Servlet Request获取数据及转发小案例
2019-10-26 本文已影响0人
JayMeWangGL
在杭州不太方便，只好写一写前些天学的方法巩固一下，案例包括获取获取网页中输入的数据，数据共享与转发。
转发
请求转发：一种在服务器内部的资源跳转方式
- 通过request对象获取请求转发器对象：RequestDispatcher getRequestDispatcher(String path)
- 使用RequestDispatcher对象来进行转发：forward(ServletRequest request, ServletResponse response)
资源共享及获取
- void setAttribute(String name,Object obj):存储数据
- Object getAttribute(String name):通过键获取值
- void removeAttribute(String name):通过键移除键值对
HTML5一个用表格写的简陋注册页面
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>登录</title>
</head>
<body>
<form action="/DemoServlet" method="post">
用户名<input type="text" name="username" placeholder="请输入用户名" ><br>
密码<input type="password" name="password" placeholder="请输入密码"><br>
爱好<input type="checkbox" name="hobby" value="study">学习<br>
<input type="submit" value="提交" >
</form>
</body>
</html>
效果图
第一个Servlet
@WebServlet("/DemoServlet")
public class DemoServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// String username = request.getParameter("username");
// System.out.println(username);
request.setCharacterEncoding("utf-8");//设置编码格式以防止中文乱码
Enumeration<String> parameterNames = request.getParameterNames();
while (parameterNames.hasMoreElements()){
String name = parameterNames.nextElement();
String value = request.getParameter(name);
System.out.println(name+"->"+value);
request.setAttribute(name,value);//数据存储以便在转发后可访问到数据
}
RequestDispatcher requestDispatcher = request.getRequestDispatcher("/DemoServlet2");//转发数据
requestDispatcher.forward(request,response);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
}
转发Servlet
@WebServlet("/DemoServlet2")
public class DemoServlet2 extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// String username = request.getParameter("username");
// System.out.println(username);
request.setCharacterEncoding("utf-8");
System.out.println("----转发----");
Object username = request.getAttribute("username");
Object password = request.getAttribute("password");
Object hobby = request.getAttribute("hobby");
System.out.println(username+" "+password+" "+hobby);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
}
数据测试及效果
注意：如果获取CheckBox 最好选用Map<String,String[]> getParameterMap()方法
其他方法会无法获取全部的值
