Java如何获取接口所有的实现类

目录

• Java获取接口所有的实现类
• 反射获取接口的所有实现类
• 总结

Java获取接口所有的实现类

最近因业务需求，要实现NodeRed服务后端化，为使各个节点的解析进行插件化（NodeRed各个节点也是插件化，安装插件即可使用） ，后端不得不动态加载解析NodeRed节点json，用一个接口来统一管理。

import cn.hutool.core.util.ClassUtil;
import java.util.*;

/**
 * 此类用来解析NodeRed服务器的json串
 */
public class NodeRedParseUtil {

    public static void main(String[] args) throws IllegalAccessException, InstantiationException {
        //获取所有的模型实现类
        Set<Class<?>> classes = ClassUtil.scanPackageBySuper("com.ciih.nodred.plugins", NodeRedModel.class);
        Map<String, NodeRedModel> map = new HashMap<>(classes.size());
        for (Class<?> aClass : classes) {
            //实例化
            Object o = aClass.newInstance();
            System.out.println();
            if (o instanceof NodeRedModel) {
                NodeRedModel nodeRedModel = (NodeRedModel) o;
                map.put(nodeRedModel.getType(), nodeRedModel);
            }
        }
    }

}

反射获取接口的所有实现类

添加依赖

implementation 'org.reflections:reflections:0.9.12'

接口

package com.example.myapplication.people;

public interface IPeople {
  String say();
}

实现类

package com.example.myapplication.people;

public class Student implements IPeople{

  @Override
  public String say() {
    return "I am a student";
  }
}

package com.example.myapplication.people;

public class Teacher implements IPeople{

  @Override
  public String say() {
    return "I am a teacher";
  }
}

工具类

package com.example.myapplication;

import android.net.IpPrefix;
import com.example.myapplication.people.IPeople;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import org.reflections.Reflections;

public class Utils {
  public static Map<String,Class> getAllIPeopleImpl(){
    Reflections reflection=new Reflections("com.example.myapplication.people");
    Map<String,Class> map=new HashMap<>();
    Set<Class<? extends IPeople>> set=reflection.getSubTypesOf(IPeople.class);
    for(Class c:set){
      map.put(c.getSimpleName(),c);
    }
    return map;
  }
}

测试类

package com.example.myapplication;

import com.example.myapplication.people.IPeople;
import java.util.Map;
import org.junit.Test;

import static org.junit.Assert.*;

/**
 * Example local unit test, which will execute on the development machine (host).
 *
 * @see <a href="http://d.android.com/tools/testing" rel="external nofollow" >Testing documentation</a>
 */
public class ExampleUnitTest {
  
  @Test
  public void test() {
    Map<String, Class> map = Utils.getAllIPeopleImpl();
    try {
      for (String str : map.keySet()) {
        Object people = map.get(str).newInstance();
        if(people instanceof IPeople){
          System.out.println(str);
          System.out.println(((IPeople) people).say());
        }
      }
    } catch (IllegalAccessException | InstantiationException e) {
      e.printStackTrace();
    }
  }
}

总结

以上为个人经验，希望能给大家一个参考，也希望大家多多支持我们。