接着上个章节来，上章节搭建好框架，并且测试也在页面取到数据。接下来实现web端，实现前后端交互，在前台进行注册登录以及后端***配置。实现简单的未登录拦截跳转到登录页面
上个章节传送门：使用spring boot完成增删改查--（一）查询
首先要实现web端需要在pom里引入jar包，前端用thymeleaf，所以在pom里添加以下内容
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency> 然后application-dev.yml里配置一下thymeleaf，如下
server:
port: 8888
spring:
datasource:
username: root
password: root
url: jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf-8&userSSL=true&serverTimezone=UTC
driver-class-name: com.mysql.cj.jdbc.Driver
thymeleaf:
cache: false
prefix: classpath:/templates/
suffix: .html
encoding: UTF-8
mode: html5
servlet:
content-type: text/html
mybatis:
mapper-locations: classpath:mapping/*Mapping.xml
type-aliases-package: com.example.entity
#showSql
logging:
level:
com:
example:
mapper: debug
下面写页面吧，在templates里创建需要的页面index.html、register.html、welcome.html。由于目标是实现功能，所以界面很简洁，样式统统省掉了，回归原始
register.html（注册页面）
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<html lang="en">
<head>
<meta charset="UTF-8">
<title>register</title>
</head>
<body>
<form action="/user/register" method="post">
请输入用户名--:<input type="text" name="userName" id="userName" /><br>
请你输入密码--:<input type="password" name="passWord" id="passWord" /><br>
<input type="submit" value="Register">
</form>
</body>
</html> index.html（登录页面）
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<form action="/user/loginUser" method="post">
请输入用户名--:<input type="text" name="userName" id="userName" /><br>
请你输入密码--:<input type="password" name="passWord" id="passWord" /><br>
<input type="submit" value="Login">
<a href="/user/toRegister">--注册--</a>
</form>
</body>
</html> welcome.html（退出登录页面，用于测试***）
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
注册或登录后才能看到的界面
<a href="/user/outUser">退出登录</a>
</body>
</html> 页面简洁（丑）到没朋友，下面后台实现逻辑，一套流程直接走起，不多解释了，直接放代码
controller下新建一个LoginController.java。我把注册登录退出登录方法全贴出来了
package com.example.controller;
import com.example.entity.User;
import com.example.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
/**
* Created with IntelliJ IDEA.
* User: LYP_PC
* Date: 2020/2/13
* Time: 18:09
* Description: No Description
*/
@Controller
@RequestMapping("/user")
public class LoginController {
@Autowired
private UserService userService;
// 跳转登录首页(登录页)
@RequestMapping("/toIndex")
public String show(){
return "index";
}
//登录操作
@ResponseBody
@RequestMapping("/loginUser")
public String login(User user, HttpServletRequest request){
String userName = user.getUserName();
String passWord = user.getPassWord();
User u1 = userService.login(userName,passWord);
if(u1 == null){
return "用户名或密码错误";
}else{
request.getSession().setAttribute("session_user",user); //登录成功后将用户放入session
return "登录成功";
}
}
//跳转注册页
@RequestMapping("/toRegister")
public String toRegister(){
return "register";
}
//注册操作
@RequestMapping("/register")
public String register(User user){
int su = userService.register(user);
if(su == 0){
System.out.println("----");
}
return "welcome";
}
//测试未登录拦截界面
@RequestMapping("/welcome")
public String welcome(){
return "welcome";
}
//退出登录
@RequestMapping("/outUser")
public void outUser(HttpServletRequest request, HttpServletResponse response) throws IOException {
request.getSession().removeAttribute("session_user");
response.sendRedirect("/user/toIndex");
}
}
UserService.java
package com.example.service;
import com.example.entity.User;
import com.example.mapper.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
/**
* Created with IntelliJ IDEA.
* User: LYP_PC
* Date: 2020/2/8
* Time: 17:55
* Description: No Description
*/
@Service
public class UserService {
@Autowired
UserMapper userMapper;
public User Sel(int id){
return userMapper.Sel(id);
}
public User login(String userName, String passWord) {
return userMapper.login(userName,passWord);
}
public int register(User user){
return userMapper.register(user);
}
}
UserMapper.java
package com.example.mapper;
import com.example.entity.User;
import org.springframework.stereotype.Repository;
/**
* Created with IntelliJ IDEA.
* User: LYP_PC
* Date: 2020/2/8
* Time: 17:57
* Description: No Description
*/
@Repository
public interface UserMapper {
User Sel(int id);
User login(String userName, String passWord);
int register(User user);
}
UserMapping.xml
<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.example.mapper.UserMapper">
<resultMap id="BaseResultMap" type="com.example.entity.User">
<result column="id" jdbcType="INTEGER" property="id"/>
<result column="userName" jdbcType="VARCHAR" property="userName"/>
<result column="passWord" jdbcType="VARCHAR" property="passWord"/>
<result column="realName" jdbcType="VARCHAR" property="realName"/>
</resultMap>
<select id="Sel" resultType="com.example.entity.User">
select * from user where id = #{id}
</select>
<select id="login" resultType="com.example.entity.User">
select * from user where userName = #{param1} and passWord = #{param2}
</select>
<insert id="register" parameterType="User">
insert into user (userName,password)values (#{userName},#{passWord})
</insert>
</mapper> 到这里就实现了登录注册了
其实注册登录也诶逻辑也很简单，就不多赘述了，接下来讲讲实现***功能（敲黑板，本章的重点）
首先在com.example下新建intercetor包，然后新建UserIntercetor.java实现HandlerInterceptor接口并重写方法，更多介绍都写在里面注释了
UserIntercetor.java
package com.example.intercetor;
import com.example.entity.User;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
/**
* Created with IntelliJ IDEA.
* User: LYP_PC
* Date: 2020/2/14
* Time: 17:17
* Description: No Description
*/
@Component
public class UserInterceptor implements HandlerInterceptor {
/*
* 进入cpntroller层之前拦截请求
* 返回值：表示是否将当前的请求拦截下来 false:拦截请求，请求别终止。 true:请求不被拦截，继续执行
* Object obj:表示被拦的请求的目标对象（controller中方法）
*/
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws IOException {
System.out.println("执行到了preHandle方法");
System.out.println(handler);
User user = (User) request.getSession().getAttribute("session_user");
if (user==null){
response.sendRedirect(request.getContextPath()+"/user/toIndex");//拦截后跳转的方法
System.out.println("已成功拦截并转发跳转");
return false;
}
System.out.println("合格不需要拦截，放行");
return true;
}
/*
* 处理请求完成后视图渲染之前的处理操作
* 通过ModelAndView参数改变显示的试图，或发现试图的方法
*
*/
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) {
System.out.println("执行了postHandle方法");
}
/*
* 视图渲染之后的操作
*/
@Override
public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3) throws Exception {
System.out.println("执行到了afterCompletion方法");
}
}
新建类SessionInterceptor实现WebMvcConfigurer接口来注册***
SessionInterceptor.java（类里的注释说明也很详细）
package com.example.intercetor;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import java.util.ArrayList;
import java.util.List;
/**
* Created with IntelliJ IDEA.
* User: Coffee君
* Date: 2020/2/15
* Time: 10:36
* Description: No Description
*/
@Configuration
public class SessionInterceptor implements WebMvcConfigurer {
/*
* 自定义***，添加拦截路径和排除拦截路径
* addPathPatterns();添加需要拦截的路径
* excludePathPatterns();添加不需要拦截的路径
*/
//添加***
@Override
public void addInterceptors(InterceptorRegistry registry){
List list = new ArrayList();
list.add("/user/toIndex");
list.add("/user/loginUser");
list.add("/user/toRegister");
list.add("/user/register");
registry.addInterceptor(new UserInterceptor()).addPathPatterns("/**").excludePathPatterns(list);
}
}
这个类中我放行了四个请求，一共写了五个请求，还有一个 "/user/welcome" 请求没有放行，就是用于测试***效果。
下面分别看下登录和未登录的拦截效果：
没有登录访问/user/welcome请求时（http://localhost:8888/user/welcome）
由于在session中没有获取到用户，所以UserIntercetor.java里的preHandle方法拦截了下来，并进行重定向到了/toIndex方法，打开了登录页面
再来看下登陆后直接访问/user/welcome请求时（http://localhost:8888/user/welcome）
可以看到页面可以访问打开welcome.html的，后台获取到session中的用户后也放行了。
本章节的任务至此也完成了。
Coffee君祝大家在学习的路上继续前行，一起努力。
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