Spring MVC 参数绑定

客户端请求的参数到控制器功能处理方法上的参数的绑定，对于参数绑定非常灵活。

基本数据类型

package com.xxxx.springmvc.controller;

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

/**
 * 参数绑定
 */
@Controller
public class ParamsController {
    /**
     * 基本类型数据绑定
     * 参数值必须存在。如果没有指定参数值，也没有设置参数默认值，则会报500异常。
     * @param age
     * @param money
     */
    @RequestMapping("data01")
    public void data01(int age,double money){
        System.out.println(age);
        System.out.println(money);
    }


    /**
     * 基本类型数据绑定
     * 通过注解 @RequestParam 标记一个形参为请求参数。（注解声明在形参的前面）
     * 可以通过注解的属性设置相关内容
     *      设置参数的默认值 defaultValue
     * @param age
     * @param money
     */
    @RequestMapping("data02")
    public void data02(@RequestParam(defaultValue = "18") int age,
                       @RequestParam(defaultValue = "10.0") double money){
        System.out.println(age);
        System.out.println(money);
    }

    /**
     * 基本类型数据绑定
     * 通过注解 @RequestParam 标记一个形参为请求参数。（注解声明在形参的前面）
     * 可以通过注解的属性设置相关内容
     *      设置参数的参数名（别名） name
     * @param age
     * @param money
     */
    @RequestMapping("data03")
    public void data03(@RequestParam(defaultValue = "18",name = "userAge") int age,
                       @RequestParam(defaultValue = "10.0",name = "userMoney") double money){
        System.out.println(age);
        System.out.println(money);
    }

}

包装类型

    /**
     * 包装类型数据绑定 （如果数据是基本类型，建议使用包装类型）
     *      客户端请求参数名与方法形参名保持一致，默认参数值为null
     *      可以通过 @RequestParam 的name属性设置参数的别名，defaultValue属性设置参数默认值
     * @param age
     * @param money
     */
    @RequestMapping("data04")
    public void data05(Integer age,Double money){
        System.out.println(age);
        System.out.println(money);
    }

字符串类型

    /**
     * 字符串类型数据绑定
     *      客户端请求参数名与方法形参名保持一致，默认参数值为null
     *      可以通过 @RequestParam 的name属性设置参数的别名，defaultValue属性设置参数默认值
     * @param userName
     * @param userPwd
     */
    @RequestMapping("data05")
    public void data05(String userName,String userPwd){
        System.out.println(userName);
        System.out.println(userPwd);
    }

数组类型

    /**
     * 数组类型数据绑定
     * 客户端传参形式：ids=1&ids=2&ids=3
     * @param ids
     */
    @RequestMapping("data06")
    public void data06(String[] ids) {
        for (String id : ids) {
            System.out.println(id + "---");
        }
    }

JavaBean 类型

User对象

package com.xxxx.springmvc.vo;

public class User {
    private Integer userId;
    private String userName;
    private String userPwd;

    public Integer getUserId() {
        return userId;
    }

    public void setUserId(Integer userId) {
        this.userId = userId;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getUserPwd() {
        return userPwd;
    }

    public void setUserPwd(String userPwd) {
        this.userPwd = userPwd;
    }

    @Override
    public String toString() {
        return "User{" +
                "userId=" + userId +
                ", userName='" + userName + '\'' +
                ", userPwd='" + userPwd + '\'' +
                '}';
    }
}

package com.xxxx.springmvc.controller;

import com.xxxx.springmvc.vo.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

/**
 * 参数绑定
 */
@Controller
public class ParamsController {

    /**
     * JavaBean 数据绑定
     *      客户端请求的参数名与JavaBean对象的属性字段名保持一致
     * @param user
     */
    @RequestMapping("data07")
    public void data07(User user){
        System.out.println(user.toString());
    }

}

List 类型

此时 User 实体需要定义对应 list 属性。（对于集合的参数绑定，一般需要使用 JavaBean 对象进行包装）

phone实体

package com.xxxx.springmvc.vo;

public class Phone {

    private String num;

    public String getNum() {
        return num;
    }

    public void setNum(String num) {
        this.num = num;
    }

    @Override
    public String toString() {
        return "Phone{" +
                "num='" + num + '\'' +
                '}';
    }
}

User对象

package com.xxxx.springmvc.vo;

import java.util.ArrayList;
import java.util.List;

public class User {
    private Integer userId;
    private String userName;
    private String userPwd;

    private List<Phone> phones = new ArrayList<Phone>();

    public List<Phone> getPhones() {
        return phones;
    }

    public void setPhones(List<Phone> phones) {
        this.phones = phones;
    }

    public Integer getUserId() {
        return userId;
    }

    public void setUserId(Integer userId) {
        this.userId = userId;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getUserPwd() {
        return userPwd;
    }

    public void setUserPwd(String userPwd) {
        this.userPwd = userPwd;
    }

    @Override
    public String toString() {
        return "User{" +
                "userId=" + userId +
                ", userName='" + userName + '\'' +
                ", userPwd='" + userPwd + '\'' +
                ", phones=" + phones +
                '}';
    }
}

index.jsp页面定义

<%@page language="java" contentType="text/html; charset=UTF-8"%>
<html>
<head>
    <meta charset="UTF-8">
</head>
<body>
<h2>Hello World!</h2>
<form action="data08" method="get">
    <input name="phones[0].num" value="123"/>
    <input name="phones[1].num" value="456"/>
    <button type="submit">提交</button>
</form>
</body>
</html>

Controller 方法

    /**
     * 集合数据绑定
     *      一般情况，集合会通过JavaBean对象进行封装。传参是通过JavaBean中属性字段名设置集合的指定下标值即可。
     * @param user
     */
    @RequestMapping("data08")
    public void data08(User user){
        System.out.println(user.toString());
    }

Set类型

Set 和 List 类似，也需要绑定在对象上，而不能直接写在 Controller 方法的参数中。但是，绑定Set数据时，必须先在Set对象中add相应的数量的模型对象。

package com.xxxx.springmvc.vo;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

public class User {
    private int id;
    private String userName;
    private String userPwd;
    private Set<Phone> phones = new HashSet<Phone>();

    public User() {
        phones.add(new Phone());
        phones.add(new Phone());
        phones.add(new Phone());
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getUserPwd() {
        return userPwd;
    }

    public void setUserPwd(String userPwd) {
        this.userPwd = userPwd;
    }

    public Set<Phone> getPhones() {
        return phones;
    }

    public void setPhones(Set<Phone> phones) {
        this.phones = phones;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", userName='" + userName + '\'' +
                ", userPwd='" + userPwd + '\'' +
                ", phones=" + phones +
                '}';
    }
}

controller方法

    @RequestMapping("data09")
    public void data09(User user){
        System.out.println(user.toString());
    }

表单页面

<%@page language="java" contentType="text/html; charset=UTF-8"%>
<html>
<head>
    <meta charset="UTF-8">
</head>
<body>
<h2>Hello World!</h2>
<form action="data09" method="get">
    <input name="phones[0].num" value="123"/>
    <input name="phones[1].num" value="456"/>
    <input name="phones[2].num" value="789"/>
    <button type="submit">提交</button>
</form>
</body>
</html>

Map类型

package com.xxxx.springmvc.vo;

import java.util.*;

public class User {
    private int id;
    private String userName;
    private String userPwd;

    private Map<String,Phone> map = new HashMap<String,Phone>();

    public Map<String, Phone> getMap() {
        return map;
    }

    public void setMap(Map<String, Phone> map) {
        this.map = map;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getUserPwd() {
        return userPwd;
    }

    public void setUserPwd(String userPwd) {
        this.userPwd = userPwd;
    }


    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", userName='" + userName + '\'' +
                ", userPwd='" + userPwd + '\'' +
                ", map=" + map +
                '}';
    }
}

Controller方法

    @RequestMapping("data10")
    public void data10(User user) {
        Set<Map.Entry<String, Phone>> set = user.getMap().entrySet();
        for (Map.Entry<String, Phone> entry : set) {
            System.out.println(entry.getKey() + "--" + entry.getValue().getNum());
        }
    }

表单页面

<%@page language="java" contentType="text/html; charset=UTF-8"%>
<html>
<head>
    <meta charset="UTF-8">
</head>
<body>
<h2>Hello World!</h2>
<form action="data09" method="get">
    <input name="map[0].num" value="123"/>
    <input name="map[1].num" value="456"/>
    <input name="map[2].num" value="789"/>
    <button type="submit">提交</button>
</form>
</body>
</html>