无法从HttpClient向Servlet doPost方法发送请求

Question

I have created a Servlet class named SampleServlet in a new dynamic web project . I have started the server in debug mode. Below is the code in my Servlet-

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    BufferedReader reader = request.getReader();
    System.out.println(reader.readLine());

}

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    BufferedReader b = new BufferedReader(request.getReader());  
    System.out.println(reader.readLine());

}

And my web.xml file is like this-

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>ServletExample</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  <servlet>
    <description></description>
    <display-name>SampleServlet</display-name>
    <servlet-name>SampleServlet</servlet-name>
    <servlet-class>com.servlet.example.SampleServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>SampleServlet</servlet-name>
    <url-pattern>/SampleServlet</url-pattern>
  </servlet-mapping>
</web-app>

I have put the breakpoint in both the methods above. As soon as I hit this url from the browser-

http://localhost:8080/ServletExample/SampleServlet

my breakpoint always gets hit in doGet method.

Now I have created a new Java Project in the eclipse which is my client and which will call the servlet doPost method as I need to pass an XML file to my servlet as a request.

Below is my code-

public static void main(String[] args) {

    HttpPost post = new HttpPost("http://localhost:8080/ServletExample/SampleServlet");
    post.setHeader("Content-Type", "application/xml");
    post.setEntity(new StringEntity(generateNewXML()));
    HttpClient client = new DefaultHttpClient();
    HttpResponse response = client.execute(post);
}

But somehow as soon as I run my above main program as a Java Application, it doesn't hit the breakpoint I have put in my servlet class. And I am not sure why it is happening and no exceptions is getting thrown. Any idea why it is happening?

Answer 1

Your contentType is wrong, to upload a file to a web server you need to specify the multipart format.

See https://stackoverflow.com/a/1068132/305116 for a problem like yours, and http://evgeny-goldin.com/blog/uploading-files-multipart-post-apache/ for a little tutorial.

So in your main function you need something like this for it to work:

public static void main(String[] args) {

    HttpPost post = new HttpPost("http://localhost:8080/ServletExample/SampleServlet");
    MultipartEntity entity = new MultipartEntity();
    entity.addPart( "someXMLfile", new StringBody(generateNewXML(), "application/xml",
        Charset.forName( "UTF-8" )));
    post.setEntity(entity);

    HttpClient client = new DefaultHttpClient();
    HttpResponse response = client.execute(post);
}