POST 请求出现异常！java.io.IOException: Server returned HTTP response code: 400 for URL

发送 POST 请求出现异常！java.io.IOException: Server returned HTTP response code: 400 for URL: http://111.123.138.247:8080/jobScheduler/pendingJobjava.io.IOException: Server returned HTTP response code: 400 for URL: http://111.123.138.247:8083/jobScheduler/pendingJob
  at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1627)
  at com.ulearning.ulms.util.HttpClientUtil.sendPost(HttpClientUtil.java:233)
  at com.ulearning.ulms.homework.action.TutorHomeworkAction.pushMessage(TutorHomeworkAction.java:799)
  at com.ulearning.ulms.homework.action.TutorHomeworkAction.saveOrUpdateHomework(TutorHomeworkAction.java:742)
  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  at java.lang.reflect.Method.invoke(Method.java:606)
  at org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:280)
  at org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:216)
  at com.ulearning.ulms.homework.action.TutorHomeworkAction.execute(TutorHomeworkAction.java:142)
  at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)
  at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
  at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1480)
  at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:524)
  at javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
  at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
  at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
  at com.ulearning.ulms.core.filter.JSPSupportFilter.doFilter(JSPSupportFilter.java:51)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
  at com.ulearning.ulms.util.RolePermissionFilter.doFilter(RolePermissionFilter.java:72)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
  at com.ulearning.ulms.util.XssFilter.doFilter(XssFilter.java:23)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
  at com.ulearning.ulms.util.BehaviorRecordsFilter.doFilter(BehaviorRecordsFilter.java:84)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
  at com.ulearning.ulms.util.i18n.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:103)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
  at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
  at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
  at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
  at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
  at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
  at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
  at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
  at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
  at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
  at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
  at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
  at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)

com.alibaba.fastjson.JSONObject jsonStr = new com.alibaba.fastjson.JSONObject();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm");
SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
JSONObject jsonStr = new JSONObject();
Date dBefore = new Date();
Calendar calendar = Calendar.getInstance(); //得到日历
calendar.setTime(ah.getEndTime());//把当前时间赋给日历
calendar.add(Calendar.DAY_OF_MONTH, -1); //设置为前一天
dBefore = calendar.getTime(); //得到前一天的时间
String defaultStartDate = sdf.format(dBefore); //格式化前一天
jsonStr.put("pushTime", defaultStartDate );
jsonStr.put("content", "你好");
try {
  HttpClientUtil.sendPost(url, jsonStr.toString(),null,HttpClientUtil.CONTENTTYPE);
} catch (Exception e) {
  e.printStackTrace();
}

 public static String sendPost(String url, String param, String contentType) {
      OutputStreamWriter out = null;
      BufferedReader in = null;
      String result = "";
      try {
          URL realUrl = new URL(url);
          // 打开和URL之间的连接
          HttpURLConnection conn = (HttpURLConnection) realUrl.openConnection();
          // 设置通用的请求属性
          conn.setRequestProperty("accept", "*/*");
          conn.setRequestProperty("connection", "Keep-Alive");
          conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
          conn.setRequestProperty("Content-Type", contentType);
          // 发送POST请求必须设置如下两行
          conn.setDoOutput(true);
          conn.setDoInput(true);
        /*************************************************************************/  
          // 获取URLConnection对象对应的输出流
          // out = new PrintWriter(conn.getOutputStream());
          out = new OutputStreamWriter(conn.getOutputStream(), "utf-8"); // 8859_1
    /*************************************************************************/  
          out.write(param); // post的关键所在
          // 发送请求参数
          // out.print(param);
          // flush输出流的缓冲
          out.flush();
          // 定义BufferedReader输入流来读取URL的响应
          int code = conn.getResponseCode();
          if(code == 200) {
              in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
          }else{
              in = new BufferedReader(new InputStreamReader(conn.getErrorStream()));
          }
          String line;
          while ((line = in.readLine()) != null) {
              result += line;
          }
      } catch (Exception e) {
          System.out.println("发送 POST 请求出现异常！" + e);
          e.printStackTrace();
      }
      // 使用finally块来关闭输出流、输入流
      finally {
          try {
              if (out != null) {
                  out.close();
              }
              if (in != null) {
                  in.close();
              }
          } catch (IOException ex) {
              ex.printStackTrace();
          }
      }
      return result;
    }