SpringMVC07处理器方法的返回值详解编程语言

 <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 
     */ 
    [email protected](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 
     */ 
    [email protected](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 
     */ 
    [email protected](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; 
    } 
 
}

原创文章，作者：奋斗，如若转载，请注明出处：https://blog.ytso.com/12163.html

SpringMVC07处理器方法的返回值详解编程语言

相关推荐

发表回复