0%

SSM-12-拦截器

Posted on In , Views: Valine:
Symbols count in article: 6.3k Reading time ≈ 6 mins.

SSM-12-拦截器

  1. 权限验证
  2. 记录请求信息日志
  3. 判断用户是否登录

拦截器的配置

1
2
3
<mvc:interceptors>

</mvc:interceptors>
  • 全局拦截器
  • 拦截指定路径
  • 不需要拦截的路径
  • /hello 拦截以/hello结尾的路径

拦截器的执行流程

单个拦截器的执行流程

  1. 配置jar包
  2. 配置web.xml
  3. 配置控制器
1
2
3
4
5
6
7
8
9
10
11
12

@Controller
public class HelloController {
	/*
	 * 页面
	 */
	@RequestMapping("/hello")
	public String hello() {
		System.out.println("Hello");
		return "success";
	}
}
  1. 配置拦截器
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
package com.itheima.intercepter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

/**
 * @author NoOne dotaerday@gmail.com:
 * @version 创建时间：2020年3月12日 上午8:50:27 类说明
 */

/*
 * 实现了HandlerInterceptor的接口的自定义拦截器
 */
public class CustomeInterceptor implements HandlerInterceptor {
	@Override
	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object arg2) throws Exception {
		System.out.println("CustomInterceptor... preHandle");
		return true;
	}

	@Override
	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object arg2, ModelAndView arg3)
			throws Exception {
		System.out.println("CustomInterceptor..post");
	}

	@Override
	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object arg2, Exception arg3)
			throws Exception {
		System.out.println("CustomInterceptor..after");
	}

}

配置springmvc-config里的拦截器

1
2
3
4
5
6

<!-- 配置拦截器 -->
<mvc:interceptors>
	<!-- 使用bean直接定义拦截器 -->
	<bean class="com.itheima.intercepter.CustomeInterceptor"/>
</mvc:interceptors>

运行

1
2
3
4
CustomInterceptor... preHandle
Hello
CustomInterceptor..post
CustomInterceptor..after

确实是，先preHandle，然后post,然后after

多个拦截器的执行流程

复制两份interceptor

springmvc-config配置，

1
2
3
4
5
6
7
8
9
10
11
<!-- 拦截器1 -->
<mvc:interceptors>
	<mvc:interceptor>
		<mvc:mapping path="/**" />
		<bean class="com.itheima.intercepter.Interceptor1" />
	</mvc:interceptor>
	<mvc:interceptor>
		<mvc:mapping path="/hello" />
		<bean class="com.itheima.intercepter.Interceptor2" />
	</mvc:interceptor>
</mvc:interceptors>

这里我出了一个错，interceptors跟interceptor不一样，差点就报错了，在mvc:interceptors里配多个拦截器

执行结果

1
2
3
4
5
6
7
CustomInterceptor1... preHandle
CustomInterceptor2... preHandle
Hello
CustomInterceptor2..post
CustomInterceptor1..post
CustomInterceptor2..after
CustomInterceptor1..after

类似于栈的结构，首先1压栈，2压栈，然后将2出栈，1 出栈，最后释放空间

拦截器的应用—用户登录权限验证

控制器

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
@Controller
public class UserController {
	@RequestMapping(value="/login", method=RequestMethod.GET)
	public String toLogin() {
		return "login";
	}
	
	/*
	 * 登录
	 */
	@RequestMapping(value="/login",method=RequestMethod.POST)
	public String login(User user, Model model, HttpSession session) {
		//获取用户密码
		String username = user.getUsername();
		String password = user.getPassword();
		if(username != null && username.equals("xiaoming") && password.equals("123456")) {
			session.setAttribute("USER_SESSION", user);
			//重定向到主页面的跳转方法
			return "redirect:main";
		}
		model.addAttribute("msg", "用户名或者密码错误");
		return "login";
	}
	
	
	/*
	 * 向用户主页面跳转
	 */
	@RequestMapping("/main")
	public String toMain() {
		return "main";
	}
	
	@RequestMapping("/Logout")
	public String logout(HttpSession session) {
		//清除session
		session.invalidate();
		return "redirect:login";
	}
}

拦截器

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
package com.itheima.intercepter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import com.itheima.po.User;

/**
* @author NoOne dotaerday@gmail.com:
* @version 创建时间：2020年3月12日 上午9:30:10
* 类说明
*/

public class LoginInterceptor implements HandlerInterceptor {
	@Override
	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object arg2) throws Exception {
		//获取的请求的URL
		String url = request.getRequestURI();
		//URL除了login.jsp是公开的，其余都拦截
		if(url.indexOf("/login") >= 0) {
			return true;
		}
		HttpSession session = request.getSession();
		User user = (User) session.getAttribute("USER_SESSION");
		//如果有则返回true
		if(user != null) {
			return true;
		}
		request.setAttribute("msg", "您还没有登录，请先登录!");
		request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request, response);
		return false;
	}

	@Override
	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object arg2, ModelAndView arg3)
			throws Exception {
		
	}

	@Override
	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object arg2, Exception arg3)
			throws Exception {
		
	}

}

配置文件

1
2
3
4
5
6
7
8
9
10
11
12
13
14
<mvc:interceptors>
	<mvc:interceptor>
		<mvc:mapping path="/**" />
		<bean class="com.itheima.intercepter.Interceptor1" />
	</mvc:interceptor>
	<mvc:interceptor>
		<mvc:mapping path="/hello" />
		<bean class="com.itheima.intercepter.Interceptor2" />
	</mvc:interceptor>
	<mvc:interceptor>
		<mvc:mapping path="/**" />
		<bean class="com.itheima.intercepter.LoginInterceptor" />
	</mvc:interceptor>
</mvc:interceptors>

main.jsp

1
2
3
4
5
6
7
8
9
10
11
12
13
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>系统主页</title>
</head>
<body>
	当前用户: ${USER_SESSION.username }
	<a href="${pageContext.request.contextPath }/Logout"/>
</body>
</html>

login.jsp

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>登录页面</title>
</head>
<body>
    ${msg}
	<form action="${pageContext.request.contextPath }/login" 
            method="POST">
		用户名：<input type="text" name="username"/><br />
		密&nbsp;&nbsp;&nbsp;码：
                 <input type="password" name="password"/><br />
		<input type="submit" value="登录" />
	</form>
</body>
</html>

又出现了好多错

  1. 拦截器配置错误，然后报 root 的错误
  2. 拦截器名称配置错误，报class not found

测试结果

1
2
3
4
5
6
CustomInterceptor1... preHandle
CustomInterceptor1..post
CustomInterceptor1..after
CustomInterceptor1... preHandle
CustomInterceptor1..post
CustomInterceptor1..after

本文作者：NoOne
本文地址： https://noonegroup.xyz/posts/12321d7f/
版权声明：转载请注明出处！