java--模拟BeanUtils.populate()功能

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                    模拟Java内省的功能

准备工作
定义一个Model类，里面所有的属性都是private的，然后为每个属性提供getter和setter方法；
再准备一个Map，map的key值都是类里面的属性字段的字符串表示，值任意。
真正的工作
设计一个方法Object getModel(Map map,Class cls)，传入一个包含所有值的Map，然后再传入Model类的class，那么返回Model类的实例，这个实例里面已经包含好了所有相关的数据。也就是把Map中的数据通过反射，设置回到Model类实例中。

public class UserModel {    private String uuid,name,pwd;//用户编号，用户名称，用户密码    private int age;//用户类型    public UserModel() {    }    public String getUuid() {        return uuid;    }    public void setUuid(String uuid) {        this.uuid = uuid;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public String getPwd() {        return pwd;    }    public void setPwd(String pwd) {        this.pwd = pwd;    }    public int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }    @Override    public int hashCode() {        final int prime = 31;        int result = 1;        result = prime * result + ((uuid == null) ? 0 : uuid.hashCode());        return result;    }    @Override    public boolean equals(Object obj) {        if (this == obj)            return true;        if (obj == null)            return false;        if (getClass() != obj.getClass())            return false;        UserModel other = (UserModel) obj;        if (uuid == null) {            if (other.uuid != null)                return false;        } else if (!uuid.equals(other.uuid))            return false;        return true;    }    @Override    public String toString() {        return uuid + "," + name +",age=" + age+","+pwd;    }}

public class BookModel{    private String uuid,name;    private double inPrice,salePrice;    public BookModel(){    }    public String getUuid() {        return uuid;    }    public void setUuid(String uuid) {        this.uuid = uuid;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public double getInPrice() {        return inPrice;    }    public void setInPrice(double inPrice) {        this.inPrice = inPrice;    }    public double getSalePrice() {        return salePrice;    }    public void setSalePrice(double salePrice) {        this.salePrice = salePrice;    }    @Override    public int hashCode() {        final int prime = 31;        int result = 1;        long temp;        temp = Double.doubleToLongBits(inPrice);        result = prime * result + (int) (temp ^ (temp >>> 32));        return result;    }    @Override    public boolean equals(Object obj) {        if (this == obj)            return true;        if (obj == null)            return false;        if (getClass() != obj.getClass())            return false;        BookModel other = (BookModel) obj;        if (Double.doubleToLongBits(inPrice) != Double                .doubleToLongBits(other.inPrice))            return false;        return true;    }    @Override    public String toString() {        return uuid + ",《" + name + "》,进价："+ inPrice + ",售价：" + salePrice;    }}

import java.lang.reflect.Field;import java.lang.reflect.Method;import java.util.Map;public class myBeanUtils {    public static<T> T populate(Class<T> cls, Map<String, Object> map) throws Exception {        Object obj=cls.newInstance();        Field flds[]=cls.getDeclaredFields();        Object v=null;        for(Field fld:flds){             v=map.get(fld.getName());            if(v==null){                System.out.println(fld.getName()+"值为空...");                continue;            }            String methodName="set"+fld.getName().substring(0, 1).toUpperCase()+fld.getName().substring(1);            Method m=cls.getMethod(methodName, fld.getType());            m.invoke(obj, v);        }        return (T) obj;    }}

import java.util.HashMap;import java.util.Map;public class client {    public static void main(String[] args) {        Map<String, Object> map=new HashMap<String, Object>();        map.put("name", "Jack");        map.put("uuid", "001");        map.put("age", 12);//      map.put("pwd", "1234");        try {            UserModel um = myBeanUtils.populate(UserModel.class,map);//um:001,Jack,age=12,null            System.out.println("um:"+um);            System.out.println("------------------------");            BookModel bm = myBeanUtils.populate(BookModel.class,map);//bm:001,《Jack》,进价：0.0,售价：0.0            System.out.println("bm:"+bm);        } catch (Exception e) {            e.printStackTrace();        }    }}

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