琢磨一天了,想看看你们怎么配置的。
12条回答 默认 最新
- lianjie_c 2018-05-10 10:03关注
Servlet.java
public class Servlet extends HttpServlet { /** * */ private static final long serialVersionUID = 1L; public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("UTF-8"); String name = request.getParameter("username"); String url = "jdbc:mysql://localhost:3306/test"; String user = "root"; String password = "root"; Connection conn = null; PreparedStatement pst = null; ResultSet rs = null; response.setContentType("text/html"); response.setCharacterEncoding("UTF-8"); OutputStream os = response.getOutputStream(); try { Class.forName("com.mysql.jdbc.Driver"); conn = DriverManager.getConnection(url, user, password); String sql = "select username from test where username=? "; pst = conn.prepareStatement(sql); pst.setString(1, name); rs = pst.executeQuery(); if(rs.next()) { System.out.println("用户名"+name+"已存在"); String message = "用户名"+name+"已存在"; os.write(message.getBytes("UTF-8")); os.close(); return; } System.out.println(name+"用户名不存在"); String message = "success"; os.write(message.getBytes("UTF-8")); os.close(); } catch (Exception e) { e.printStackTrace(); String message = "系统异常"; os.write(message.getBytes("UTF-8")); os.close(); } finally { if(rs!=null) { try { rs.close(); rs = null; } catch (SQLException e) { e.printStackTrace(); } } if(pst!=null) { try { pst.close(); pst = null; } catch (SQLException e) { e.printStackTrace(); } } if(conn!=null) { try { conn.close(); conn = null; } catch (SQLException e) { e.printStackTrace(); } } } } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doGet(request, response); } }
jsp
<body> <form id="form"> 用户名:<input type="text" name="username" id="username" onblur="checkUsername(this.value)"/><br> 密码:<input type="password" name="password" id="password" /><br> 验证码:<input type="text" name="code" id="code" /><br> </form> <script type="text/javascript" src="http://apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js"></script> <script type="text/javascript"> function checkUsername(username) { if($.trim(username)=="") { alert("用户名为空"); return; } $.ajax({ url:"Servlet", type:"post", dataType:"text", data:{ username:username }, success:function(data){ if(data!="success") { alert(data); } } }); } </script> </body>
web.xml
<servlet-mapping> <servlet-name>Servlet</servlet-name> <url-pattern>/Servlet</url-pattern> </servlet-mapping>
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