How to get an HTTP POST request body as a Java String at the server side?

Question

The getRequestBody method of the HttpExchange object returns an InputStream. There is still much work for correctly read the "Body". Is it a Java library + object + method that goes one more step ahead and returns the body (at the server side) as a ready-to-use Java String?

Solution 1

InputStreamReader isr =  new InputStreamReader(t.getRequestBody(),"utf-8");
BufferedReader br = new BufferedReader(isr);

// From now on, the right way of moving from bytes to utf-8 characters:

int b;
StringBuilder buf = new StringBuilder(512);
while ((b = br.read()) != -1) {
    buf.append((char) b);
}

br.close();
isr.close();

// The resulting string is: buf.toString()
// and the number of BYTES (not utf-8 characters) from the body is: buf.length()

Solution 2

If you are using Spring MVC, you can use the @RequestBody annotation on a method parameter which is of type String. For example.

@RequestMapping(value = "/something", method = RequestMethod.POST)
public void doSomething(@RequestBody String requestBodyString) {
    // does something..
}

Solution 3

Did you try this ?

 InputStreamReader isr =  new InputStreamReader(exchange.getRequestBody(),"utf-8");
 BufferedReader br = new BufferedReader(isr);
 String value = br.readLine();

Solution 4

You can use Commons IO's org.apache.commons.io.IOUtils.toString(InputStream, String) to do this in one line. (It might not work with HTTP keep-alive though)

Edit:

If you want to go straight to JSON, there are a bunch of Web Service stacks that will do the unmarshalling for you. Try

Spring: http://www.cribbstechnologies.com/2011/04/08/spring-mvc-ajax-web-services-part-2-attack-of-the-json-post/

CXF / JAX-RS: http://cxf.apache.org/docs/jax-rs-data-bindings.html#JAX-RSDataBindings-JSONsupport

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Comments

[Joshua]

Yes, I tried. The problem is that the body does not end with CR/LF. I found a solution by using the read(char[]) method with the content-length and it approximately works. I wonder if it is not a method that performs this reading job to the end.

[artbristol]

You should get the encoding from the HTTP headers, not just assume it's UTF-8.

[Joshua]

It is Json. I decipher it and insert the data in a MySQL database.

[Joshua]

Is it a way to go straight to Json? It would be great!

[Joshua]

StringBuilder buf = new StringBuilder();

[Shreyas SG]

what is 't' here? InputStreamReader(t.getRequestBody(),"utf-8");