[英]JAVA HTTP Client and Serlvlet
I am working with Apache Tomcat and I want to send a data to a the http server and get response from HTTP server (from a servlet). 我正在使用Apache Tomcat,并且想将数据发送到http服务器并从HTTP服务器(从servlet)获得响应。
Problem : 问题 :
When I use the HTTP client to send the data, it seems the data are not delivered (the parameters sent are not displayed by the servlet). 当我使用HTTP客户端发送数据时,似乎没有传递数据(发送的参数未由servlet 显示 )。 When I simulate the same by a HTTP browser (Chrome), everything seems to be OK. 当我通过HTTP浏览器 (Chrome)模拟相同内容时,一切似乎正常。
Bellow are examples of my servlet and my http client. 贝娄是我的servlet和http客户端的示例。
My HTTP Servlet : 我的HTTP Servlet :
public class MyServlet extends HttpServlet {
public void doGet(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException {
PrintWriter out = res.getWriter();
out.println("This ervlet requires POST but received GET");
out.close();
}
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
for (String name : request.getParameterMap().keySet()) {
out.write("PARAMETER :" + name);
out.write("\n");
}
for (Part name : request.getParts()) {
out.write("MULTIPART PARAMETER :" + name.getName());
out.write("\n");
}
String p1 = request.getParameter("input1");
out.write("RECEIVED PARAMETER:" + p1);
out.write("\n");
out.close();
}
}
My HTTP client 我的HTTP客户端
/**
* Example how to use multipart/form encoded POST request.
*/
public class ClientMultipartFormPost {
public static void main(String[] args) throws Exception {
CloseableHttpClient httpclient = HttpClients.createDefault();
try {
HttpPost httppost = new HttpPost("http://example.com:8080" +
"/myservlet");
FileBody bin = new FileBody(new File("file1.txt"));
StringBody comment = new StringBody("A binary file of some kind", ContentType.TEXT_PLAIN);
HttpEntity reqEntity = MultipartEntityBuilder.create()
.addPart("bin", bin)
.addPart("input1", comment)
.build();
httppost.setEntity(reqEntity);
System.out.println("executing request " + httppost.getRequestLine());
CloseableHttpResponse response = httpclient.execute(httppost);
try {
System.out.println("----------------------------------------");
System.out.println(response.getStatusLine());
HttpEntity resEntity = response.getEntity();
if (resEntity != null) {
PrintWriter sWriter = new PrintWriter(System.out);
IOUtils.copy(resEntity.getContent(), sWriter, "UTF-8");
sWriter.close();
}
EntityUtils.consume(resEntity);
} finally {
response.close();
}
} finally {
httpclient.close();
}
}
}
OUTPUT: executing request POST 输出:执行请求POST
http://example.com:8080/myservlet HTTP/1.1 http://example.com:8080/myservlet HTTP / 1.1
---------------------------------------- HTTP/1.1 200 OK ---------------------------------------- HTTP / 1.1 200 OK
RECEIVED PARAMETER:null 接收参数:空
Browser Client (test) The broswer POST works as expected: 浏览器客户端(测试)浏览器POST按预期方式工作:
<form name="input" action="http://example.com:8080/servlet" method="post">
<input type="text" name="input1">
<input type="submit" value="Submit">
</form>
OUTPUT: PARAMETER :input1 输出:PARAMETER:input1
RECEIVED PARAMETER:AAAAAAAA 接收参数:AAAAAAAA
UPDATE: Browser code : 更新: 浏览器代码 :
Request URL:http://localhost:8080/servlet
Request Method:POST
Status Code:200 OK
Request Headersview parsed
POST /LyticsRemote/flexi HTTP/1.1
Host: localhost:8080
Connection: keep-alive
Content-Length: 10
Cache-Control: max-age=0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Origin: null
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/32.0.1700.102 Safari/537.36
Content-Type: application/x-www-form-urlencoded
Accept-Encoding: gzip,deflate,sdch
Accept-Language: cs,en-GB;q=0.8,en;q=0.6
Cookie: JSESSIONID=9BD73E186BC8A081AB87C8EF58483523
Form Dataview sourceview URL encoded
input1:aaa
Response Headersview source
Content-Length:41
Content-Type:text/html;charset=ISO-8859-1
Date:Fri, 31 Jan 2014 11:46:54 GMT
Server:Apache-Coyote/1.1
The solution was to add getParameters method to the servlet so the final code is : 解决的方法是将getParameters方法添加到servlet,因此最终代码为:
public class FlexiServlet extends HttpServlet {
private FileItem fileItem;
public void doGet(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException {
PrintWriter out = res.getWriter();
out.println("This ervlet requires POST but received GET");
out.close();
}
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
boolean success = getParameters(request, out);
out.write(" XXXXXXXXXXXXXXXXX" + success);
out.write(" XXXXXXXXXXXXXXXXX" + fileItem);
out.write("\n");
for (String name : request.getParameterMap().keySet()) {
out.write("PARAMETER :" + name);
out.write("\n");
}
for (Part name : request.getParts()) {
out.write("MULTIPART PARAMETER :" + name.getName());
out.write("\n");
}
String p1 = request.getParameter("input1");
out.write("RECEIVED PARAMETER:" + p1);
out.write("\n");
out.close();
}
public boolean getParameters(HttpServletRequest request, PrintWriter out) {
List fileItemsList = null;
try {
if (ServletFileUpload.isMultipartContent(request)) {
ServletFileUpload servletFileUpload = new ServletFileUpload(
new DiskFileItemFactory());
try {
fileItemsList = servletFileUpload.parseRequest(request);
} catch (FileUploadException ex) {
}
String optionalFileName = "";
Iterator it = fileItemsList.iterator();
while (it.hasNext()) {
FileItem fileItemTemp = (FileItem) it.next();
if (fileItemTemp.isFormField()) {
// for other form fields that are not multipart
// if (fileItemTemp.getFieldName().equals("commonName"))
// {
// commonName = fileItemTemp.getString();
// }
out.write("AAAAAAAAAAAA " + fileItemTemp.getFieldName());
} else {
if (fileItemTemp.getFieldName().equals("media_file")) {
fileItem = fileItemTemp;
}
out.write("BBBBBBBBBBBBBB " + fileItemTemp.getFieldName());
}
}
}
} catch (Exception e) {
}
return true;
}
}
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