IP查询系统的异步回调案例

package com.lxj.demo;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;
public class Http extends Thread{
  // 下载结束的回调接口
  public interface IResult{
    void success(String msg);
    void fail(String msg);
  }
  // 创建网络地址的引用
  String addr;
  // 创建回调接口的引用
  IResult iResult ;
  // 生成构造方法把网络和接口的引用传进去
  public Http(String addr, IResult iResult) {
    super();
    this.addr = addr;
    this.iResult = iResult;
    // 开启线程 线程一开启就产生了异步
    start();
  }
  @Override
  // 重写线程的run方法，只要是网络就要用到多线程
  public void run() {
    try {
      // 创建URL，把网络地址传进去
      URL url = new URL(addr);
      try {
        // 利用字符缓冲读取流读取网络数据
        BufferedReader br = new BufferedReader(new InputStreamReader(url.openStream()));
        // 创建stringbuffer对象
        StringBuffer sb = new StringBuffer();
        // 创建一个临时储存字符串的变量
        String temp;
        // 当temp不为空是就一直读取数据
        while ((temp = br.readLine()) != null) {
          sb.append(temp);
        }
        // 数据读取成功后
        // 把读取的所有数据传到回调接口，再由接口传出去
        iResult.success(sb.toString());
      } catch (IOException e) {
        e.printStackTrace();
      }
    } catch (MalformedURLException e) {
      e.printStackTrace();
      // 网络请求发生异常
      iResult.fail("网络请求失败");
    }
  }
}

package com.lxj.demo;
import net.sf.json.JSONObject;
import com.xykj.demo.Http.IResult;
public class IPRequest {
  // 请求IP信息的回调接口，在这里必须要使用回调，因为不知道Http什么时候下载完成
  public interface IRequest{
    void success(IPBean ipBean);
    void fail(String msg);
  }
  // 只要给一个ip地址和回调接口，我们可以通过回调接口传回转化好的ip信息对象
  public void request(String IP,IRequest iRequest){
    // 把用户输入的ip地址拼接到url中，发起Http请求
    String addr ="http://apicloud.mob.com/ip/query?key=520520test&ip="
        + IP
        + "";
    new Http(addr, new IResult() {
      // 创建完的IResult success和fail不会马上调用，必须要等到Http下载完成或者发生异常才会调用
      @Override
      public void success(String msg) {
        // 把接收的json数据转化成IPBean对象
        JSONObject jsonObject = JSONObject.fromObject(msg);
        IPBean ipBean = (IPBean) JSONObject.toBean(jsonObject, IPBean.class);
        // 产生回调，把转化好的对象传递出去给Demo
        iRequest.success(ipBean);
      }
      @Override
      public void fail(String msg) {
        // Http请求失败的时候
        iRequest.fail(msg);
      }
    });
  }
}

package com.lxj.demo;
public class IPBean {
  public static class Result{
    private String city;
    private String country;
    private String ip;
    private String province;
    public String getCity() {
      return city;
    }
    public void setCity(String city) {
      this.city = city;
    }
    public String getCountry() {
      return country;
    }
    public void setCountry(String country) {
      this.country = country;
    }
    public String getIp() {
      return ip;
    }
    public void setIp(String ip) {
      this.ip = ip;
    }
    public String getProvince() {
      return province;
    }
    public void setProvince(String province) {
      this.province = province;
    }
    @Override
    // 这里必须要重写toString方法，否则将打印的内存里面的地址
    public String toString() {
      return "city：" + city + "\ncountry：" + country + "\nip："
          + ip + "\nprovince：" + province;
    }
  }
  Result result;
  private String msg;
  private String retCode;
  public Result getResult() {
    return result;
  }
  public void setResult(Result result) {
    this.result = result;
  }
  public String getMsg() {
    return msg;
  }
  public void setMsg(String msg) {
    this.msg = msg;
  }
  public String getRetCode() {
    return retCode;
  }
  public void setRetCode(String retCode) {
    this.retCode = retCode;
  }
}

package com.lxj.demo;
import java.util.Scanner;
import com.xykj.demo.IPRequest.IRequest;
public class Demo {
  public static void main(String[] args) {
    System.out.println("************欢迎使用IP查询系统************");
    Scanner sc = new Scanner(System.in);
    // 创建IPRequest对象
    IPRequest ipRequest = new IPRequest();
    while (true) {
      System.out.println("请输入要查询的IP:");
      String ip = sc.next();
      // 调用IPRequest里面的request方法
      ipRequest.request(ip, new IRequest() {
        @Override
        public void success(IPBean ipBean) {
          System.out.println("*************查询结果*************");
          System.out.println(ipBean.getResult());
        }
        @Override
        public void fail(String msg) {
          System.out.println(msg);
        }
      });
    }
  }
}