Spring MVC的@ModelAttribute注解综合应用

本是古典何须时尚 2021-07-24 16:42 389阅读 0赞

**一 视图**

index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"  "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html;  charset=UTF-8">
    <title>测试@ModelAttribute</title>
    </head>
    <body>
    <h3>测试@ModelAttribute的不同用法</h3>
    <a href="loginForm1">测试@ModelAttribute(value="")注释返回具体类的方法 </a>
    
    <a href="loginForm2">测试@ModelAttribute注释void返回值的方法</a>
    
    <a href="loginForm3">测试@ModelAttribute注释返回具体类的方法</a>
    
    <a href="loginForm4">测试@ModelAttribute和@RequestMapping同时注释一个方法 </a>
    
    <a href="loginForm5">测试@ModelAttribute注释一个方法的参数  </a>
    
    </body>
    </html>

login4.jsp

loginForm1.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"  "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html;  charset=UTF-8">
    <title>测试@ModelAttribute</title>
    </head>
    <body>
    <h3>测试@ModelAttribute(value="")注释返回具体类的方法</h3>
    <form action="login1" method="post">
         <table>
             <tr>
                <td><label>登录名: </label></td>
                 <td><input type="text" id="loginname"  name="loginname" ></td>
             </tr>
             <tr>
                 <td><input id="submit" type="submit" value="登录"></td>
             </tr>
         </table>
    </form>
    </body>
    </html>

loginForm2.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"  "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html;  charset=UTF-8">
    <title>测试@ModelAttribute</title>
    </head>
    <body>
    <h3>测试@ModelAttribute注释void返回值的方法</h3>
    <form action="login2" method="post">
         <table>
             <tr>
                <td><label>登录名: </label></td>
                 <td><input type="text" id="loginname"  name="loginname" ></td>
             </tr>
             <tr>
                <td><label>密码: </label></td>
                 <td><input type="password" id="password"  name="password"></td>
             </tr>
             <tr>
                 <td><input id="submit" type="submit" value="登录"></td>
             </tr>
         </table>
    </form>
    </body>
    </html>

loginForm3.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"  "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html;  charset=UTF-8">
    <title>测试@ModelAttribute</title>
    </head>
    <body>
    <h3>测试@ModelAttribute注释返回具体类的方法</h3>
    <form action="login3" method="post">
         <table>
             <tr>
                <td><label>登录名: </label></td>
                 <td><input type="text" id="loginname"  name="loginname" ></td>
             </tr>
             <tr>
                <td><label>密码: </label></td>
                 <td><input type="password" id="password"  name="password"></td>
             </tr>
             <tr>
                 <td><input id="submit" type="submit" value="登录"></td>
             </tr>
         </table>
    </form>
    </body>
    </html>

loginForm4.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"  "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html;  charset=UTF-8">
    <title>测试@ModelAttribute</title>
    </head>
    <body>
    <h3>测试@ModelAttribute和@RequestMapping同时注释一个方法</h3>
    <form action="login4" method="post">
         <table>
             <tr>
                <td><label>登录名: </label></td>
                 <td><input type="text" id="loginname"  name="loginname" ></td>
             </tr>
             <tr>
                <td><label>密码: </label></td>
                 <td><input type="password" id="password"  name="password"></td>
             </tr>
             <tr>
                 <td><input id="submit" type="submit" value="登录"></td>
             </tr>
         </table>
    </form>
    </body>
    </html>

loginForm5.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"  "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html;  charset=UTF-8">
    <title>测试@ModelAttribute</title>
    </head>
    <body>
    <h3>测试@ModelAttribute注释一个方法的参数 </h3>
    <form action="login5" method="post">
         <table>
             <tr>
                <td><label>登录名: </label></td>
                 <td><input type="text" id="loginname"  name="loginname" ></td>
             </tr>
             <tr>
                <td><label>密码: </label></td>
                 <td><input type="password" id="password"  name="password"></td>
             </tr>
             <tr>
                 <td><input id="submit" type="submit" value="登录"></td>
             </tr>
         </table>
    </form>
    </body>
    </html>

result1.jsp

result2.jsp

result3.jsp

result5.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"  "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html;  charset=UTF-8">
    <title>测试@ModelAttribute注释一个方法的参数</title>
    </head>
    <body>
    访问request作用范围域中的user对象的loginname属性：${requestScope.user.loginname }
    访问request作用范围域中的user对象的password属性：${requestScope.user.password }
    访问request作用范围域中的user对象的username属性：${requestScope.user.username }
    
    </body>
    </html>

**二 控制器**

FormController.java

package org.fkit.controller;
    
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.PathVariable;
    import org.springframework.web.bind.annotation.RequestMapping;
    
    // Controller注解用于指示该类是一个控制器，可以同时处理多个请求动作
    @Controller
    public class FormController{
    
        // 该方法映射的请求为http://localhost:8080/ModelAttributeTest/{formName}
        @RequestMapping(value="/{formName}")
         public String loginForm(@PathVariable String formName){
            // 动态跳转页面
            return formName;
        }
    }

ModelAttribute1Controller.java

package org.fkit.controller;
    
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.ModelAttribute;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestParam;
    
    // Controller注解用于指示该类是一个控制器，可以同时处理多个请求动作
    @Controller
    public class ModelAttribute1Controller{
    
        // 使用@ModelAttribute注释的value属性，来指定model属性的名称,model属性对象就是方法的返回值
        @ModelAttribute("loginname")
        public String userModel1(
                @RequestParam("loginname") String loginname){
            return loginname;
        }
    
        @RequestMapping(value="/login1")
         public String login1() {
             return "result1";
         }
    
    }

ModelAttribute2Controller.java

package org.fkit.controller;
    
    import org.springframework.stereotype.Controller;
    import org.springframework.ui.Model;
    import org.springframework.web.bind.annotation.ModelAttribute;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestParam;
    
    // Controller注解用于指示该类是一个控制器，可以同时处理多个请求动作
    @Controller
    public class ModelAttribute2Controller{
    
        // model属性名称和model属性对象由model.addAttribute()实现，前提是要在方法中加入一个Model类型的参数。
        // 注意：当URL或者post中不包含对应的参数时，程序会抛出异常。
        @ModelAttribute
        public void userModel2(
                @RequestParam("loginname") String loginname,
                @RequestParam("password") String password,
                 Model model){
            model.addAttribute("loginname", loginname);
            model.addAttribute("password", password);
        }
    
        @RequestMapping(value="/login2")
         public String login2() {
             return "result2";
         }
    }

ModelAttribute3Controller.java

package org.fkit.controller;
    
    import java.util.ArrayList;
    import java.util.List;
    import org.fkit.domain.User;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.ModelAttribute;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestParam;
    
    
    // Controller注解用于指示该类是一个控制器，可以同时处理多个请求动作
    @Controller
    public class ModelAttribute3Controller{
        
        // 静态List<User>集合，此处代替数据库用来保存注册的用户信息
        private static List<User> userList;
        
        // UserController类的构造器，初始化List<User>集合
        public ModelAttribute3Controller() {
            super();
            userList = new ArrayList<User>();
            User user1 = new User("test","123456","测试用户");
            User user2 = new User("admin","123456","管理员");
            // 存储User用户，用于模拟数据库数据
            userList.add(user1);
            userList.add(user2);
        }
        
        // 根据登录名和密码查询用户，用户存在返回包含用户信息的User对象，不存在返回null
        public User find(String loginname,String password){
            for(User user: userList){
                if(user.getLoginname().equals(loginname) && user.getPassword().equals(password)){
                    return user;
                }
            }
            return null;
        }
    
        // model属性的名称没有指定，它由返回类型隐含表示，如这个方法返回User类型，那么这个model属性的名称是user。
        // 这个例子中model属性名称由返回对象类型隐含表示，model属性对象就是方法的返回值。它不需要指定特定的参数。
        @ModelAttribute
        public User userModel3(
                @RequestParam("loginname") String loginname,
                @RequestParam("password") String password){
            return find(loginname, password);
        }
    
        @RequestMapping(value="/login3")
         public String login3() {
             return "result3";
         }
    }

ModelAttribute4Controller.java

package org.fkit.controller;
    
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.ModelAttribute;
    import org.springframework.web.bind.annotation.RequestMapping;
    
    
    // Controller注解用于指示该类是一个控制器，可以同时处理多个请求动作
    @Controller
    public class ModelAttribute4Controller{
        
         // 这时这个方法的返回值并不是表示一个视图名称，而是model属性的值，视图名称是@RequestMapping的value值。
         // Model属性名称由@ModelAttribute(value=””)指定，相当于在request中封装了username（key）=admin（value）。
        @RequestMapping(value="/login4")
        @ModelAttribute(value="username")
         public String login4() {
             return "admin";
         }
    
    }

ModelAttribute5Controller.java

package org.fkit.controller;
    
    import org.fkit.domain.User;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.ModelAttribute;
    import org.springframework.web.bind.annotation.RequestMapping;
    
    // Controller注解用于指示该类是一个控制器，可以同时处理多个请求动作
    @Controller
    public class ModelAttribute5Controller{
    
            /*
             *  @ModelAttribute注释方法参数，会自动入参
             *  loginname控件的值会自动入参到User的loginname属性
             *  password控件的值会自动入参到User的password属性
             */
            @RequestMapping(value="/login5")
             public String login5(@ModelAttribute User user) {
                user.setUsername("管理员");
                 return "result5";
             }
    }

**三 领域模型**

package org.fkit.domain;
    import java.io.Serializable;
    
    // 域对象，实现序列化接口
    public class User implements Serializable{
         
         private static final long serialVersionUID = 1L;
         // 私有字段
         private String loginname;
         private String password;
         private String username;
         
         // 公共构造器
         public User() {
               super();
         }
         
         public User(String loginname, String password, String  username) {
               super();
               this.loginname = loginname;
               this.password = password;
               this.username = username;
         }
         // set/get方法
         public String getLoginname() {
               return loginname;
         }
         public void setLoginname(String loginname) {
               this.loginname = loginname;
         }
         public String getPassword() {
               return password;
         }
         public void setPassword(String password) {
               this.password = password;
         }
         public String getUsername() {
               return username;
         }
         public void setUsername(String username) {
               this.username = username;
         }
    }

**四 配置文件**

<?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:p="http://www.springframework.org/schema/p"
        xmlns:mvc="http://www.springframework.org/schema/mvc"
         xmlns:context="http://www.springframework.org/schema/context"
        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">
            
        
        <context:component-scan base-package="org.fkit.controller"/>
        
        <mvc:annotation-driven/>
         
        <mvc:default-servlet-handler/>
        
        
         <bean id="viewResolver"
               class="org.springframework.web.servlet.view.InternalResourceViewResolver"
              p:prefix="/WEB-INF/content/" p:suffix=".jsp"/>
        
    </beans>

**五 测试**

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第1个链接

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第2个链接

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第3个链接

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第4个链接

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第5个链接

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