反射小练习

package com.example.demo;

import lombok.Data;
import org.apache.commons.lang3.StringUtils;
import org.junit.jupiter.api.Test;

import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Objects;

/**

• @author xiefenghong
• @date 2022年02月14日 14:50
• @describe 反射属性赋值

*/
public class ReflectTest {

@Test
public void run(){
    Person person = ClassInstanceFactory.createInstance(Person.class, "name:小明|id:1|cloth:{name:大衣|category:{name:羊毛衫}}|sex:male");
    System.out.println(person);
}

}
/*

• @Author xiefenghong
• @Description 实例工厂，用于实例化对象
• @Date 18:20 2022/2/14
• @Param
• @return

**/
class ClassInstanceFactory{

private  ClassInstanceFactory(){};
public static <T>T createInstance(Class<T> obj,String value){
    T instance =null;
    try {
        instance = obj.getDeclaredConstructor().newInstance();
        InstallBeanUtils.installBeanValue(instance,value);
    } catch (InstantiationException e) {
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        e.printStackTrace();
    } catch (NoSuchMethodException e) {
        e.printStackTrace();
    } catch (InvocationTargetException e) {
        e.printStackTrace();
    } catch (NoSuchFieldException e) {
        e.printStackTrace();
    }
    return instance;
}

}
@Data
class Person{

private String name;
private Integer id;
private Cloth cloth;
private String sex;

}
@Data
class Cloth{

private String name;
private Category category;

}
@Data
class Category{

private String name;

}
/**

• @Author xiefenghong
• @Description 封装属性工具类
• @Date 18:20 2022/2/14
• @Param
• @return

**/
class InstallBeanUtils{

/*
 * @Author xiefenghong
 * @Description 属性封装
 * @Date 18:20 2022/2/14
 * @Param [obj, val]
 * @return void
 **/
public static void installBeanValue(Object obj,String val) throws NoSuchFieldException, NoSuchMethodException, InvocationTargetException, IllegalAccessException {
    if (StringUtils.isBlank(val)){
        return;
    }
    if(Objects.isNull(obj)){
        throw new NullPointerException("实例对象为null");
    }
    String valParent=val;
    String valChild=null;
    if(val.contains("{")){
        valParent=val.substring(0,val.indexOf("{"))+"?"+val.substring(val.lastIndexOf("}")+1);
        valChild=val.substring(val.indexOf("{")+1,val.lastIndexOf("}"));
    }
    Class<?> aClass = obj.getClass();
    String[] valuePairs = valParent.split("\\|");
    for (String valuePair : valuePairs){
        try {
            String[] values = valuePair.split(":");
            Field field = aClass.getDeclaredField(values[0]);
            if(valuePair.contains("?")){
                Method method = aClass.getDeclaredMethod(methodNameJoint("get",field));
                Object childObj = method.invoke(obj);
                if (Objects.isNull(childObj)){
                    Method setMethod = aClass.getDeclaredMethod(methodNameJoint("set", field), field.getType());
                    setMethod.invoke(obj,field.getType().getConstructor().newInstance());
                    childObj= method.invoke(obj);
                }
                try {
                    installBeanValue(childObj,valChild);
                }catch (Exception e){
                    System.out.println("子类赋值失败");
                }
                continue;
            }
            Method method = aClass.getDeclaredMethod(methodNameJoint("set",field), field.getType());
            Object value= methodTypeValue(field, values[1]);
            method.invoke(obj,value);
        }catch (Exception e){
            System.out.println(valuePair+"赋值失败");
        }
    }
}
/**
 * @Author xiefenghong
 * @Description 属性的值类型转换
 * @Date 18:23 2022/2/14
 * @Param [field, val]
 * @return java.lang.Object
 **/
protected static Object methodTypeValue(Field field,String val){
    Object obj=null;
    if("java.lang.String".equals(field.getType().getName())){
        return val;
    }else if ("java.lang.Integer".equals(field.getType().getName())){
        obj=Integer.valueOf(val);
    }
    return obj;
}
/*
 * @Author xiefenghong
 * @Description 获取get，set方法
 * @Date 18:23 2022/2/14
 * @Param [prefix, field]
 * @return java.lang.String
 **/
protected static String methodNameJoint(String prefix,Field field){
    String name = field.getName().substring(0, 1).toUpperCase();
    if (field.getName().length()==1){
        return prefix+name;
    }
    return prefix+name+field.getName().substring(1);
}

}