Java中http编程利用post、get与服务器交互Android按钮单击事件的四种写法

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Map;

public class HttpUtils {
    /*
     * 打开链接，确定连接；
     * */
    public static HttpURLConnection conn(String path,String method) throws IOException{
        
        URL url = new URL(path);
        HttpURLConnection con = (HttpURLConnection)url.openConnection();//打开连接
        
        con.setRequestMethod(method);
        con.setConnectTimeout(50000);
        con.setDoOutput(true);
        con.setDoInput(true);
        con.setRequestProperty("apikey", "db3c2b8c6a66509b6ee353d2dc09eea1");
        con.connect();
        if(con.getResponseCode()==200){
            return con;
        }
        return null;
    }
    /*
     * get或post请求获取服务器图片
     * */
    public static File connImg(String path,String method) throws IOException{
        File file = new File(""+new SimpleDateFormat("yyyyMMdd").format(new Date().getTime()));
        File f = new File(file,""+new Date().getTime()+"."+path.substring(path.lastIndexOf(".")+1));
        if(!file.exists()){
            file.mkdirs();
        }
        if(conn(path,method) instanceof HttpURLConnection){
            HttpURLConnection con = conn(path,method);
            InputStream is = con.getInputStream();
            FileOutputStream fos = new FileOutputStream(f);
            byte[] b = new byte[1024];
            int l = is.read(b);
            while(l!=-1){
                fos.write(b, 0, l);
                l = is.read(b);
            }
            is.close();
            fos.close();
        }
        return f;
    }
    
    /*
     * get或post抓取服务器数据
     * */
    public static String connData(String path,String method) throws IOException{
        String str=null;
        if(conn(path,method) instanceof HttpURLConnection){
            HttpURLConnection con = conn(path,method);
            
            InputStream is = con.getInputStream();
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            byte[] b = new byte[1024];
            int l = is.read(b);
            while(l!=-1){
                baos.write(b, 0, l);
                l = is.read(b);
            }
            str = new String(baos.toByteArray(),"UTF-8");
        }
        return str;
    }
    
    
    /*
     * get或post提交数据并接受服务器的返回值
     * */
    
    public static String connRequest(String path,String method,Map<String,String> para) throws IOException{
        String s=null;
        StringBuilder sb = new StringBuilder();
        for(Map.Entry<String,String> me:para.entrySet()){
            sb.append(me.getKey()+"="+URLEncoder.encode(me.getValue(),"UTF-8")+"&");
        }
        sb.deleteCharAt(sb.length()-1);
        
        path=path+"?"+sb;
        
        if(conn(path,method) instanceof HttpURLConnection){
            HttpURLConnection con = conn(path,method);
            InputStream is = con.getInputStream();
            byte[] b = new byte[1024];
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            int l = is.read(b);
            while(l!=-1){
                baos.write(b, 0, l);
                l=is.read(b);
            }
            s = new String(baos.toByteArray(),"UTF-8");
        }
        return s;    
    }
}