public class Test {

 static class ThreadOne extends Thread {

  private Callback mCallback;

  @Override
  public void run() {
   work();
   if (mCallback != null) {
    mCallback.onResult(false);
   }
  }

  // 耗时 3s
  private void work() {
   System.out.println(" 正在查询数据库 1");
   long startTime = System.currentTimeMillis();
   while (true) {
    if (System.currentTimeMillis() - startTime < 3000) {
     continue;
    }
    break;
   }
  }

  public void setCallback(Callback callback) {
   mCallback = callback;
  }

  public interface Callback {
   void onResult(boolean result);
  }
 }

 static class ThreadTest extends Thread {

  private Object mLock = new Object();

  private ThreadOne mThreadOne;

  @Override
  public void run() {
   workOne();
   System.out.println(" 根据结果继续做其他事情 ");
  }

  private void workOne() {
   mThreadOne = new ThreadOne();
   mThreadOne.setCallback(new ThreadOne.Callback() {
    @Override
    public void onResult(boolean result) {
     System.out.println(" 查询数据库 1 结束，:" + (result ? " 有数据 " : " 无数据 "));
     synchronized (mLock) {
      mLock.notify();
      System.out.println("--ThreadTest 结束等待 --");
     }
    }
   });
   mThreadOne.start();
   try {
    synchronized (mLock) {
     System.out.println("--ThreadTest 进入等待 --");
     mLock.wait();
    }
   } catch (InterruptedException e) {
    e.printStackTrace();
   }
  }
 }

 public static void main(String[] var0) {
  ThreadTest threadTest = new ThreadTest();
  threadTest.start();
 }
}

--ThreadTest 进入等待--
正在查询数据库 1
查询数据库 1 结束，: 无数据
--ThreadTest 结束等待--
根据结果继续做其他事情

public class Test {

 private static Object mLock = new Object();

 static class MyThread extends Thread {

  String mName;
  Callback mCallback;

  public MyThread(String name){
   mName = name;
  }

  @Override
  public void run() {
   work();
   if (mCallback != null) {
    mCallback.onResult(false);
   }
  }

  // 耗时 3s
  private void work() {
   System.out.println(mName + " 等待 ");
   try {
    synchronized (mLock) {
     mLock.wait();
    }
   } catch (InterruptedException e) {
    e.printStackTrace();
   }
  }

  public void setCallback(Callback callback) {
   mCallback = callback;
  }

  public interface Callback {
   void onResult(boolean result);
  }
 }

 static class ThreadTest extends Thread {



  @Override
  public void run() {
   work("db1");
   work("db2");
   work("db3");

   try {
    sleep(2000);
   } catch (InterruptedException e) {
    e.printStackTrace();
   }

   synchronized (mLock) {
    System.out.println(" 唤醒全部 ");
    mLock.notifyAll();
   }
  }

  private void work(String name) {
   final MyThread myThread = new MyThread(name);
   myThread.setCallback(new MyThread.Callback() {
    @Override
    public void onResult(boolean result) {
     System.out.println(myThread.mName + " 回来了 ");
    }
   });
   myThread.start();
  }
 }

 public static void main(String[] var0) {
  ThreadTest threadTest = new ThreadTest();
  threadTest.start();
 }
}