• SpringMVC07处理器方法的返回值


     <body>
      <!--返回值是string的内部视图  -->
       <a href="student/add">add</a>
       
      <!--返回值是string的外部视图  -->
       <a href="student/taobao">淘宝</a>
       
      <!--没有返回值  转发到内部视图  -->
       <a href="student/request">request</a>
      <!--没有返回值  重定向到内部视图  -->
       <a href="student/response">response</a>
      </body>
    <?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
        xmlns:context="http://www.springframework.org/schema/context"
        xmlns:aop="http://www.springframework.org/schema/aop" 
        xmlns:tx="http://www.springframework.org/schema/tx"
        xsi:schemaLocation="
            http://www.springframework.org/schema/beans 
            http://www.springframework.org/schema/beans/spring-beans.xsd
            http://www.springframework.org/schema/context 
            http://www.springframework.org/schema/context/spring-context.xsd
            http://www.springframework.org/schema/tx 
            http://www.springframework.org/schema/tx/spring-tx.xsd
            http://www.springframework.org/schema/aop 
            http://www.springframework.org/schema/aop/spring-aop.xsd">
      <!-- 配置springmvc的组件  -->
      <context:component-scan base-package="cn.bdqn.controller"/>
      
      
      <!--  视图解析器      后台返回的是  success!  应该拿到的是  /WEB-INF/jsp/success.jsp 
      <bean  class="org.springframework.web.servlet.view.InternalResourceViewResolver">
         <property name="prefix" value="/WEB-INF/jsp/"/>
         <property name="suffix" value=".jsp"/>
      </bean> 
      -->
      
      <!--  配置外部视图解析器   就不需要  视图解析器了! -->
      <bean  class="org.springframework.web.servlet.view.BeanNameViewResolver"/>
      
      <!-- 外部视图 -->
      <bean id="taobao" class="org.springframework.web.servlet.view.RedirectView">
        <property name="url" value="http://www.taobao.com"/>
      </bean>
    </beans>
    @Controller
    @RequestMapping("/student")
    public class StudentController {
        
        /**
         * 返回值是string的内部视图  
         */
        @RequestMapping("/add")
        public  String  add(){
            System.out.println("进入了add");
            return  "success";
        }
        
        /**
         * 返回值是string的外部视图 
         */
        @RequestMapping("/taobao")
        public  String  taobao(){
            System.out.println("进入了taobao");
            return  "taobao";
        }
        /**
         * 没有返回值  转发到内部视图
         */
        @RequestMapping("/request")
        public  void  request(HttpServletRequest request,HttpServletResponse response){
            System.out.println("进入了request");
            //转发
            try {
                request.getRequestDispatcher("/WEB-INF/jsp/success.jsp").forward(request, response);
            } catch (ServletException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        /**
         * 没有返回值  重定向到内部视图
         */
        @RequestMapping("/response")
        public  void  response(HttpServletRequest request,HttpServletResponse response){
            System.out.println("进入了response");
            //重定向
            try {
                /**
                 * 重定向是  客户端的  行为!
                 * 能直接访问 web-inf ???  不行!
                 * response.sendRedirect("WEB-INF/jsp/success.jsp");
                 * 重定向到另一个方法 然后 那个方法做跳转!
                 * 
                 */
                response.sendRedirect("success.jsp");  //前提是根目录下有 success.jsp
                
                /**
                 * 这时候的路径http://localhost:8080/springmvc08/student/success.jsp
                 * 为什么会有student/这一层目录
                 * 原因:
                 *    用户点击的是 student/response
                 *    系统会默认拿到student/ 当成目前的路径!
                 *    再做重定向的时候会默认加上student/
                 */
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
      <body>
      <!-- 在controller中  实现 方法之间的跳转  -->
         <form action="student/changeMethod"  method="post">
         学生姓名:<input type="text" name="name"/>
        年龄:  <input type="password" name="age"/>
          <input type="submit" value="新增"/>
       </form> 
      </body>
    <?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
        xmlns:context="http://www.springframework.org/schema/context"
        xmlns:aop="http://www.springframework.org/schema/aop" 
        xmlns:tx="http://www.springframework.org/schema/tx"
        xsi:schemaLocation="
            http://www.springframework.org/schema/beans 
            http://www.springframework.org/schema/beans/spring-beans.xsd
            http://www.springframework.org/schema/context 
            http://www.springframework.org/schema/context/spring-context.xsd
            http://www.springframework.org/schema/tx 
            http://www.springframework.org/schema/tx/spring-tx.xsd
            http://www.springframework.org/schema/aop 
            http://www.springframework.org/schema/aop/spring-aop.xsd">
      <!-- 配置springmvc的组件  -->
      <context:component-scan base-package="cn.bdqn.controller"/>
      
      
      <!--  视图解析器      后台返回的是  success!  应该拿到的是  /WEB-INF/jsp/success.jsp -->
      <bean  class="org.springframework.web.servlet.view.InternalResourceViewResolver">
         <property name="prefix" value="/WEB-INF/jsp/"/>
         <property name="suffix" value=".jsp"/>
      </bean> 
      
      
    </beans>
    @Controller
    @RequestMapping("/student")
    public class StudentController {
        
        /**
         * 转发是默认的格式
         * 01.看路径
         * 02.看数据是否传递
         */
        @RequestMapping("/addRequest")
        public  ModelAndView  addRequest(Student student){
            System.out.println("进入了addRequest");
           ModelAndView  mv=new ModelAndView();
            mv.addObject("student", student).setViewName("success");
            return  mv;
        }
        
        /**
         * 重定向
         * 01.客户端行为 不能访问WEB-INF
         * 02.以访问的路径为准,所以上个例子中的student/  会出现!
         * 03.如果使用重定向 不加/  就是以上次访问的路径为准
         *    如果加上了/    就是以项目的跟路径为准
         */
        @RequestMapping("/addResponse")
        public  ModelAndView  addResponse(Student student){
            System.out.println("进入了addResponse");
            ModelAndView  mv=new ModelAndView();
            //需要在 webroot下 创建  success.jsp
            mv.addObject("student", student).setViewName("redirect:/success.jsp");
            return  mv;
        }
        /**
         * 跳转到内部方法
         */
        @RequestMapping("/changeMethod")
        public  String  changeMethod(Student student){
            System.out.println("进入了changeMethod");
            ModelAndView  mv=new ModelAndView();
            mv.addObject("student", student);
            //return  "redirect:list";   重定向 不能使用  /  跳转到当前controller中的list方法 ! 数据丢失
            return  "forward:list";//  转发list方法   数据肯定保留
        }
        
        @RequestMapping("/list")
        public  String  list(Student student){
            System.out.println("进入了list");  
            System.out.println(student.getName());
            System.out.println(student.getAge());
            return  "success";
        }
        
    }

    ==================接收并返回json数据======================

    需要导入jquery和 Gson的jar包

    <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
    <%
    String path = request.getContextPath();
    String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
    %>
    
    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    <html>
      <head>
        <base href="<%=basePath%>">
        
        <title>My JSP 'index.jsp' starting page</title>
        <meta http-equiv="pragma" content="no-cache">
        <meta http-equiv="cache-control" content="no-cache">
        <meta http-equiv="expires" content="0">    
        <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
        <meta http-equiv="description" content="This is my page">
        <!--
        <link rel="stylesheet" type="text/css" href="styles.css">
        -->
        
        
      <script type="text/javascript" src="js/jquery-1.8.3.js"></script>
        <script type="text/javascript">
          $(function(){
           $("button").click(function(){ //按钮的点击事件
               $.ajax({
                    url:"user/doAjax",
                    data:{
                     name:"小黑",
                     age:50
                    },
                    success:function(data){
                    /*  01.在前台转换成json数据
                    var json=eval("("+data+")");
                    alert(json.name+ "       "+json.age);  */
                    /*
                    02.在后台设置response.setContentType("application/json");
                      */
                    alert(data.name+ "       "+data.age); 
                    }
               })
           })
          
          })
         
        
        </script>
      </head>
      <body>
      <button>提交ajax请求</button>
      </body>
    </html>
    index.jsp页面
    <?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-3.0.xsd
            http://www.springframework.org/schema/mvc
            http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
            http://www.springframework.org/schema/context
            http://www.springframework.org/schema/context/spring-context-3.0.xsd">
    
    
    <!-- 配置需要扫描的包 -->
    <context:component-scan base-package="cn.bdqn.controller"/>
    <!-- 允许静态资源的访问  -->
    <mvc:resources location="/js/" mapping="/js/**"/>
    <!-- 开启注解 -->
    <mvc:annotation-driven/>
    <!-- 
    之前的
    <bean class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping"></bean>
    <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter"></bean>
     -->
    </beans>
    springmvc-servlet.xml文件
    @Controller
    @RequestMapping("/user")
    public class MyController {
    
        @RequestMapping("doAjax")
        public void doAjax(String name, int age, HttpServletResponse response)
                throws IOException {
            System.out.println("进入了doAjax......");
            System.out.println(name);
            System.out.println(age);
            // 放入map集合
            Map<String, Object> map = new HashMap<String, Object>();
            map.put("name", name);
            map.put("age", age);
    
            // response.setHeader("Content-type", "text/html;charset=utf-8");
            response.setContentType("application/json"); // 设置返回的是json页面
            Gson gson = new Gson();
            String json = gson.toJson(map);
            System.out.println("json=====" + json);
            // 把json数据返回给界面
            PrintWriter writer = response.getWriter();
            writer.print(json);
        }
    }
    Controller中的代码

    =================ajax验证用户名是否存在====================

    <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
    <%
    String path = request.getContextPath();
    String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
    %>
    
    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    <html>
      <head>
        <base href="<%=basePath%>">
        
        <title>My JSP 'success.jsp' starting page</title>
        
        <meta http-equiv="pragma" content="no-cache">
        <meta http-equiv="cache-control" content="no-cache">
        <meta http-equiv="expires" content="0">    
        <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
        <meta http-equiv="description" content="This is my page">
        <!--
        <link rel="stylesheet" type="text/css" href="styles.css">
        -->
    <script type="text/javascript" src="js/jquery-1.8.3.js"></script>
        <script type="text/javascript">
          $(function(){
          //验证用户名是否存在
           $("#userName").blur(function(){ //按钮的点击事件
           var name= $("#userName").val();
               $.ajax({
                    url:"user/addUser",
                    type:"post",
                    data:"userName="+name,
                    success:function(data){
                        alert(data);
                    }
               })
           })
          
          })
         
        
        </script>
      </head>
      
      <body>
      <h1>json验证</h1>
      
      用户名:<input type="text" id="userName" name="userName">
      </body>
    </html>
    创建一个对应的login.jsp
    /**
         * 用户名验证 ajax
         */
        @RequestMapping("/addUser")
        public void doAjax(String name, HttpServletResponse response)
                throws IOException {
            System.out.println("进入了addUser......");
            System.out.println(name);
            boolean flag = false;
            if (name.equals("admin")) {
                flag = true;
            }
            response.setContentType("application/json"); // 设置返回的是json页面
            Gson gson = new Gson();
            String json = gson.toJson(flag);
            System.out.println("json=====" + json);
            // 把json数据返回给界面
            PrintWriter writer = response.getWriter();
            writer.write(json);
        }
    在Controller中增加代码

    ==================处理器返回Object对象=====================

    导入需要的Jackson   jar包 

    <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
    <%
    String path = request.getContextPath();
    String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
    %>
    
    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    <html>
      <head>
        <base href="<%=basePath%>">
        
        <title>My JSP 'index.jsp' starting page</title>
        <meta http-equiv="pragma" content="no-cache">
        <meta http-equiv="cache-control" content="no-cache">
        <meta http-equiv="expires" content="0">    
        <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
        <meta http-equiv="description" content="This is my page">
        <!--
        <link rel="stylesheet" type="text/css" href="styles.css">
        -->
        
        
      <script type="text/javascript" src="js/jquery-1.8.3.js"></script>
        <script type="text/javascript">
          $(function(){
           $("button").click(function(){ //按钮的点击事件
               $.ajax({
                    url:"user/doAjax",
                    success:function(data){
                    // alert(data) 返回单个数据 使用
                    // alert(data.name+"   "+data.age);返回一个对象使用
                    //alert(data.user1.name+"   "+data.user2.name);  返回一个map集合
                    
                    $(data).each(function(i){
                       alert(data[i].name+"  "+data[i].age);  //返回一个list集合
                    })
                    }
               })
           })
          
          })
         
        
        </script>
      </head>
      <body>
      <button>提交ajax请求</button>
      </body>
    </html>
    index.jsp页面
    package cn.bdqn.controller;
    
    import java.util.ArrayList;
    import java.util.List;
    
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.ResponseBody;
    
    import cn.bdqn.bean.User;
    
    @Controller
    @RequestMapping("/user")
    public class MyController {
    
        /**
         * 01.返回的是一个Object对象
         * @return
         */
        /**    @RequestMapping("/doAjax")
            @ResponseBody
            // 把我们的返回的数据 放在相应体中
            public Object doAjax() {
                System.out.println("进入了doAjax......");
                return 45454.2515;
            }*/
    
        /**
         * 02.返回的是一个Object对象
         * produces :响应的界面格式
         */
        /**@RequestMapping(value = "/doAjax", produces = "text/html;charset=utf-8")
        @ResponseBody
        // 把我们的返回的数据 放在相应体中
        public Object doAjax() {
            System.out.println("进入了doAjax......");
            return "大家辛苦了";
        }*/
    
        /**
         * 03.返回的是一个Object对象
         */
        /**@RequestMapping(value = "/doAjax")
        @ResponseBody
        // 把我们的返回的数据 放在相应体中
        public Object doAjax() {
            System.out.println("进入了doAjax......");
            return new User("小黑", 50);
        }*/
        /**
         * 04.返回的是一个Map集合
         */
        /**@RequestMapping(value = "/doAjax")
        @ResponseBody
        // 把我们的返回的数据 放在相应体中
        public Object doAjax() {
            System.out.println("进入了doAjax......");
            Map<String, Object> map = new HashMap<String, Object>();
            map.put("user1", new User("小黑1", 50));
            map.put("user2", new User("小黑2", 50));
            return map;
        }*/
    
        /**
         * 05.返回的是一个list集合
         */
        @RequestMapping(value = "/doAjax")
        @ResponseBody
        // 把我们的返回的数据 放在相应体中
        public Object doAjax() {
            System.out.println("进入了doAjax......");
            List<User> list = new ArrayList<User>();
            list.add(new User("小黑1", 50));
            list.add(new User("小黑2", 60));
            return list;
        }
    
    }
    Controller代码
  • 相关阅读:
    jQuery height()、innerHeight()、outerHeight()函数的区别
    [css][移动设备]禁止横竖屏时内容自动调整
    document模板
    CSS3的appearance属性--改变元素的外观
    jQuery API中文文档
    jquery 获取元素的 实际宽度和高度
    为什么使用"use strict"可以节约你的时间
    ueditor的过滤、转义、格式丢失问题
    flask mysql
    WPF进阶之接口(2):IDisposable,ICollectionView
  • 原文地址:https://www.cnblogs.com/999-/p/6139877.html
Copyright © 2020-2023  润新知