相应数据和结果视图

返回值分类

1.string
**
创建项目，参照第一天

public class User implements Serializable {
    private String username;
    private String password;
    private Integer age;
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    @Override
    public String toString() {
        return "User{" +
                "username='" + username + '\'' +
                ", password='" + password + '\'' +
                ", age=" + age +
                '}';
    }
}

@Controller
@RequestMapping("/user")
public class UserController {
    @RequestMapping("/testString")
    public String testString(Model model){
        System.out.println("testString方法执行了。。。");
        //模拟从数据库中查询出User对象
        User user = new User();
        user.setUsername("美美");
        user.setPassword("123");
        user.setAge(30);
        //model对象
        model.addAttribute("user",user);
        return "success";
    }
}

<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<h3>执行成功</h3>
${user.username}
${user.password}
</body>
</html>

<body>
<a href="user/testString">testString</a>
</body>

jsp中直接取值

2.void
不返回success页面

默认

    @RequestMapping("/testVoid")
    public void testVoid(){
        System.out.println("testVoid方法执行了。。。");
    }

<a href="user/testVoid">testVoid</a>

默认寻找testVoid.jsp

2.编写请求转发程序

    @RequestMapping("/testVoid")
    public void testVoid(HttpServletRequest request, HttpServletResponse response) throws Exception {
        System.out.println("testVoid方法执行了。。。");
        //编写请求转发的程序
        request.getRequestDispatcher("/WEB-INF/pages/success.jsp").forward(request,response);
        return;//如果后面有代码，return可以使其停止
    }

    @RequestMapping("/testVoid")
    public void testVoid(HttpServletRequest request, HttpServletResponse response) throws Exception {
        System.out.println("testVoid方法执行了。。。");
        //重定向,相当与重新发一个请求
        response.sendRedirect(request.getContextPath()+"/index.jsp");
        return;//如果后面有代码，return可以使其停止
    }

直接响应

 @RequestMapping("/testVoid")
 public void testVoid(HttpServletRequest request, HttpServletResponse response) throws Exception {
     System.out.println("testVoid方法执行了。。。");

     //设置中文乱码
     response.setCharacterEncoding("utf-8");
     response.setContentType("text/html;charset=utf-8");

     //直接响应
     response.getWriter().print("哈哈");
     return;//如果后面有代码，return可以使其停止
 }

3. ModelAndView
ModelAndView对象是spring提供的一个对象，可以用来调整具体的jsp视图，和string类似，string的底层实现就是通过modelandview实现的

    @RequestMapping("/testModelAndView")
    public ModelAndView testModelAndView(){
        //创建modelandview
        ModelAndView mv = new ModelAndView();
        System.out.println("testModelAndView方法执行了。。。");
        //模拟从数据库中查询出User对象
        User user = new User();
        user.setUsername("美美");
        user.setPassword("123");
        user.setAge(30);
        //把user对象存储到mv对象中，也会把user对象存入到request对象
        mv.addObject("user",user);
        //跳转到哪个页面
        mv.setViewName("success");
        return mv;
    }

<a href="user/testModelAndView">testModelAndView</a>

关键字转发和重定向

无法使用视图解析器

1. forward和redirect转发

<a href="user/testForwardOrRedirect">testForwardOrRedirect</a>

    @RequestMapping("/testForwardOrRedirect")
    public String testForwardOrRedirect(){
        System.out.println("testForwardOrRedirect方法执行了。。。");
        //请求转发
        //return "forward:/WEB-INF/pages/success.jsp";
        //重定向,底层已默认加入了项目名
        return "redirect:/index.jsp";
    }

ResponseBody响应json数据

发送AJAX请求

过滤静态资源

前端控制器会拦截所有资源，使css,js,images不被拦截

在springmvc.xml中配置

<!--前端控制器，哪些静态资源不拦截-->
    <mvc:resources location="/js/" mapping="/js/**"/>
    <mvc:resources location="/images/" mapping="/images/**"/>
    <mvc:resources location="/css/" mapping="/css/**"/>

在response.jsp中添加js

    <script>
        //页面加载，绑定单击事件
        $(function (){
            $("#btn").click(function () {
              alert("hello btn");
            });
        });
    </script>

<br/>
<button id="btn">发送ajax的请求</button>

2.响应json格式数据

    /**
     * 模拟异步请求响应
     */
    @RequestMapping("/testAjax")
    public @ResponseBody User testAjax(@RequestBody User user){
        System.out.println("testAjax方法执行了。。。");
        //客户端发送AJAX的请求，传的是json字符串，后端把json字符串封装到user对象中
        System.out.println(user);
        //做响应，模拟查询数据库
        user.setUsername("haha");
        user.setAge(40);
        //响应
        return user;
    }

 $(function (){
            $("#btn").click(function () {
              //alert("hello btn");
                //发送ajax请求
                $.ajax({
                    url:"user/testAjax",
                    ContentType:"application/json;charset=UTF-8",
                    data:'{"username":"hehe","password":"123","age":30}',
                    dataType:"json",
                    type:"post",
                    success:function(data) {
                        //data服务器响应json的数据，进行解析
                        alert(data);
                        alert(data.username);
                        alert(data.password);
                        alert(data.age);
                    }
                });
            });

springMVC实现文件上传

springMVC上传

index.jsp

<%--
  Created by IntelliJ IDEA.
  User: 御琼
  Date: 2019/6/17
  Time: 14:54
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
       <h3>传统文件上传 </h3>
    <form action="user/fileupload1" method="post" enctype="multipart/form-data">
    选择文件：<input type="file" name="upload" /><br/>
    <input type="submit" value="上传"/><br/>
    </form>

    <h3>springMVC文件上传 </h3>
    <form action="user/fileupload2" method="post" enctype="multipart/form-data">
        选择文件：<input type="file" name="upload" /><br/>
        <input type="submit" value="上传"/><br/>
    </form>

</body>
</html>

package cn.itcast.controller;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletRequest;
import java.io.File;
import java.util.List;
import java.util.UUID;

/**
 * @author yuqiong
 * @date 2019/6/17-14:55
 */
@Controller
@RequestMapping("/user")
public class UserController {

    /**
     * springMVC文件上传
     * @return
     */
    @RequestMapping("/fileupload2")
    public String fileupload2(HttpServletRequest request , MultipartFile upload) throws Exception {
        System.out.println("springmvc文件上传。。。");
        //使用fileupload
        String path = request.getSession().getServletContext().getRealPath("/uploads/");
        System.out.println(path +"springmvc");
        //判断，该路径是否存在
        File file = new File(path);
        if (!file.exists()){
            //创建文件夹
            file.mkdirs();
        }

        //说明上传文件项
        //获取上传文件的名称
        String filename = upload.getOriginalFilename();
        //把文件名称设为唯一值
        String uuid = UUID.randomUUID().toString().replace("-", "");
        filename = uuid + "_" + filename;
        //完成文件上传
        upload.transferTo(new File(path, filename));

        return "success";
    }

    /**
     * 传统文件上传
     * @return
     */
    @RequestMapping("/fileupload1")
    public String fileupload1(HttpServletRequest request) throws Exception {
        System.out.println("文件上传。。。");
        //使用fileupload
        String path = request.getSession().getServletContext().getRealPath("/uploads/");
        System.out.println(path + "传统");
        //判断，该路径是否存在
        File file = new File(path);
        if (!file.exists()){
            //创建文件夹
            file.mkdirs();
        }

        //解析request对象，获取上传文件项
        DiskFileItemFactory factory = new DiskFileItemFactory();
        ServletFileUpload upload = new ServletFileUpload(factory);
        //解析request
        List<FileItem> items = upload.parseRequest(request);
        //遍历
        for (FileItem item : items){
            //进行判断，当前item对象是否是上传文件项
            if (item.isFormField()){
                //说明普通表单项
            }else {
                //说明上传文件项
                //获取上传文件的名称
                String filename = item.getName();
                //把文件名称设为唯一值
                String uuid = UUID.randomUUID().toString().replace("-", "");
                filename = uuid + "_" + filename;
                //完成文件上传
                item.write(new File(path,filename));
                //删除临时文件
                item.delete();
            }
        }
        return "success";
    }
}

springmvc.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd">

    <!-- 开启注解扫描 -->
    <context:component-scan base-package="cn.itcast"/>

    <!-- 视图解析器对象 -->
    <bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/pages/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

    <!--前端控制器，哪些静态资源不拦截-->
    <mvc:resources location="/css/" mapping="/css/**"/>
    <mvc:resources location="/images/" mapping="/images/**"/>
    <mvc:resources location="/js/" mapping="/js/**"/>

    <!--配置文件解析器对象-->
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <property name="maxUploadSize" value="10485760" />
    </bean>

    <!-- 开启SpringMVC框架注解的支持 -->
    <mvc:annotation-driven />

</beans>

pom.xml

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>cn.itcast</groupId>
  <artifactId>springmvc_day02_02_fileupload</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>springmvc_day02_02_fileupload Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
    <spring.version>5.0.2.RELEASE</spring.version>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>servlet-api</artifactId>
      <version>2.5</version>
      <scope>provided</scope>
    </dependency>

    <dependency>
      <groupId>javax.servlet.jsp</groupId>
      <artifactId>jsp-api</artifactId>
      <version>2.0</version>
      <scope>provided</scope>
    </dependency>

    <dependency>
      <groupId>commons-fileupload</groupId>
      <artifactId>commons-fileupload</artifactId>
      <version>1.3.1</version>
    </dependency>
    <dependency>
      <groupId>commons-io</groupId>
      <artifactId>commons-io</artifactId>
      <version>2.4</version>
    </dependency>

    <dependency>
      <groupId>com.sun.jersey</groupId>
      <artifactId>jersey-core</artifactId>
      <version>1.18.1</version>
    </dependency>
    <dependency>
      <groupId>com.sun.jersey</groupId>
      <artifactId>jersey-client</artifactId>
      <version>1.18.1</version>
    </dependency>


  </dependencies>

  <build>
    <finalName>springmvc_day02_02_fileupload</finalName>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-war-plugin</artifactId>
          <version>3.2.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

web.xml

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
  <display-name>Archetype Created Web Application</display-name>
  <servlet>
    <servlet-name>dispatcherServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:springmvc.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>dispatcherServlet</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>

  <!--配置解决中文乱码的过滤器-->
  <filter>
    <filter-name>characterEncodingFilter</filter-name>
    <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
    <init-param>
      <param-name>encoding</param-name>
      <param-value>UTF-8</param-value>
    </init-param>
  </filter>
  <filter-mapping>
    <filter-name>characterEncodingFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>
</web-app>

跨服务器上传

搭建图片服务器

配置图片服务器

再新建一个module,和其他项目一样，再新建一个文件夹

最后将服务器与fileupload工程绑定

springMVC的异常处理

不会将错误直接展示给用户，而是返回一个错误提示页面

配置项目

其他地方相同，springmvc.xml中删除配置文件解析器对象，因为没有导包会报错

index.jsp

<%--
  Created by IntelliJ IDEA.
  User: 御琼
  Date: 2019/6/18
  Time: 21:25
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
      <h3>异常处理</h3>
      <a href="user/testException">异常处理</a>
</body>
</html>

success.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<h3>执行成功了。。。</h3>
</body>
</html>

实验
cn.itcast.controller.UserController.java

@Controller
@RequestMapping("/user")
public class UserController {
    @RequestMapping("/testException")
    public String testException(){
        System.out.println("testException执行了。。。");
        //模拟异常
        int a = 10/0;
        return "success";
    }
}

FireShot Capture 004 - HTTP Status 500 – Internal Server Error - localhost.png

自定义异常类 ```java package cn.itcast.exception;

/**

自定义异常类
@author yuqiong
@date 2019/6/18-21:45 */ public class SysException extends Exception { //存储提示信息 private String message;

//构造方法，必须传入值 public SysException(String message) {
```
 this.message = message;
```
}

@Override public String getMessage() {
```
 return message;
```
}

public void setMessage(String message) {
```
 this.message = message;
```
} } ```

改写UserController

package cn.itcast.controller;

import cn.itcast.exception.SysException;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

/**
 * @author yuqiong
 * @date 2019/6/18-21:27
 */
@Controller
@RequestMapping("/user")
public class UserController {
    @RequestMapping("/testException")
    public String testException() throws SysException {
        System.out.println("testException执行了。。。");

        try {
            //模拟异常
            int a = 10/0;
        } catch (Exception e) {
            //打印异常信息
            e.printStackTrace();
            //抛出自定义异常信息
            throw new SysException("查询所有用户出现错误。。。");
        }

        return "success";
    }
}

2.编写异常处理器

package cn.itcast.exception;

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

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

/**
 * 异常处理器
 * @author yuqiong
 * @date 2019/6/18-22:00
 */
public class SysExceptionResolver implements HandlerExceptionResolver {
    /**
     * 处理异常业务逻辑
     * @param httpServletRequest
     * @param httpServletResponse
     * @param o
     * @param e
     * @return
     */
    @Override
    public ModelAndView resolveException(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) {
        //获取到异常对象
        SysException sysException = null;
        if (e instanceof SysException){
            sysException = (SysException) e;
        }else {
            sysException = new SysException("系统正在维护。。。");
        }
        //创建ModelAndView对象
        ModelAndView mv = new ModelAndView();
        mv.addObject("errorMsg",sysException.getMessage());
        mv.setViewName("error");
        return mv;
    }
}

springmvc.xml中配置异常处理器

    <!--配置异常处理器-->
    <bean id="SysExceptionResolver" class="cn.itcast.exception.SysExceptionResolver"></bean>

编写异常页面error

<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
${errorMsg}
</body>
</html>

效果

testException执行了。。。
java.lang.ArithmeticException: / by zero
    at cn.itcast.controller.UserController.testException(UserController.java:20)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:871)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:777)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:978)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:870)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:855)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:200)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:668)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:834)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1415)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)

springMVC的拦截器

拦截器与过滤器的区别

过滤器：是servlet规范中的一部分，任意Javaweb工程都可以使用，在url-pattern中配置/*之后，可以对所要访问的资源拦截。
过滤器：是springMVC框架自己的，只使用springMVC框架的工程才可以使用，只拦截控制器方法，jsp,html,css,image,js是不会拦截的。

自定义拦截器

必须实现HandlerInterceptor接口

新建配置新项目，步骤同上

拦截器

package cn.itcast.interceptor;

import org.springframework.web.servlet.HandlerInterceptor;

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

/**
 * 自定义拦截器
 * @author yuqiong
 * @date 2019/6/19-12:25
 */
public class MyInterceptor1 implements HandlerInterceptor {
    //没实现方法但没有报错，因为方法已被实现了，如果要改就重写

    /**
     * 预处理，controler方法执行前
     * return true放行，执行下一个拦截器，如果没有，执行controller中的方法
     * return false不放行
     * @param request
     * @param response
     * @param handler
     * @return
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("MyInterceptor1执行了。。。");
        return true;
    }
}

springMVC.xml中配置拦截器

    <!--配置拦截器-->
    <mvc:interceptors>
        <mvc:interceptor>
            <!--要拦截的具体方法-->
            <mvc:mapping path="/user/*"/>
            <!--不拦截的方法
            <mvc:exclude-mapping path=""/>-->
            <bean class="cn.itcast.interceptor.MyInterceptor1"></bean>
        </mvc:interceptor>
    </mvc:interceptors>

index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<h3>拦截器</h3>
<a href="user/testInterceptor">拦截器</a>
</body>
</html>

success.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<h3>执行成功</h3>
<%System.out.println("success.jsp执行了。。");%>
</body>
</html>

效果

拦截器接口方法

不放行的情况
跳转到错误页面

package cn.itcast.interceptor;

import org.springframework.web.servlet.HandlerInterceptor;

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

/**
 * 自定义拦截器
 * @author yuqiong
 * @date 2019/6/19-12:25
 */
public class MyInterceptor1 implements HandlerInterceptor {
    //没实现方法但没有报错，因为方法已被实现了，如果要改就重写

    /**
     * 预处理，controler方法执行前
     * return true放行，执行下一个拦截器，如果没有，执行controller中的方法
     * return false不放行
     * @param request
     * @param response
     * @param handler
     * @return
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("MyInterceptor1执行了。。。");
        request.getRequestDispatcher("/WEB-INF/pages/error.jsp").forward(request,response);
        return false;
    }
}

error.jsp页面

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<h3>错误页面</h3>
</body>
</html>

postHandle方法

    /**
     * 后处理方法，controller方法执行后，success.jsp执行之前
     * @param request
     * @param response
     * @param handler
     * @param modelAndView
     * @throws Exception
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("MyInterceptor1执行了。。。后");
    }

postHandle添加执行页面

    /**
     * 后处理方法，controller方法执行后，success.jsp执行之前
     * @param request
     * @param response
     * @param handler
     * @param modelAndView
     * @throws Exception
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("MyInterceptor1执行了。。。后");
        request.getRequestDispatcher("/WEB-INF/pages/error.jsp").forward(request,response);
    }
}

afterCompletion方法

    /**
     *success.jsp页面执行后，该方法会执行
     * @param request
     * @param response
     * @param handler
     * @param ex
     * @throws Exception
     */
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("MyInterceptor1执行了。。。最后");
    }

配置第二个拦截器

新建一个拦截器

package cn.itcast.interceptor;

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

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

/**
 * @author yuqiong
 * @date 2019/6/19-16:41
 */
public class MyInterceptor2 implements HandlerInterceptor {
    //没实现方法但没有报错，因为方法已被实现了，如果要改就重写

    /**
     * 预处理，controler方法执行前
     * return true放行，执行下一个拦截器，如果没有，执行controller中的方法
     * return false不放行
     * @param request
     * @param response
     * @param handler
     * @return
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("MyInterceptor1执行了。。。222");
        //request.getRequestDispatcher("/WEB-INF/pages/error.jsp").forward(request,response);
        return true;
    }

    /**
     * 后处理方法，controller方法执行后，success.jsp执行之前
     * @param request
     * @param response
     * @param handler
     * @param modelAndView
     * @throws Exception
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("MyInterceptor1执行了。。。后222");
        request.getRequestDispatcher("/WEB-INF/pages/error.jsp").forward(request,response);
    }

    /**
     *success.jsp页面执行后，该方法会执行
     * @param request
     * @param response
     * @param handler
     * @param ex
     * @throws Exception
     */
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("MyInterceptor1执行了。。。最后222");
    }
}

springmvc中配置拦截器2

    <!--配置拦截器-->
    <mvc:interceptors>
        <mvc:interceptor>
            <!--要拦截的具体方法-->
            <mvc:mapping path="/user/*"/>
            <!--不拦截的方法
            <mvc:exclude-mapping path=""/>-->
            <bean class="cn.itcast.interceptor.MyInterceptor1"></bean>
        </mvc:interceptor>

        <!--配置第二个拦截器-->
        <mvc:interceptor>
            <!--要拦截的具体方法-->
            <mvc:mapping path="/**"/>
            <!--不拦截的方法
            <mvc:exclude-mapping path=""/>-->
            <bean class="cn.itcast.interceptor.MyInterceptor2"></bean>
        </mvc:interceptor>
    </mvc:interceptors>

java web 笔记

springmvc（idea版第二天）

相应数据和结果视图

返回值分类

关键字转发和重定向

ResponseBody响应json数据

springMVC实现文件上传

springMVC上传

跨服务器上传

springMVC的异常处理

springMVC的拦截器

springmvc（idea版 第二天）

相应数据和结果视图

返回值分类

关键字转发和重定向

ResponseBody响应json数据

springMVC实现文件上传

springMVC上传

跨服务器上传

springMVC的异常处理

springMVC的拦截器

springmvc（idea版第二天）