• 登录认证，登录校验

    一、基础登录功能

     1.Controller层

    1. import com.itheima.pojo.Emp;
    2. import com.itheima.pojo.Result;
    3. import com.itheima.service.EmpService;
    4. import lombok.extern.slf4j.Slf4j;
    5. import org.springframework.beans.factory.annotation.Autowired;
    6. import org.springframework.web.bind.annotation.PostMapping;
    7. import org.springframework.web.bind.annotation.RequestBody;
    8. import org.springframework.web.bind.annotation.RestController;
    9.  
    10. @Slf4j
    11. @RestController
    12. public class LoginController {
    13.     @Autowired
    14.     private EmpService empService;
    15.  
    16.     @PostMapping("/login")
    17.     public Result login(@RequestBody Emp emp){
    18.         log.info ( "登录用户名：{}，密码：{}",emp );
    19.     Emp e =empService.login(emp);
    20.         return e!=null?Result.success ():Result.error ( "用户名或密码错误" );
    21.  
    22.     }
    23. }

    2.Service层

    1.     @Override
    2.     public Emp login(Emp emp) {
    3.         return empMapper.getByusernameAndPassword(emp);
    4.     }
    5. }

    3.Mapper层

    1.  /**
    2.      * 根据用户名密码查询员工
    3.      * @param emp
    4.      * @return
    5.      */
    6.  
    7.     @Select ( "select * from emp where username=#{username} and password=#{password}")
    8.     Emp getByusernameAndPassword(Emp emp);

    二、登录校验

    1.会话技术

    1.会话跟踪方案对比

    1.  
    2. import com.itheima.pojo.Result;
    3. import lombok.extern.slf4j.Slf4j;
    4. import org.springframework.web.bind.annotation.GetMapping;
    5. import org.springframework.web.bind.annotation.RestController;
    6.  
    7. import javax.servlet.http.Cookie;
    8. import javax.servlet.http.HttpServletRequest;
    9. import javax.servlet.http.HttpServletResponse;
    10. import javax.servlet.http.HttpSession;
    11.  
    12. /**
    13.  * HttpSession演示
    14.  */
    15. @Slf4j
    16. @RestController
    17. public class SessionController {
    18.  
    19.     //设置Cookie
    20.     @GetMapping("/c1")
    21.     public Result cookie1(HttpServletResponse response){
    22.         response.addCookie(new Cookie("login_username","itheima")); //设置Cookie/响应Cookie
    23.         return Result.success();
    24.     }
    25.  
    26.     //获取Cookie
    27.     @GetMapping("/c2")
    28.     public Result cookie2(HttpServletRequest request){
    29.         Cookie[] cookies = request.getCookies();
    30.         for (Cookie cookie : cookies) {
    31.             if(cookie.getName().equals("login_username")){
    32.                 System.out.println("login_username: "+cookie.getValue()); //输出name为login_username的cookie
    33.             }
    34.         }
    35.         return Result.success();
    36.     }
    37.  
    38.  
    39.  
    40.     @GetMapping("/s1")
    41.     public Result session1(HttpSession session){
    42.         log.info("HttpSession-s1: {}", session.hashCode());
    43.  
    44.         session.setAttribute("loginUser", "tom"); //往session中存储数据
    45.         return Result.success();
    46.     }
    47.  
    48.     @GetMapping("/s2")
    49.     public Result session2(HttpServletRequest request){
    50.         HttpSession session = request.getSession();
    51.         log.info("HttpSession-s2: {}", session.hashCode());
    52.  
    53.         Object loginUser = session.getAttribute("loginUser"); //从session中获取数据
    54.         log.info("loginUser: {}", loginUser);
    55.         return Result.success(loginUser);
    56.     }
    57. }

    2.JWT令牌技术

    1. /**
    2.      * 测试Jwt令牌的生成
    3.      */
    4.     @Test
    5.     public void testGenJwt(){
    6.         Map claims=new HashMap<> ();
    7.         claims.put ( "id",1 );
    8.         claims.put ( "name","TOM" );
    9.         String jwt = Jwts.builder ()
    10.                 .signWith ( SignatureAlgorithm.HS256, "itheima" )//签名算法
    11.                 .setClaims ( claims )//自定义内容（载荷）
    12.                 .setExpiration ( new Date ( System.currentTimeMillis ()  ) )
    13. //                .setExpiration ( new Date ( System.currentTimeMillis () + 3600 * 1000 ) )//设置令牌的有效期为1个小时
    14.                 .compact ();//返回一个jwt令牌
    15.         System.out.println (jwt);
    16.     }

    1.生成JWT令牌

    2.令牌解析

    1.     @Test
    2.     public void testPrasejwt(){
    3.         Claims claims = Jwts.parser ()
    4.                 .setSigningKey ( "itheima" )
    5.                 .parseClaimsJws ( "eyJhbGciOiJIUzI1NiJ9.eyJuYW1lIjoiVE9NIiwiaWQiOjEsImV4cCI6MTY5NzAwOTgwN30.9iduxbB4vpQLGs3anczG-spuQdT5f_3BR6aHYYHop3M" )
    6.                 .getBody ();
    7.         System.out.println ( claims );
    8.     }

    3.登陆后下发令牌

    1.jwtUtils类
    1. import io.jsonwebtoken.Claims;
    2. import io.jsonwebtoken.Jwts;
    3. import io.jsonwebtoken.SignatureAlgorithm;
    4. import java.util.Date;
    5. import java.util.Map;
    6.  
    7. public class JwtUtils {
    8.  
    9.     private static String signKey = "itheima";
    10.     private static Long expire = 43200000L;
    11.  
    12.     /**
    13.      * 生成JWT令牌
    14.      * @param claims JWT第二部分负载 payload 中存储的内容
    15.      * @return
    16.      */
    17.     public static String generateJwt(Map claims){
    18.         String jwt = Jwts.builder()
    19.                 .addClaims(claims)
    20.                 .signWith(SignatureAlgorithm.HS256, signKey)
    21.                 .setExpiration(new Date(System.currentTimeMillis() + expire))
    22.                 .compact();
    23.         return jwt;
    24.     }
    25.  
    26.     /**
    27.      * 解析JWT令牌
    28.      * @param jwt JWT令牌
    29.      * @return JWT第二部分负载 payload 中存储的内容
    30.      */
    31.     public static Claims parseJWT(String jwt){
    32.         Claims claims = Jwts.parser()
    33.                 .setSigningKey(signKey)
    34.                 .parseClaimsJws(jwt)
    35.                 .getBody();
    36.         return claims;
    37.     }
    38. }
    2.Controller层
    1. import com.itheima.pojo.Emp;
    2. import com.itheima.pojo.Result;
    3. import com.itheima.service.EmpService;
    4. import com.itheima.utils.JwtUtils;
    5. import lombok.extern.slf4j.Slf4j;
    6. import org.springframework.beans.factory.annotation.Autowired;
    7. import org.springframework.web.bind.annotation.PostMapping;
    8. import org.springframework.web.bind.annotation.RequestBody;
    9. import org.springframework.web.bind.annotation.RestController;
    10.  
    11. import java.util.HashMap;
    12. import java.util.Map;
    13.  
    14. @Slf4j
    15. @RestController
    16. public class LoginController {
    17.     @Autowired
    18.     private EmpService empService;
    19.  
    20.     @PostMapping("/login")
    21.     public Result login(@RequestBody Emp emp){
    22.         log.info ( "登录用户名：{}，密码：{}",emp );
    23.     Emp e =empService.login(emp);
    24.     //登陆成功，生成令牌，下发令牌
    25.     if (e!=null){
    26.         Map claims=new HashMap<> ();
    27.         claims.put ( "id",e.getId () );
    28.         claims.put ( "name",e.getUsername () );
    29.         claims.put ( "username",e.getUsername () );
    30.         String jwt = JwtUtils.generateJwt ( claims );//jwt 包含了当前登录的员工信息
    31.         return Result.success (jwt);//下发jwt令牌
    32.     }
    33.  
    34.     //登录失败，返回错误信息
    35.         return Result.error ( "用户名或密码错误" );
    36.  
    37.     }
    38. }

    三、过滤器 -Filter

    1.入门程序

    1. import javax.servlet.*;
    2. import javax.servlet.annotation.WebFilter;
    3. import java.io.IOException;
    4. @WebFilter(urlPatterns = "/*")
    5. public class DemoFilter implements Filter {
    6.     @Override //初始化方法只调用一次
    7.     public void init(FilterConfig filterConfig) throws ServletException {
    8.         System.out.println ("初始化方法被调用了");
    9.     }
    10.  
    11.     @Override   //拦截到请求之后调用
    12.     public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain chain) throws IOException, ServletException {
    13.         System.out.println ("拦截到了请求");
    14.         chain.doFilter ( servletRequest,servletResponse );//放行
    15.     }
    16.  
    17.     @Override //销毁方法，只调用一次
    18.     public void destroy() {
    19.         System.out.println ("销毁方法被调用了");
    20.     }
    21. }

    2.Filter详解

    1.Filter执行流程

    2.过滤器的拦截路径

    3.过滤器链

    3.Filter完成登录校验

    1.LoginCheckFilter

    1. import com.alibaba.fastjson.JSONObject;
    2. import com.itheima.pojo.Result;
    3. import com.itheima.utils.JwtUtils;
    4. import lombok.extern.slf4j.Slf4j;
    5. import org.springframework.util.StringUtils;
    6.  
    7. import javax.servlet.*;
    8. import javax.servlet.annotation.WebFilter;
    9. import javax.servlet.http.HttpServletRequest;
    10. import javax.servlet.http.HttpServletResponse;
    11. import java.io.IOException;
    12.  
    13. @Slf4j
    14. @WebFilter(urlPatterns = "/*")
    15. public class LoginCheckFilter implements Filter {
    16.     @Override
    17.     public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
    18.  
    19.         HttpServletRequest req = (HttpServletRequest) servletRequest;
    20.         HttpServletResponse resp = (HttpServletResponse) servletResponse;
    21.     //1.获取请求url
    22.         String url = req.getRequestURI ().toString ();
    23.         log.info ( "请求的url：{}",url );
    24.     //2.判断请求url中是否包含login，如果包含，说明是登陆操作，放行
    25.         if (url.contains ( "login" )){
    26.             log.info ("登陆操作，放行...");
    27.             filterChain.doFilter (servletRequest,servletResponse  );
    28.             return;
    29.         }
    30.     //3.获取请求头的令牌（token）
    31.         String jwt = req.getHeader ( "token" );
    32.  
    33.     //4.判断令牌是否存在，如果不存在，返错误结果（未登录）
    34.     if (!StringUtils.hasLength ( jwt )){
    35.         log.info ( "请求头token为空，返回未登录的信息" );
    36.         Result error = Result.error ( "NOT_LOGIN" );
    37.         //手动转换Josn数据
    38.         String notLogin = JSONObject.toJSONString ( error );
    39.         resp.getWriter ().write ( notLogin );
    40.         return;
    41.     }
    42.     //5.解析token，如果解析失败，返回错误结果（未登录）
    43.         try {
    44.             JwtUtils.parseJWT ( jwt );
    45.         } catch (Exception e) {
    46.             e.printStackTrace ();
    47.             log.info ( "解析令牌失败，返回未登录错误信息" );
    48.             Result error = Result.error ( "NOT_LOGIN" );
    49.             //手动转换Josn数据
    50.             String notLogin = JSONObject.toJSONString ( error );
    51.             resp.getWriter ().write ( notLogin );
    52.             return;
    53.         }
    54.         //6.放行
    55.         log.info ( "令牌合法，放行" );
    56.         filterChain.doFilter ( servletRequest,servletResponse );
    57.     }
    58. }

    2.手动将字符串转换为JSON格式数据

    1.  //手动转换Josn数据
    2.         String notLogin = JSONObject.toJSONString ( error );
    3.         resp.getWriter ().write ( notLogin );

    3.引入依赖

    1.         <dependency>
    2.             <groupId>com.alibabagroupId>
    3.             <artifactId>fastjsonartifactId>
    4.             <version>2.0.32version>
    5.         dependency>

    四、拦截器

    1.拦截器的基本使用

    1.定义拦截器

    1. import org.springframework.stereotype.Component;
    2. import org.springframework.web.servlet.HandlerInterceptor;
    3. import org.springframework.web.servlet.ModelAndView;
    4.  
    5. import javax.servlet.http.HttpServletRequest;
    6. import javax.servlet.http.HttpServletResponse;
    7. @Component
    8. public class LoginCheckInterceptor implements HandlerInterceptor {
    9.     @Override//目标资源方法运行前运行，返回true 放行
    10.     public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
    11.         System.out.println ("preHandle...");
    12.         return true;
    13.     }
    14.  
    15.     @Override//目标资源方法运行后运行
    16.     public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
    17.         System.out.println ("postHandle.....");
    18.     }
    19.  
    20.     @Override//视图渲染完毕后，最后运行
    21.     public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
    22.         System.out.println ("afterCompletion...");
    23.     }
    24. }

    2.配置拦截器

    1. import com.itheima.interceptor.LoginCheckInterceptor;
    2. import org.springframework.beans.factory.annotation.Autowired;
    3. import org.springframework.context.annotation.Configuration;
    4. import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
    5. import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
    6. @Configuration//配置类
    7. public class WebConfig implements WebMvcConfigurer {
    8.     @Autowired
    9.     private LoginCheckInterceptor loginCheckInterceptor;
    10.     @Override
    11.     public void addInterceptors(InterceptorRegistry registry) {
    12.         registry.addInterceptor ( loginCheckInterceptor ).addPathPatterns ( "/**" );
    13.     }
    14. }

    2.拦截路径，执行流程

     3.拦截器完成登录校验

    1. import com.alibaba.fastjson.JSONObject;
    2. import com.itheima.pojo.Result;
    3. import com.itheima.utils.JwtUtils;
    4. import lombok.extern.slf4j.Slf4j;
    5. import org.springframework.util.StringUtils;
    6.  
    7. import javax.servlet.*;
    8. import javax.servlet.annotation.WebFilter;
    9. import javax.servlet.http.HttpServletRequest;
    10. import javax.servlet.http.HttpServletResponse;
    11. import java.io.IOException;
    12.  
    13. @Slf4j
    14. //@WebFilter(urlPatterns = "/*")
    15. public class LoginCheckFilter implements Filter {
    16.     @Override
    17.     public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
    18.  
    19.         HttpServletRequest req = (HttpServletRequest) servletRequest;
    20.         HttpServletResponse resp = (HttpServletResponse) servletResponse;
    21.     //1.获取请求url
    22.         String url = req.getRequestURI ().toString ();
    23.         log.info ( "请求的url：{}",url );
    24.     //2.判断请求url中是否包含login，如果包含，说明是登陆操作，放行
    25.         if (url.contains ( "login" )){
    26.             log.info ("登陆操作，放行...");
    27.             filterChain.doFilter (servletRequest,servletResponse  );
    28.             return;
    29.         }
    30.     //3.获取请求头的令牌（token）
    31.         String jwt = req.getHeader ( "token" );
    32.  
    33.     //4.判断令牌是否存在，如果不存在，返错误结果（未登录）
    34.     if (!StringUtils.hasLength ( jwt )){
    35.         log.info ( "请求头token为空，返回未登录的信息" );
    36.         Result error = Result.error ( "NOT_LOGIN" );
    37.         //手动转换Josn数据
    38.         String notLogin = JSONObject.toJSONString ( error );
    39.         resp.getWriter ().write ( notLogin );
    40.         return;
    41.     }
    42.     //5.解析token，如果解析失败，返回错误结果（未登录）
    43.         try {
    44.             JwtUtils.parseJWT ( jwt );
    45.         } catch (Exception e) {
    46.             e.printStackTrace ();
    47.             log.info ( "解析令牌失败，返回未登录错误信息" );
    48.             Result error = Result.error ( "NOT_LOGIN" );
    49.             //手动转换Josn数据
    50.             String notLogin = JSONObject.toJSONString ( error );
    51.             resp.getWriter ().write ( notLogin );
    52.             return;
    53.         }
    54.         //6.放行
    55.         log.info ( "令牌合法，放行" );
    56.         filterChain.doFilter ( servletRequest,servletResponse );
    57.     }
    58. }

    五、异常处理

    1. import com.itheima.pojo.Result;
    2. import org.springframework.web.bind.annotation.ExceptionHandler;
    3. import org.springframework.web.bind.annotation.RestControllerAdvice;
    4.  
    5. /**
    6.  * 全局异常处理器
    7.  */
    8. @RestControllerAdvice
    9. public class GlobalExceptionHandler {
    10.     @ExceptionHandler(Exception.class)//捕获异常的类型
    11.  public Result ex(Exception exception){
    12.         return Result.error ( "对不起操作失败，请联系管理员" );
    13.     }
    14. }

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  • 原文地址：https://blog.csdn.net/m0_64703222/article/details/133766996