使用Java程序发送post请求给servlet

使用Java程序发送post请求给servlet

我们需要完成的工作其实很简单，就是将一个文件流以post的方式发送到服务器或者也可以是客户端。

java发送请求是通过HttpURLConnection来实现的：

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
public class SendPostRequest {
 static String sessionId = "";
 public static void main(String[] args) throws Exception {
  // TODO Auto-generated method stub
  URL url = new URL("http://localhost:8080/GetRequest/");
  HttpURLConnection connection = (HttpURLConnection) url.openConnection();
  connection.setDoOutput(true);
  // Read from the connection. Default is true.
  connection.setDoInput(true);
  // Set the post method. Default is GET
  connection.setRequestMethod("POST");
  // Post cannot use caches
  // Post 请求不能使用缓存
  connection.setUseCaches(false);
  // This method takes effects to
  // every instances of this class.
  // URLConnection.setFollowRedirects是static函数，作用于所有的URLConnection对象。
  // connection.setFollowRedirects(true);
  // This methods only
  // takes effacts to this
  // instance.
  // URLConnection.setInstanceFollowRedirects是成员函数，仅作用于当前函数
  connection.setInstanceFollowRedirects(false);
  // Set the content type to urlencoded,
  // because we will write
  // some URL-encoded content to the
  // connection. Settings above must be set before connect!
  // 配置本次连接的Content-type，配置为application/x-www-form-urlencoded的
  // 意思是正文是urlencoded编码过的form参数，下面我们可以看到我们对正文内容使用URLEncoder.encode
  // 进行编码
  connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
  // 连接，从postUrl.openConnection()至此的配置必须要在connect之前完成，
  // 要注意的是connection.getOutputStream会隐含的进行connect。
  connection.connect();
  Long sendTime = System.currentTimeMillis();
  DataOutputStream out = new DataOutputStream(connection.getOutputStream());
  // 要传的参数
  String content = URLEncoder.encode("username", "UTF-8") + "=" + URLEncoder.encode("XXX", "UTF-8");
  content += "&" + URLEncoder.encode("password", "UTF-8") + "=" + URLEncoder.encode("XXXX", "UTF-8");
  content += "&" + URLEncoder.encode("sendTime", "UTF-8") + "=" + URLEncoder.encode(sendTime.toString(), "UTF-8");
  //读海量文件
  StringBuilder postStrBuf = new StringBuilder();
  for (int i = 0; i < 1; i++) {
   File file = new File("E:/toodou_work/yuliang.csv");
   BufferedReader reader = null;
   String postStr = null;
   reader = new BufferedReader(new FileReader(file));
   while ((postStr = reader.readLine()) != null) {
    postStrBuf.append(postStr);
   }
  }
  content = content + "&" + URLEncoder.encode("file", "UTF-8") + "=" + URLEncoder.encode(postStrBuf.toString(), "UTF-8");
  // DataOutputStream.writeBytes将字符串中的16位的unicode字符以8位的字符形式写道流里面
  out.writeBytes(content);
  out.flush();
  out.close(); // flush and close
  //Get Session ID
  String key = "";
  if (connection != null) {
   for (int i = 1; (key = connection.getHeaderFieldKey(i)) != null; i++) {
    if (key.equalsIgnoreCase("set-cookie")) {
     sessionId = connection.getHeaderField(key);
     sessionId = sessionId.substring(0, sessionId.indexOf(";"));
    }
   }
  }
  connection.disconnect();
 }
}