java.io.IOException: Server returned HTTP response code: 500 for URL解决办法

今天遇到一个问题，写了一个客户端远程查询数据，结果报错了：

java.io.IOException: Server returned HTTP response code: 500 for URL: http://adserver.sinosns.cn/owner/owner_userAndOwner.action
客户端代码如下：

/**
* 执行一个HTTP POST请求，返回请求响应的HTML
*
* @param url请求的URL地址
* @param postData请求的查询参数
* @return 返回请求响应的HTML
*/
public static String doHttpPost(String url, String postData) {
String data = null;
try {
URL dataUrl = new URL(url);
HttpURLConnection con = (HttpURLConnection) dataUrl.openConnection();
//			con.setRequestMethod("POST");
//			con.setRequestProperty("Proxy-Connection", "Keep-Alive");
//			con.setDoOutput(true);
//			con.setDoInput(true);

con.setRequestMethod("POST");
con.setRequestProperty("Proxy-Connection", "Keep-Alive");
//			con.setRequestProperty("ContentType","text/xml;charset=utf-8");
con.setReadTimeout(50000);
con.setDoOutput(true);
con.setDoInput(true);
con.setUseCaches(false);

OutputStream os = con.getOutputStream();
DataOutputStream dos = new DataOutputStream(os);
dos.write(postData.getBytes("UTF-8"));
dos.flush();
dos.close();

InputStream is = con.getInputStream();
DataInputStream dis = new DataInputStream(is);
byte d[] = new byte[dis.available()];
dis.read(d);
data = new String(d,"UTF-8");
//			 System.out.println(data);
con.disconnect();
} catch (Exception ex) {
ex.printStackTrace();
}
return data;
}

服务器端代码：

CustomerModel customerModel = customerDao.getObjectByID(CustomerModel.class, Integer.valueOf(userid));
OwnerModel ownerModel = ownerDao.getObjectByID(OwnerModel.class, Integer.valueOf(ownerid));

if(null != customerModel){
object.put("userMac", customerModel.getMac());
object.put("userPhone",customerModel.getCustName());
}else {
object.put("userMac", "0");
object.put("userPhone","0");
}
if(null  != ownerModel){
if(null==ownerModel.getIndustryId()){
object.put("industry", "0");
}
else {
object.put("industry", ownerModel.getIndustryId().toString());
}
object.put("province", ownerModel.getProvinceId().toString());
object.put("city", ownerModel.getCityId().toString());
object.put("area", ownerModel.getAreaId().toString());
} else {
object.put("industry", "0");
object.put("province", "0");
object.put("city", "0");
object.put("area", "0");
}
return object.toString();

结果，因为传递的参数为空字符串，导致服务器端程序出现异常，没有数据返回客户端。所以在执行到

OutputStream os = con.getOutputStream();

这句代码的时候就报错了。

我的解决办法是在服务器端加上异常处理，并且在catch里面返回一个自定义的对象

这样就算发生异常，客户端也能去得到数据