spring boot 与自定义interceptor

时间 2019-12-19

标签 spring boot 自定义 interceptor 栏目 Spring 繁體版

原文原文链接

前面学习过过滤器, 可是过滤器是针对servlet的, 用在springmvc和spring boot里面, 功能上, 感受并非很好用.javascript

那这里来学习一下拦截器.html

一. 拦截器的执行顺序java

1. 目录jquery

2. 拦截器web

拦截器里面, 我加了三个(First,Two,Third), 可是内容都差很少.ajax

package org.elvin.boot.interceptor;

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

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

public class FirstInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
        System.out.println("FirstInterceptor preHandle");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
        System.out.println("FirstInterceptor postHandle");
    }

    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
        System.out.println("FirstInterceptor afterCompletion");
    }
}

preHandle 返回true, 才会继续下面的执行.spring

拦截器注册:浏览器

package org.elvin.boot.interceptor;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

@Configuration
public class RegisterInterceptor extends WebMvcConfigurerAdapter {
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new FirstInterceptor());
        registry.addInterceptor(new TwoInterceptor());
        registry.addInterceptor(new ThirdInterceptor());

        super.addInterceptors(registry);
    }
}

为了验证执行顺序, 这里使用了 thymeleaf, 而后在前台访问了我后台传过去的属性, 在访问的时候, 就会打印信息到控制台session

package org.elvin.boot.pojo;

public class Book {
    private String name ;

    public String getName() {
        System.out.println("view : Book'name is " + name);
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

Controller:mvc

package org.elvin.boot.Controller;

import org.elvin.boot.pojo.Book;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
@RequestMapping("first")
public class FirstController {
    private String controllerPath = "first/";

    @GetMapping("index")
    public String index(Model model){
        System.out.println("controller : FirstController index doing...");
        Book book = new Book();
        book.setName("spring boot");
        model.addAttribute("book", book);
        return controllerPath + "index";
    }
}

View:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8" />
    <title>Title</title>
</head>
<body>
    <h1 th:text="${book.name}"></h1>
</body>
</html>

在访问 localhost:8080/first/index 的时候, 就会在控制台输出响应的信息.

这样, 就能看出单个拦截器的执行顺序.

1. 在控制器方法执行以前, 执行的 preHandle 方法

2. 执行控制器的action方法

3. 执行完action, 解析view以前(若是有的话), 执行拦截器的 posthandle 方法

4. 解析view

5. 解析完以后, 执行 afterCompletion 方法

当注册多个拦截器的时候, 执行顺序, 如图上所示了.

二. 拦截器实现权限验证

一样的, 先加入权限拦截器

package org.elvin.boot.interceptor;

import org.elvin.boot.annotation.NoLogin;
import org.springframework.util.StringUtils;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

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

public class LoginInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handle) throws Exception {
        HandlerMethod method = (HandlerMethod ) handle;
        Class<?> controllerType = method.getBeanType();

        if(method.getMethodAnnotation(NoLogin.class) != null || controllerType.getAnnotation(NoLogin.class) != null){
            return true;
        }

        HttpSession session = request.getSession();
        String token = (String)session.getAttribute("token");
        if(!StringUtils.isEmpty(token)){
            return true;
        }

        response.sendRedirect("/login/index");
        return false;
    }

    @Override
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {

    }
}

而后注册权限拦截器

package org.elvin.boot.interceptor;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

@Configuration
public class RegisterInterceptor extends WebMvcConfigurerAdapter {
    @Override
    public void addInterceptors(InterceptorRegistry registry) {

        registry.addInterceptor(new LoginInterceptor());

        super.addInterceptors(registry);
    }
}

在控制器中加入登陆控制器, 提供登陆页面和注销方法

package org.elvin.boot.Controller;

import org.elvin.boot.annotation.NoLogin;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
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 javax.servlet.http.HttpSession;

@NoLogin
@Controller
@RequestMapping("login")
public class LoginController {

    @Autowired
    private HttpServletRequest request;

    @Autowired
    private HttpServletResponse response;

    private  String controllerPath = "login/";

    //@NoLogin
    @GetMapping("index")
    public String index(){
        HttpSession session = request.getSession();
        session.setAttribute("token", "token");
        return controllerPath + "index";
    }

    //@NoLogin
    @PostMapping("checkOut")
    @ResponseBody
    public String checkOut(){
        HttpSession session = request.getSession();
        session.setAttribute("token", null);

        return "ok";
    }
}

这里我作了一个免登陆注解, 能够加在Controller上, 也能够加在 action 上.

package org.elvin.boot.annotation;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target({ElementType.TYPE, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface NoLogin {
}

注解里面, 并不须要任何内容.

登陆页面(这里登陆页面只是为了注销用的, 因此访问过这个页面以后, 就表示登陆成功了).

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8"/>
    <title>Title</title>
</head>
<body>
<div class="container">
    <input type="button" value="注销" id="checkOut"/>
</div>


<script th:src="@{/js/jquery-1.11.1.js}"></script>
<script th:inline="javascript">
    $(function () {
        $(".container").delegate("#checkOut", "click", function () {
            $.ajax({
                url: [[@{/login/checkOut}]],
                type: 'post',
                data: {},
                success: function (res) {
                    if (res == "ok") {
                        alert("注销成功");
                    }
                }
            });
        });
    });
</script>
</body>
</html>

结果演示方式:

　在浏览器中, 先打开 http://localhost:8080/login/index 页面, 而后在新标签中访问 http://localhost:8080/first/index 页面.

　你会发现访问 first/index 的时候, 是能够访问的.

此时, 在login/index页面中, 点击注销按钮以后, 再刷新 first/index 页面, 就会直接跳去登陆页面.

spring boot 与 自定义interceptor

spring boot 与自定义interceptor