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一、后端代码

1.响应工具类

package com.etime.util;import com.etime.vo.ResponseModel;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.http.MediaType;import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;/*** @Date 2024/6/10 10:00* @Author liukang**/
public class ResponseUtil {public static void write(ResponseModel rm, HttpServletResponse response) throws IOException {// 构造响应头response.setContentType(MediaType.APPLICATION_JSON_VALUE);response.setCharacterEncoding("utf-8");// 解决跨域问题 设置跨域头response.setHeader("Access-Control-Allow-Origin","*");// 输出流PrintWriter out = response.getWriter();// 输出out.write(new ObjectMapper().writeValueAsString(rm));// 关闭流out.close();}
}

2.jwt工具类

package com.etime.util;import io.jsonwebtoken.*;import java.util.Date;
import java.util.Map;
import java.util.UUID;/*** @Date 2024/6/10 10:04* @Author liukang**/
public class JwtUtil {private static String secret = "secret";/*** 创建jwt* @author liukang* @date 10:36 2024/6/10* @param expire* @param map* @return java.lang.String**/public static String generateToken(long expire, Map map){// 床jwt构造器JwtBuilder jwtBuilder = Jwts.builder();// 生成jwt字符串String jwt = jwtBuilder//头部.setHeaderParam("typ","JWT").setHeaderParam("alg","HS256")// 载荷.setClaims(map) // 设置多个自定义数据  位置只能放在前面，如果放在后面，那前面的载荷会失效.setId(UUID.randomUUID().toString())// 唯一标识.setIssuer("liukang")// 签发人.setIssuedAt(new Date())// 签发时间.setSubject("jwtDemo")// 主题.setExpiration(new Date(System.currentTimeMillis()+expire))//过期时间// 签名.signWith(SignatureAlgorithm.HS256,secret).compact();return jwt;}/*** 创建jwt* @author liukang* @date 10:36 2024/6/10* @param expire* @return java.lang.String**/public static String generateToken(long expire){// 床jwt构造器JwtBuilder jwtBuilder = Jwts.builder();// 生成jwt字符串String jwt = jwtBuilder//头部.setHeaderParam("typ","JWT").setHeaderParam("alg","HS256")// 载荷.setId(UUID.randomUUID().toString())// 唯一标识.setIssuer("liukang")// 签发人.setIssuedAt(new Date())// 签发时间.setSubject("jwtDemo")// 主题.setExpiration(new Date(System.currentTimeMillis()+expire))//过期时间// 签名.signWith(SignatureAlgorithm.HS256,secret).compact();return jwt;}/*** 解析jwt* @author liukang* @date 10:36 2024/6/10* @param jwt* @return io.jsonwebtoken.Claims**/public static Claims parseToken(String jwt){Jws<Claims> claimsJws = Jwts.parser().setSigningKey(secret).parseClaimsJws(jwt);Claims playload = claimsJws.getBody();return playload;}
}

3.登录用户实体类

package com.etime.entity;import lombok.Data;/*** @Date 2024/6/10 10:39* @Author liukang**/
@Data
public class User {private String username;private String password;
}

4.登录接口

package com.etime.controller;import com.etime.entity.User;
import com.etime.util.JwtUtil;
import com.etime.vo.ResponseModel;
import org.springframework.web.bind.annotation.*;/*** @Date 2024/6/10 10:38* @Author liukang**/
@RestController
@CrossOrigin
public class LoginController {@PostMapping("/login")public ResponseModel login(@RequestBody User user){Integer code = 200;String msg = "success";String token = null;if(user.getUsername().equals("admin")&&user.getPassword().equals("123")){// 生成jwttoken = JwtUtil.generateToken(1000*10);// 设置有效期为10s}else {code = 500;msg = "failure";}return new ResponseModel(code,msg,token);}}

5.测试接口

package com.etime.controller;import com.etime.vo.ResponseModel;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RestController;/*** @Date 2024/6/10 12:51* @Author liukang**/
@CrossOrigin
@RestController
public class TestController {@PostMapping("/test")public ResponseModel test() {return new ResponseModel(200,"success","测试请求接口成功!");}}

6.过滤器

package com.etime.filter;import com.etime.util.JwtUtil;
import com.etime.util.ResponseUtil;
import com.etime.vo.ResponseModel;
import com.sun.deploy.net.HttpResponse;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpRequest;
import org.springframework.util.StringUtils;import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;/*** @Description jwt过滤器* @Date 2024/6/10 9:46* @Author liukang**/
@WebFilter(urlPatterns = "/*") // 过滤所有路径
public class JwtFilter implements Filter {@Overridepublic void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {// 得到两个对象HttpServletRequest request =  (HttpServletRequest) servletRequest;HttpServletResponse response =  (HttpServletResponse) servletResponse;//直接放行if(HttpMethod.OPTIONS.toString().equals(request.getMethod())){filterChain.doFilter(request,response);return;}String requestURI = request.getRequestURI(); // 不含主机和端口号if(requestURI.contains("/login")){filterChain.doFilter(request,response);return;}// 得到请求头的信息（accessToken）String token = request.getHeader("accessToken");if(!StringUtils.hasText(token)){//响应前端错误的消息提示ResponseModel responseModel = new ResponseModel(500,"failure","令牌缺失！");ResponseUtil.write(responseModel,response);return;}// 解析Token信息try {JwtUtil.parseToken(token);}catch (Exception e){//响应前端错误的消息提示ResponseModel responseModel = new ResponseModel(401,"failure","令牌过期！");ResponseUtil.write(responseModel,response);return;}filterChain.doFilter(request,response);}
}

7.启动类

package com.etime;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;/*** @Author liukang* @Date 2022/7/4 11:32*/
@SpringBootApplication
@ServletComponentScan(basePackages = "com.etime.filter")// 这个包下激活WebFilter这个注解
public class Application {public static void main(String[] args) {SpringApplication.run(Application.class);}
}

二、前端代码

1.登录页

<template><div class="hello"><form>用户名：<input v-model="username"/><br>密码<input v-model="password" /><br><button @click="login">登录</button></form></div></template><script>export default {data () {return {username:'',password:'',}},methods:{login(){this.axios.post('http://localhost:8088/login',{username:this.username,password:this.password,}).then(response => {console.log(response.data);if(response.data.code==200){sessionStorage.setItem("accessToken",response.data.token)this.$router.push({ path: 'index'});}}).catch(error => {console.error(error);});}},}</script><style scoped></style>

index 页面

<template><div><button @click="test">请求受保护的接口</button></div></template><script>export default {data () {return {}},methods:{test(){const accessToken = sessionStorage.getItem('accessToken')let token = nullif(accessToken){token = accessToken}console.log(token)this.axios.post('http://localhost:8088/test',{},{headers:{accessToken:token}}).then(response => {// if(response.data.code==200){console.log(response.data);// }}).catch(error => {console.error(error);});},},}</script><style scoped></style>

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三、效果展示

1.点击登录后，后端给前端办法jwt令牌，前端将其存入sessionStorage中

2.点击【请求后端受保护的接口】按钮

3.继续多次点击【请求后端受保护的接口】按钮

可以看见，请求几次成功后，便显示令牌过期，这是因为，为了测试方便，我们颁发令牌时有效期设置的10秒

4.在请求接口中不传递Token

重新登录并点击【请求后端受保护的接口】按钮