","测试用户2"));}/** * @see HttpServlet#service(HttpServletRequest request, HttpServletResponse response) */protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stubrequest.setCharacterEncoding("utf-8");response.setCharacterEncoding("utf-8");if(request.getMethod().equals("POST")){doPost(request, response);}else{doGet(request, response);}}/** * 查看信息 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stub//response.getWriter().append("Served at: ").append(request.getContextPath());// 验证用户Cookie[] cookies =  request.getCookies();//User user=null;String username = null;if(cookies!=null){for(int i=0;i<cookies.length;i++){System.out.println(cookies[i].getName() + " : " + cookies[i].getValue());if(cookies[i].getName().equals("JWT")){Cookie cookie = cookies[i];try {// 检查tokenClaims  claims = JWTUtil.parseJWT(cookie.getValue());username = claims.getSubject();System.out.println("name : " + username);} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}}}}if(username!=null){request.setAttribute("username", username);request.getRequestDispatcher("../info.jsp").forward(request, response);}else{//System.out.println("SendRedirect");response.sendRedirect("../login.jsp");}}/** * 登录 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stubString account = request.getParameter("account");String password = request.getParameter("password");System.out.println(account + " : " + password);String token = ""; for(Entry<Integer, User> item : users.entrySet()){User u = item.getValue();if(u.getAccount().equals(account)&&u.getPassword().equals(password)){try {System.out.println(u.getName());token = JWTUtil.createJWT(String.valueOf(u.getId()), u.getName(), 1000*60*10);// 将token放进CookieCookie cookie = new Cookie("JWT", token);cookie.setPath("/");// 过期时间设为10mincookie.setMaxAge(60*10);response.addCookie(cookie);} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}}}PrintWriter pw = response.getWriter();if(!token.equals("")){System.out.println(token);pw.print("login succeed : " + token);}else{pw.print("login failed : error account or password");}pw.flush();pw.close();}}

info.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Insert title here</title></head><body><h2>Hello,<%=request.getAttribute("username") %></h2></body></html>

JWTUtil.java

package com.hxuhao.utils;import java.util.Date;import javax.crypto.SecretKey;import javax.crypto.spec.SecretKeySpec;import org.apache.commons.codec.binary.Base64;import io.jsonwebtoken.Claims;import io.jsonwebtoken.JwtBuilder;import io.jsonwebtoken.Jwts;import io.jsonwebtoken.SignatureAlgorithm;public class JWTUtil {    private static final String profiles="hxhxhxhxh";/** * 由字符串生成加密key * @return */    private static SecretKey generalKey(){String stringKey = profiles;byte[] encodedKey = Base64.decodeBase64(stringKey);    SecretKey key = new SecretKeySpec(encodedKey, 0, encodedKey.length, "AES");    return key;}/** * 创建jwt * @param id * @param subject * @param ttlMillis * @return * @throws Exception */public static String createJWT(String id, String subject, long ttlMillis) throws Exception {SignatureAlgorithm signatureAlgorithm = SignatureAlgorithm.HS256;long nowMillis = System.currentTimeMillis();Date now = new Date(nowMillis);SecretKey key = generalKey();JwtBuilder builder = Jwts.builder().setId(id).setIssuedAt(now).setSubject(subject)    .signWith(signatureAlgorithm, key);if (ttlMillis >= 0) {    long expMillis = nowMillis + ttlMillis;    Date exp = new Date(expMillis);    builder.setExpiration(exp);}return builder.compact();}/** * 解析jwt * @param jwt * @return * @throws Exception */public static Claims parseJWT(String jwt) throws Exception{SecretKey key = generalKey();Claims claims = Jwts.parser()            .setSigningKey(key)   .parseClaimsJws(jwt).getBody();return claims;}}

3.凑数

1.整个demo以上传github : Hxuhao233 .需要的可以去看看(应该没人去吧2333333)

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