java如何得到GET和POST请求URL和参数列表

package com.zuidaima
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class GetParams extends HttpServlet {
private static final long serialVersionUID = 1L;

public GetParams() {
super();
}

protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
PrintWriter writer = response.getWriter();
writer.println("GET " + request.getRequestURL() + " "
+ request.getQueryString());

Map<String, String[]> params = request.getParameterMap();
String queryString = "";
for (String key : params.keySet()) {
String[] values = params.get(key);
for (int i = 0; i < values.length; i++) {
String value = values[i];
queryString += key + "=" + value + "&";
}
}
// 去掉最后一个空格
queryString = queryString.substring(0, queryString.length() - 1);
writer.println("GET " + request.getRequestURL() + "?" + queryString);
}

protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
PrintWriter writer = response.getWriter();
Map<String, String[]> params = request.getParameterMap();
String queryString = "";
for (String key : params.keySet()) {
String[] values = params.get(key);
for (int i = 0; i < values.length; i++) {
String value = values[i];
queryString += key + "=" + value + "&";
}
}
// 去掉最后一个&
queryString = queryString.substring(0, queryString.length() - 1);
writer.println("POST " + request.getRequestURL() + "?" + queryString);
}
}

/**
* 从上下文获取request
* @return
*/
public static HttpServletRequest getRequest(){
ServletRequestAttributes ra= (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
HttpServletRequest request =  ra.getRequest();
return request;
}