beaninfo封装，实现javabean与map的双向转化

最新推荐文章于 2021-12-06 13:59:37 发布

原创最新推荐文章于 2021-12-06 13:59:37 发布 · 723 阅读

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本文介绍了一个用于Java Bean和Map相互转换的工具类实现。通过Java反射机制，该工具类能够轻松地将Java Bean实例转化为Map对象，或将Map对象转换为Java Bean实例。

我们知道，反射是Java的灵魂，笔者最近做一个javase的小项目时，需要用到java反射的知识，所以封装了一套小的工具类，目的是实现javabean到map的自由转化；

好了，废话不多说，我们直接上代码吧….

工具类代码：

package utils;

import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;

public class BeanInfoUtils <T>{

    /***
     * 由bean转化成map
     * @param t
     * @return
     */
    public Map<String, Object> beanTransformToMap(T t){
        Map<String, Object> result = new HashMap<String,Object>();
        PropertyDescriptor[] pds = getProperties(t);
            for(PropertyDescriptor pd : pds){
                String key = pd.getName();
                if(!key.equals("class")){
                    Method getter = pd.getReadMethod();
                    try {
                        Object value = getter.invoke(t);
                        result.put(key, value);
                    } catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
                        e.printStackTrace();
                    }
                }
            }
        return result;
    }

    /***
     * 由map转化成bean
     * @param map
     * @param t
     * @return
     */
    public T mapTransformToBean(Map<String, Object> map,T t){
        PropertyDescriptor[] pds = getProperties(t);
        for(PropertyDescriptor pd : pds){
            String key = pd.getName();
            if(map.containsKey(key)){
                Object value = map.get(key);
                Method setter = pd.getWriteMethod();
                try {
                    setter.invoke(t, value);
                } catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                    return null;
                }
            }
        }
        return t;
    }

    /***
     * 得到对象的属性数组
     * @param t
     * @return
     */
    public PropertyDescriptor[] getProperties(T t){
        BeanInfo bi = null;
        try {
            bi = Introspector.getBeanInfo(t.getClass());
        } catch (IntrospectionException e) {
            e.printStackTrace();
        }
        if(bi == null ) return null;
        else return bi.getPropertyDescriptors();
    }
}

bean代码：

package pojo;

import java.util.Date;

import utils.IDUtils;

/***
 * 用户
 * @author Elliot
 *
 */
public class User {
    private String id;//用户id  使用时间生成策略
    private String username;//用户名
    private String nickname;//昵称
    private String password;//密码
    private Double balance;//余额
    private String createTime;//用户创建时间

    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getNickname() {
        return nickname;
    }
    public void setNickname(String nickname) {
        this.nickname = nickname;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public Double getBalance() {
        return balance;
    }
    public void setBalance(Double balance) {
        this.balance = balance;
    }
    public String getCreateTime() {
        return createTime;
    }
    public void setCreateTime(String createTime) {
        this.createTime = createTime;
    }
    public User() {
        super();
    }
    public User(String username, String nickname, String password) {
        super();
        this.id = System.currentTimeMillis() + "";
        this.username = username;
        this.nickname = nickname;
        this.password = password;
        this.balance = 0.0;
        this.createTime = new Date().toString();
    }
    @Override
    public String toString() {
        return "User [id=" + id + ", username=" + username + ", nickname=" + nickname + ", password=" + password
                + ", balance=" + balance + ", createTime=" + createTime + "]";
    }

}

测试：

public static void main(String[] args) {

        User u = new User("LuciferMS", "Elliot", "123456");
        BeanInfoUtils<User> biu = new BeanInfoUtils<User>();
        Map<String, Object> map = biu.beanTransformToMap(u);
        for(Entry<String, Object> e : map.entrySet()){
            System.out.println(e.getKey() + " : " + e.getValue());
        }

        System.out.println("\n---------美丽的分割线------\n");
        u = biu.mapTransformToBean(map, new User());
        System.out.println(u);

    }