import com.google.gson.Gson;

import org.apache.struts2.ServletActionContext;

import javax.servlet.ServletRequest;

import java.io.*;

/**

 * Created by sky.tian on 2015/1/12.

 */

public class Test {

    private static final int DEFAULT_BUFFER_SIZE = 1024 * 4;

    private static final Gson gson = new Gson();

    public <T> T parseRequestBody(Class<T> type) throws IOException {

        ServletRequest request = ServletActionContext.getRequest();

        InputStream inputStream = request.getInputStream();

        String json = getRequestBodyJson(inputStream);

        return gson.fromJson(json, type);

    }

    /**

     * 得到HTTP请求body中的JSON字符串

     * @param inputStream

     * @return

     * @throws IOException

     */

    private String getRequestBodyJson(InputStream inputStream) throws IOException {

        Reader input = new InputStreamReader(inputStream);

        Writer output = new StringWriter();

        char[] buffer = new char[DEFAULT_BUFFER_SIZE];

        int n = 0;

        while(-1 != (n = input.read(buffer))) {

            output.write(buffer, 0, n);

        }

       return output.toString();

    }

}