java反射在單元測試中的應用

java反射

反射的意義

• 單元測試private方法

代碼

實體類

package com.xin.test;

/**
 * Created by r.x on 2017/7/6.
 */
public class User {
    private String name;
    private int age;

    @Override
    public String toString() {
        return "User{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

待反射的類

package com.xin.test;

/**
 * Created by r.x on 2017/7/6.
 */
public class ReflectDemo {
    public void outer(User user, String job, int time) {
        System.out.println("公衆信息：" + user.getName() + "，" + user.getAge() + "歲。表面從事" + job + "工作長達" + time + "年");
    }

    public void inner(User user, String job, int time) {
        System.out.println("內部消息：" + user.getName() + "，" + user.getAge() + "歲。實際從事" + job + "工作長達" + time + "年");
    }
}

單元測試類

package com.xin.test;

import org.junit.Test;
import java.lang.reflect.Method;

/**
 * Created by r.x on 2017/7/6.
 */
public class ReflectDemoTest {
    @Test
    public void testOuter() throws Exception{
        Class<?> clazz = ReflectDemo.class;
        Object reflectDemo = clazz.newInstance();
        // 通過getMethod獲取public方法
        // **注意：int.class不能寫成Integer.class，否則會報NoSuchMethodException**
        Method outer = clazz.getMethod("outer", User.class, String.class, int.class);
        User user = new User() {
            {
                setName("老王");
                setAge(38);
            }
        };
        outer.invoke(reflectDemo, user, "程序猿", 5);
    }

    @Test
    public void testInner() throws Exception {
        Class<?> clazz = Class.forName("com.xin.test.ReflectDemo");
        Object reflectDemo = clazz.newInstance();
        // 通過getDeclaredMethod獲取
        Method inner = clazz.getDeclaredMethod("inner", User.class, String.class, int.class);
        // 必須設置爲true，否則會拋出NoSuchMethodException
        inner.setAccessible(true);
        User user = new User() {
            {
                setName("老王");
                setAge(38);
            }
        };
        inner.invoke(reflectDemo, user, "單身狗", 25);
    }
}

運行結果

內部消息：老王，38歲。實際從事單身狗工作長達25年
公衆信息：老王，38歲。表面從事程序猿工作長達5年