Servlet简单例子：前后端通信

JJU_干干

Servlet简单例子：前后端通信

需要做的事：html代码 + Servlet代码 + 运行操作

html代码：一个简陋的表单代码

要点：

给form添加action属性，属性值为：/动态web项目名/Servlet类映射地址
给input添加name属性
html文件要放到Web项目中的WebContent文件夹下

代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>一个简单表单</title>
</head>
<body>
	<!-- action赋值为：/动态web项目名/Servlet类映射地址 -->
    <form action="/Servlet_01/Submit_Servlet">
        <div>
            <label for="">用户名</label>
            
            <!-- name属性通过submit提交给action对应的服务器 -->
            <input type="text" name="userName">
        </div>

        <div>
            <label for="">密码</label>
            <input type="text" name="password">
        </div>

        <div>
            <button type="button">取消</button>
            <button type="submit">登入</button>
        </div>

    </form>
</body>
</html>

代码效果：

我的项目文件树如下：

Servlet代码

要点：

防止请求和回复因用中文而出现乱码，操作为以下两点
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset = utf-8");
通过request.getParameter("name属性值")获取容器中的参数

代码：

package case_01;

import java.io.IOException;
import java.io.PrintWriter;

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 Submit_Servlet
 */
@WebServlet("/Submit_Servlet")
public class Submit_Servlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public Submit_Servlet() {
        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
		//response.getWriter().append("Served at: ").append(request.getContextPath());
		// 以下两条语句防止输入中文出现乱码
		request.setCharacterEncoding("utf-8");
		response.setContentType("text/html;charset = utf-8");
		
		// 用request的getParameter方法获取容器中的参数
		String userName = request.getParameter("userName");
		PrintWriter out = response.getWriter();
		out.println("用户名："+userName);
	}

	/**
	 * @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);
	}

}