关于使用纯java获取http url请求返回的信息

  1 import java.io.ByteArrayOutputStream;
  2 import java.io.IOException;
  3 import java.io.InputStream;
  4 import java.io.OutputStream;
  5 import java.net.HttpURLConnection;
  6 import java.net.URL;
  7 
  8 
  9 public class HttpTest {
 10 
 11     
 12     public static void main(String[] args) {
 13         String path = "http://127.0.0.1:8080/demo/test.servlet" ;
 14 //        String path = "https://www.baidu.com/" ;//只能支持get请求
 15         
 16         HttpURLConnection httpURLConnection = null ;
 17         ByteArrayOutputStream byteArrayOutputStream = null ;
 18         OutputStream outputStream = null ;
 19         InputStream inputStream = null ;
 20         URL url = null ;
 21         
 22         //从输出流中获取读取到数据(服务端返回的)
 23         String message = null ;
 24         try {
 25             //请求的url
 26             url = new URL(path);
 27             
 28             //创建http链接
 29             httpURLConnection = (HttpURLConnection) url.openConnection();
 30    
 31             //设置超时时间
 32             httpURLConnection.setConnectTimeout(5000);// 5 秒
 33             httpURLConnection.setReadTimeout(5000);
 34             
 35             //设置请求的方法类型
 36             httpURLConnection.setRequestMethod("POST");
 37             
 38             //设置通用的请求属性 设置请求格式
 39             httpURLConnection.setRequestProperty("contentType", "utf-8"); 
 40             httpURLConnection.setRequestProperty("content-type", "application/x-www-form-urlencoded");
 41 
 42             //设置发送数据
 43             httpURLConnection.setDoOutput(true);
 44             //设置接受数据
 45             httpURLConnection.setDoInput(true);
 46             
 47             //发送数据,使用输出流
 48             outputStream = httpURLConnection.getOutputStream();
 49             outputStream.write(new String("name=zhangshang&pwd=123").getBytes());
 50             outputStream.flush() ;
 51 //        //发送数据
 52             if (httpURLConnection.getResponseCode() == 200) {//成功
 53                 //接收数据
 54                 inputStream = httpURLConnection.getInputStream();
 55                 //定义字节数组
 56                 byte[] b = new byte[1024];
 57                 //定义一个输出流存储接收到的数据
 58                 byteArrayOutputStream = new ByteArrayOutputStream();
 59                 //开始接收数据
 60                 int len = 0;
 61                 while (true) {
 62                     len = inputStream.read(b);
 63                     if (len == -1) {
 64                         //数据读完
 65                         break;
 66                     }
 67                     byteArrayOutputStream.write(b, 0, len);
 68                 }
 69             }else{//失败
 70                 System.err.println("异常HTTP状态码 : "+httpURLConnection.getResponseCode());
 71                 //接收数据
 72                 inputStream = httpURLConnection.getInputStream();
 73                 //定义字节数组
 74                 byte[] b = new byte[1024];
 75                 //定义一个输出流存储接收到的数据
 76                 byteArrayOutputStream = new ByteArrayOutputStream();
 77                 //开始接收数据
 78                 int len = 0;
 79                 while (true) {
 80                     len = inputStream.read(b);
 81                     if (len == -1) {
 82                         //数据读完
 83                         break;
 84                     }
 85                     byteArrayOutputStream.write(b, 0, len);
 86                 }
 87             
 88             }
 89             message = byteArrayOutputStream.toString("utf-8");
 90         } catch (Exception e) {
 91             e.printStackTrace();
 92         } finally{
 93             if(null != byteArrayOutputStream){
 94                 try {
 95                     byteArrayOutputStream.close() ;
 96                 } catch (IOException e) {
 97                     e.printStackTrace();
 98                 }
 99             }
100             if(null != inputStream){
101                 try {
102                     inputStream.close() ;
103                 } catch (IOException e) {
104                     e.printStackTrace();
105                 }
106             }
107             if(null != outputStream){
108                 try {
109                     outputStream.close() ;
110                 } catch (IOException e) {
111                     e.printStackTrace();
112                 }
113             }
114             if(null != httpURLConnection){
115                 httpURLConnection.disconnect() ;
116             }
117         }
118         System.out.println(message);
119     }
120 }