Java - 反射使用（调用私有方法、修改私有属性、获取父类私有字段）获取父类私有字段

调用私有方法

public class PrivateMethod {

    private String sayHello(String name) {
        return "hello "+name;
    }
}

测试

package com.java.test;
 
import java.lang.reflect.Method;
 
public class PrivateMethodTest {
 
    public static void main(String[] args)throws Exception {
        PrivateMethod  p = new PrivateMethod();
         
        Class<?> classType = p.getClass();
         
        Method method = classType.getDeclaredMethod("sayHello", new Class[]{String.class});
         
        method.setAccessible(true);//压制java的检查机制
         
        String str = (String)method.invoke(p, new Object[]{"lzyer"});
         
        System.out.println(str);
    }
}

修改私有属性

public class PrivateField{
 
    private String name="zhangsan";
     
    public String getName() {   
        return this.name;
    }
}

测试

package com.java.test;
 
import java.lang.reflect.Field;
 
public class PrivateFieldTest {
 
    public static void main(String[] args)throws Exception {
        PrivateField p = new PrivateField();
         
        Class<?> clazz = p.getClass();
         
        Field field = clazz.getDeclaredField("name");
         
        field.setAccessible(true);//压制java检查机制
         
        field.set(p, "lisi");
         
        System.out.println(p.getName());
    }
}

获取父类私有字段

@Test
public void myTest() {
    CustomerApiInfoReqDtoNew t = new CustomerApiInfoReqDtoNew();//改成你要操作的子类
    Class className = t.getClass();
    Map<String, Object> param = new HashMap<>();
    try{
        for (; className != Object.class; className = className.getSuperclass()) {//获取本身和父级对象
            Field[] fields = className.getDeclaredFields();//获取所有私有字段
            for (Field field : fields) {
                field.setAccessible(true);
                param.put(field.getName(), field.get(t) == null ? "" : field.get(t));
            }
        }
        System.out.print(JsonUtil.toJson(param));//打印子类和父类所有字段，注意：JsonUtil改成你自己的json解析工具
    }catch (Exception e){
        e.printStackTrace();
    }
}