自学教程以下是通用的实例，使用 HttpServletRequest 的 getParameterNames() 方法读取所有可用的表单参数。该方法返回一个枚举，其中包含未指定顺序的参数名。
一旦我们有一个枚举，我们可以以标准方式循环枚举，使用 hasMoreElements() 方法来确定何时停止，使用 nextElement() 方法来获取每个参数的名称。
实例
package com.runoops.test;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Enumeration;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class ReadParamsServlet
*/
@WebServlet("/ReadParamsServlet")
public class ReadParamsServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public ReadParamsServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 设置响应内容类型
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
String title = "读取所有的表单数据";
String docType = "<!DOCTYPE html> \n";
out.println(docType +
"<html>\n" +
"<head><meta charset=\"utf-8\"><title>" + title + "</title></head>\n" +
"<body bgcolor=\"#f0f0f0\">\n" +
"<h1 align=\"center\">" + title + "</h1>\n" +
"<table width=\"100%\" border=\"1\" align=\"center\">\n" +
"<tr bgcolor=\"#949494\">\n" +
"<th>参数名称</th><th>参数值</th>\n"+
"</tr>\n");
Enumeration paramNames = request.getParameterNames();
while(paramNames.hasMoreElements()) {
String paramName = (String)paramNames.nextElement();
out.print("<tr><td>" + paramName + "</td>\n");
String[] paramValues =
request.getParameterValues(paramName);
// 读取单个值的数据
if (paramValues.length == 1) {
String paramValue = paramValues[0];
if (paramValue.length() == 0)
out.println("<td><i>没有值</i></td>");
else
out.println("<td>" + paramValue + "</td>");
} else {
// 读取多个值的数据
out.println("<td><ul>");
for(int i=0; i < paramValues.length; i++) {
out.println("<li>" + paramValues[i]);
}
out.println("</ul></td>");
}
out.print("</tr>");
}
out.println("\n</table>\n</body></html>");
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}现在，通过下面的表单尝试上面的 Servlet：
实例
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>runoops 自学教程</title>
</head>
<body>
<form action="ReadParamsServlet" method="POST" target="_blank">
<input type="checkbox" name="maths" checked="checked" /> 数学
<input type="checkbox" name="physics" /> 物理
<input type="checkbox" name="chemistry" checked="checked" /> 化学
<input type="submit" value="选择站点" />
</form>
</body>
</html>现在使用上面的表单调用 Servlet，将产生以下结果：
