Java通过反射获取Fields、Method、Constructor示例

1. getFields()和getDeclaredFields()

• getFields能获取该类和父类（包括Object）public的属性，getDeclaredFields获取该类public和private的属性

2. getMethods()和getDeclaredMethods()

• getMethods能获取该类和父类（包括Object）public的方法，getDeclaredMethods获取该类public和private的方法

3. getConstructors()和getDeclaredConstructors()

• getConstructors能获取该类public的构造方法，getDeclaredConstructors获取该类public和private的构造方法

示例代码：

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

public class TestReflection {
    public static void main(String[] args) throws ClassNotFoundException {
        Class c = Class.forName("Son");

        // 能获取该类和父类public的属性
        for (Field field : c.getFields()) {
            System.out.println(field);
        }
        System.out.println("====================");

        // 获取该类public和private的属性
        for (Field field : c.getDeclaredFields()) {
            System.out.println(field);
        }
        System.out.println("====================");

        // 能获取该类和父类public的方法
        for (Method method : c.getMethods()) {
            System.out.println(method);
        }
        System.out.println("====================");

        // 获取该类public和private的方法
        for (Method method : c.getDeclaredMethods()) {
            System.out.println(method);
        }
        System.out.println("====================");

        // 能获取该类public的构造方法
        for (Constructor constructor : c.getConstructors()) {
            System.out.println(constructor);
        }
        System.out.println("====================");

        // 获取该类public和private的构造方法
        for (Constructor declaredConstructor : c.getDeclaredConstructors()) {
            System.out.println(declaredConstructor);
        }
    }
}

class Son extends father {
    public String s1;

    private String s2;

    public String method1() {
        return "method1";
    }

    private String method2() {
        return "method2";
    }

    public Son() {
    }

    private Son(String test) {
    }
}

class father {
    public String s11;

    private String s22;

    public String method11() {
        return "method11";
    }

    private String method22() {
        return "method22";
    }

    public father() {
    }

    private father(String test) {
    }
}

结果：