HttpURLConnection的使用

使用thread,handler来联网读取json串

package com.bwoie.test;

import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;

import com.bwoie.test.adapter.GroupAdapter;
import com.bwoie.test.bean.GroupBean;
import com.bwoie.test.bean.GroupData;
import com.google.gson.Gson;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.view.Window;
import android.widget.ListView;

public class MainActivity extends Activity {

    private ListView lv;
    private ArrayList<GroupData> list;
    @SuppressLint("HandlerLeak")
    Handler handler=new Handler(){
        public void handleMessage(android.os.Message msg) {
            GroupAdapter adapter=new GroupAdapter(list, getApplicationContext());
            lv.setAdapter(adapter);
        };
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_main);

        lv = (ListView) findViewById(R.id.lv_q);
        init("http://121.42.8.95:8090/AndroidServer/gp.json");
    }

    private void init(final String uri) {
        new Thread(){
            public void run() {
                try {
                    //创建URL对象
                    URL url=new URL(uri);
                    //通过URL打开地址
                    HttpURLConnection huc=(HttpURLConnection) url.openConnection();
                    //设置连接超时
                    huc.setConnectTimeout(5000);
                    //设置读取超时
                    huc.setReadTimeout(5000);
                    //判断
                    if(huc.getResponseCode()==200){
                        //获取输入流
                        InputStream is=huc.getInputStream();
                        byte[] buffer=new byte[1024];
                        ByteArrayOutputStream bos = new ByteArrayOutputStream();
                        //将内容读取到ByteArrayOutputStream内存中
                        int len=-1;
                        while((len=is.read(buffer))!=-1){
                            bos.write(buffer, 0, len);
                        }
                        //关闭流
                        is.close();
                        //将流内容转成字符串
                        String json=bos.toString("gbk");
                        //
                        Gson gson=new Gson();
                        GroupBean bean=gson.fromJson(json, GroupBean.class);
                        list=bean.data;
                        handler.sendEmptyMessage(1);
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            };
        }.start();

    }

}

2秒之后跳转

new Handler().postDelayed(new Runnable() {
            public void run() {
                Intent intent=new Intent(OneActivity.this, MainActivity.class);
                startActivity(intent);
                finish();
            }
        }, 2000);