（二）Servlet 表單數據

時間 2019-12-23

標籤 servlet 表單數據欄目 Tomcat 简体版

原文原文鏈接

使用 Servlet 讀取表單數據

在Web應用中，對於客戶端數據的收集一般會使用表單來進行。當用戶端請求到達服務器時，Servlet主要經過HttpServletRequest對象的三種方法來獲取用戶請求的參數：javascript

(1)Public String getParameter(String name)：用來獲取表單單個請求參數的值。html

(2)Public Enumeration getParameterNames()：若是您想要獲得當前請求中的全部參數的完整列表，則調用該方法。java

(3)Public String[] getParameterValues(String name)：若是參數name的值不止一個，則調用該方法，並返回多個值。服務器

示例以下：post

(1)源代碼this

submitForm.htmlspa

<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title>Submit From</title>
	</head>
	<body>
		<form action="showParameter" method="get" id="submitFrom">
			<label for="method">提交方式</label>
			<select id="method">
				<option value="get" name="submitmethod" selected="selected">get</option>
				<option value="post" name="submitmethod">post</option>
			</select>
			<br/>
			<script type="text/javascript">
				document.getElementById("method").onchange = function(){
					var index = this.selectedIndex;
					var selMethod = this.options[index].value;
					document.getElementById("submitFrom").method = selMethod;
				}
			</script>
			<label for="man">男</label>
			<input type="checkbox" value="man" id="sex" name="sex">
			<label for="woman">女</label>
			<input type="checkbox" value="woman" id="woman" name="sex"><br>
			<label for="name">姓名</label>
			<input type="text" id="name" name="name"><br>
			<label for="age">年齡</label>
			<input type="text" id="age" name="age"><br>
			<input type="submit" name="submit">
		</form>
	</body>
</html>

showParameter.javacode

package cn.border.parameter;
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 showParameter
 */
@WebServlet("/showParameter")
public class showParameter extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public showParameter() {
        super();
        // TODO Auto-generated constructor stub
    }
	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		//解決中文參數亂碼
		request.setCharacterEncoding("utf-8");
		response.setContentType("text/html;charset=utf-8");
		
		PrintWriter out = response.getWriter();
		Enumeration<String> parameterNames = request.getParameterNames();
		while (parameterNames.hasMoreElements()) {
			String parameterName = (String) parameterNames.nextElement();
			out.println(parameterName+"   :   ");
			String[] parameterValues = request.getParameterValues(parameterName);
			if (parameterValues.length == 1) { 		//只有一個值
				String parameterValue = parameterValues[0];
				if(parameterValue.length() == 0){
					out.println("值爲空");
				}else {
					out.print(parameterValue);
				}
			} else {								//
				for (String parametervalue : parameterValues) {
					out.println(parametervalue+" | ");
				}
			}
			out.println("<br>");
		}
	}
	/**
	 * @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);
	}
}

(2)運行結果orm