SpringMVC(十七-二十) ModelAttribute 注解

有点难理解。

修饰方法是表示在该控制器的所有目标方法执行前都执行该modelattribute注解的方法。

修饰参数是表示什么？修饰参数时@modelattributes(value="xxxx") User user  中的value值需要和@modelattribute修改的方法加入的键的值一致。

Controller Code:

package com.tiekui.springmvc.handlers;

import java.util.Map;

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;

import com.tiekui.springmvc.pojo.Address;
import com.tiekui.springmvc.pojo.User;
import com.tiekui.springmvc.pojo.UserNew;

@Controller
public class ModelAttributes {

    @RequestMapping("testModelAttribute")
    public String targetMethod(UserNew user){
        System.out.println("Target method" + user);
        return "afterModelAttributes";
    }

    @ModelAttribute
    public void getuser(@RequestParam(value="id") String id,Map<String, UserNew> map) {

        if ((id != null)) {
            UserNew user = new UserNew("tiekui","1234","zhoutiekui@huawei.com",30,1, new Address("guangzhou", "zhenzhen"));
            System.out.println("Get an object" + user);
            map.put("userNew", user);
        }
    }
}

Response View:

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!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=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>

    userAge: ${requestScope.userNew.age}

</body>
</html>

View:

    <form action="testModelAttribute">
        <br>
        password : <input type="text" name="username" value="tiekui">
        <br>
        password : <input type="password" name="password" value="1234">
        <br>
        email : <input type="text" name="email" value="zhoutiekui@huawei.com">
        <br>
        age : <input type="text" name="age" value="18">
        <br>
        <input type="hidden" name="id" value="1">
        <br>
        Address Province: <input type="text" name="address.province" value="guangzhou">
        <br>
        Address City: <input type="text" name="address.city" value="shenzhen">
        <br>
        <input type="submit" value="Test ModelAttributes">
    </form>

POJO userNew:

 

POJO Address:

package com.tiekui.springmvc.pojo;

public class Address {
    private String province;
    private String city;

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