HttpURLConnection的使用

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

/**
 * Http工具类
 * 
 * @author Administrator
 * 
 */
public class HttpUtils {
    /**
     * 网络请求
     * @param urlpath 地址
     * @return
     */
    public static byte[] request(String urlpath) {
        ByteArrayOutputStream baos=null;
        try {
            baos=new ByteArrayOutputStream();
            //1创建URL
            URL url=new URL(urlpath);
            //2调用openConnection()
            HttpURLConnection connection=(HttpURLConnection) url.openConnection();
            //3设置请求参数
            connection.setConnectTimeout(10000);
            connection.setReadTimeout(10000);
            //4建立连接
            connection.connect();
            //5处理响应结果
            if(connection.getResponseCode()==200){
                InputStream is=connection.getInputStream();
                byte[] buf=new byte[1024*4];
                int len=0;
                while((len=is.read(buf))!=-1){
                    baos.write(buf,0,len);
                }
                is.close();
            }
            return baos.toByteArray();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return null;
    }
}