JavaSE 反射 Part2，javase反射part2

JavaSE 反射 Part2，javase反射part2

原作者： 尚硅谷-佟刚

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package com.atweihai.reflection;

import java.lang.reflect.Field;
import java.lang.reflect.Method;

import org.junit.Test;

public class ReflectionTest {

    @Test
    public void testClassField() throws Exception{
        String className="com.atweihai.reflection.Student";
        //可能为私有,可能在其父类中
        String fieldName="age";
        Object val=20;

        //创建className对应类的对象,并为其fieldName赋值为val
        Class clazz=Class.forName(className);
        Field field = getField(clazz, fieldName);

        Object obj=clazz.newInstance();
        setFieldValue(field, obj, val);

        Object fieldValue=getFieldValue(obj, field);
        System.out.println(fieldValue);

    }

    //获取指定字段的值
    private Object getFieldValue(Object obj,Field field) throws Exception{
        field.setAccessible(true);
        return field.get(obj);
    }

    //设置指定字段的值
    private void setFieldValue(Field field, Object obj, Object val) throws IllegalAccessException {
        field.setAccessible(true);;
        field.set(obj, val);
    }

    //获取指定字段
    private Field getField(Class clazz, String fieldName) {
        Field field=null;

        for(;clazz!=Object.class;clazz=clazz.getSuperclass()){
             try {
                field=clazz.getDeclaredField(fieldName);
                break;
            } catch (Exception e) {}    
        }
        return field;
    }


}