java Servlet 参数和 doPut
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Servlet parameters and doPut
提问by Erick Fleming
Trying to get parameters from a PUT request using HttpServlet#doPut:
尝试使用 HttpServlet#doPut 从 PUT 请求中获取参数：
public void doPut(HttpServletRequest request, HttpServletResponse response) {
String name = request.getParameter("name");
// name is null
}
Using curl to send the request:
使用 curl 发送请求：
curl -X PUT \
--data "name=batman" \
--header "Content-Type: text/plain" http://localhost:8080/sample.html
works fine with using doGet and GET curl request. Am I missing something?
使用 doGet 和 GET curl 请求可以正常工作。我错过了什么吗？
回答by Erick Fleming
Based on comments and further research I realized that the Servlet cannot assume anything about the data being put onto the server and therefore, will not parse name/value pairs.
基于评论和进一步的研究，我意识到 Servlet 不能假设任何关于放入服务器的数据，因此不会解析名称/值对。
The following solution seems to be the proper way to handle any data passed via PUT, and can be parsed as XML, Name/Value, or whatever.
以下解决方案似乎是处理通过 PUT 传递的任何数据的正确方法，并且可以解析为 XML、名称/值或其他任何内容。
BufferedReader br = new BufferedReader(new InputStreamReader(req.getInputStream());
String data = br.readLine();
回答by Jan Bodnar
Unlike in doGet()and doPost()methods, we are not able to get the request parameters using the getParameter()method in doPut()and doDelete()methods. We need to retrieve them manually from the input stream.
与 indoGet()和doPost()方法不同，我们无法使用getParameter()indoPut()和doDelete()methods 方法获取请求参数。我们需要从输入流中手动检索它们。
The following method retrieves request parameters and returns them in a map:
以下方法检索请求参数并在映射中返回它们：
public static Map<String, String> getParameterMap(HttpServletRequest request) {
BufferedReader br = null;
Map<String, String> dataMap = null;
try {
InputStreamReader reader = new InputStreamReader(
request.getInputStream());
br = new BufferedReader(reader);
String data = br.readLine();
dataMap = Splitter.on('&')
.trimResults()
.withKeyValueSeparator(
Splitter.on('=')
.limit(2)
.trimResults())
.split(data);
return dataMap;
} catch (IOException ex) {
Logger.getLogger(Utils.class.getName()).log(Level.SEVERE, null, ex);
} finally {
if (br != null) {
try {
br.close();
} catch (IOException ex) {
Logger.getLogger(Utils.class.getName()).log(Level.WARNING, null, ex);
}
}
}
return dataMap;
}
The example uses Google's Guava library to parse the parameters.
For a complete example containing doGet(), doPost(), doPut()and doDelete()methods, you can read my Using jsGrid tutorial.
该示例使用 Google 的 Guava 库来解析参数。对于包含一个完整的例子doGet()，doPost()，doPut()和doDelete()方法，你可以阅读我的使用jsGrid教程。
回答by Adeel Ansari
What do you mean by doPut()is not working? As far as I know, it doesn't work like doGet()or doPost(), where you have request parameters and stuff.
你说的doPut()不工作是什么意思？据我所知，它不像doGet()or那样工作doPost()，在那里你有请求参数和东西。
PUT can be used to put something on the server. In particular, the PUT operation allows a client to place a file on the server and is similar to sending a file by FTP. Check out this example, I found on JGuru.
PUT 可用于在服务器上放置一些东西。特别是 PUT 操作允许客户端将文件放置在服务器上，类似于通过 FTP 发送文件。看看这个例子，我在 JGuru 上找到的。
->GET /file.dat HTTP/1.1
<-HTTP/1.1 404 Not Found
->PUT /file.dat HTTP/1.1
Content-Length: 6
Content-Type: text/plain
Hello!
<-HTTP/1.1 200 OK
->GET /file.dat HTTP/1.1
<-HTTP/1.1 200 OK
Content-Length: 6
Content-Type: text/plain
Hello!
