SpringMVC系列（四）使用 POJO 对象绑定请求参数值

在实际开发中如果参数太多就不能使用@RequestParam去一个一个的映射了，需要定义一个实体参数对象(POJO)来映射请求参数。Spring MVC 会按请求参数名和 POJO 属性名进行自动匹配，自动为该对象填充属性值。支持级联属性。如：address.province、address.city等。

具体步骤如下：

1.定义需要的请求参数的实体

User.java

 package com.study.springmvc.model;

 public class User {

     private String username;
     private String password;

     private String email;
     private int age;

     private Address address;

     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 String getEmail() {
         return email;
     }

     public void setEmail(String email) {
         this.email = email;
     }

     public int getAge() {
         return age;
     }

     public void setAge(int age) {
         this.age = age;
     }

     public Address getAddress() {
         return address;
     }

     public void setAddress(Address address) {
         this.address = address;
     }

     @Override
     public String toString() {
         return "User [username=" + username + ", password=" + password + ", email=" + email + ", age=" + age
                 + ", address=" + address + "]";
     }

 }

Address.java

 package com.study.springmvc.model;

 public class Address {

     private String province;
     private String city;

     public String getProvince() {
         return province;
     }

     public void setProvince(String province) {
         this.province = province;
     }

     public String getCity() {
         return city;
     }

     public void setCity(String city) {
         this.city = city;
     }

     @Override
     public String toString() {
         return "Address [province=" + province + ", city=" + city + "]";
     }

 }

2. 在index.jsp页面编写传参的表单

 <!--POJO测试 begin  -->
 <br>
 <form action="pojoTest/testPojo" method="post">
     username: <input type="text" name="username"/>
     <br>
     password: <input type="password" name="password"/>
     <br>
     email: <input type="text" name="email"/>
     <br>
     age: <input type="text" name="age"/>
     <br>
     city: <input type="text" name="address.city"/>
     <br>
     province: <input type="text" name="address.province"/>
     <br>
     <input type="submit" value="Submit"/>
 </form>
 <!--POJO测试 end  --> 

3.编写handler

PojoTest.java

 package com.study.springmvc.handlers;

 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.RequestMapping;

 import com.study.springmvc.model.User;

 @RequestMapping("/pojoTest")
 @Controller
 public class PojoTest {

     public static final String SUCCESS="success";

     /**
      * Spring MVC 会按请求参数名和 POJO 属性名进行自动匹配，
      * 自动为该对象填充属性值。支持级联属性。
      * 如：address.province、address.city等。
      */
     @RequestMapping("/testPojo")
     public String testPojo(User user) {
         System.out.println("testPojo: " + user);
         return SUCCESS;
     }
 }