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【ajax】ajax异步实现用户注册验证

从前台到后台实现简单用户注册检查用户是否存在

1.编写domain

public class User {
	private String username;
	private String password;
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
}

2.编写dao

public class UserDao {
	/**
	 * 通过用户名获取用户
	 * @param username
	 * @return
	 * @throws SQLException 
	 */
	public User getUserByUsername4Ajax(String username) throws SQLException {
		
		QueryRunner qr = new QueryRunner(DataSourceUtils.getDataSource());
		String sql = "select * from user where username = ? limit 1";
		User user = qr.query(sql, new BeanHandler<>(User.class), username);
		return user;
	}
}

3.编写service

public class UserService {
	/**
	 * 检测用户名是否被占用
	 * @param username
	 * @return
	 * @throws SQLException
	 */
	public User checkUsername4Ajax(String username) throws SQLException{
		UserDao userDao = new UserDao();
		return userDao.getUserByUsername4Ajax(username);
	}
}

4.编写controller

public class CheckUsername4AjaxServlet extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		// 0.设置编码
		
		// 1.接收用户名
		String username = request.getParameter("username");
		username = new String(username.getBytes("iso-8859-1"),"utf-8");
		System.out.println(username);
		// 2.调用service 完成查询 返回值user
		UserService userService = new UserService();
		User user = null;
		try {
			user = userService.checkUsername4Ajax(username);
		} catch (SQLException e) {
			e.printStackTrace();
		}
		
		// 3.写回信息
		if (user == null) {
			response.getWriter().println("1");
		} else {
			response.getWriter().println("0");
		}
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doGet(request, response);
	}

}

5.编写注册页面

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    
    <title>用户注册</title>
	<script type="text/javascript" src="${pageContext.request.contextPath }/js/jquery-1.11.3.min.js"></script>
  
  
  	<script type="text/javascript">
  	
  		$(function() {
  			// 给username派发一个失去焦点事件发送ajax请求
  			$("input[name='username']").blur(function() {
  				// 获取输入的文本内容
  				var $value = $(this).val();
  				var url = "${pageContext.request.contextPath}/checkUsername4Ajax";
  				var params = "username="+$value;
  				$.get(url, params, function(d) {
  					if (d == 1) {
						$("#username_msg").html("<font color='green'>用户名可以使用</font>");
					} else {
						$("#username_msg").html("<font color='red'>用户名已被占用</font>");
					}
  				});
  			});
  		
  		});
  	</script>
  </head>
  
  <body>
    <form action="" method="post" >
    	<table border="0" align="center" cellpadding="0">
    		<tr >
    			<td colspan="2" align="center"><h2>用户注册</h2></td>
    		</tr>
    		<tr>
    			<td>用户名：</td>
    			<td><input type="text" name="username"/></td>
    			<td><span id="username_msg"></span></td>
    		</tr>
    		<tr>
    			<td>密码：</td>
    			<td><input type="password" name="password"/></td>
    			<td></td>
    		</tr>
    		<tr>
    			<td colspan="3" align="center"><input type="submit" name="submit" id="submit" value="提交"/><input type="reset" name="reset" value="重置"/></td>
    		</tr>
    	</table>
    </form>
    
  </body>
</html>

附录

1.DataSourceUtils工具类

public class DataSourceUtils {
	private static ComboPooledDataSource ds = new ComboPooledDataSource();
	
	private static ThreadLocal<Connection> tl = new ThreadLocal<>();
	
	/**
	 * 获取数据源
	 * @return 连接池
	 */
	public static DataSource getDataSource() {
		return ds;
	}
	
	/**
	 * 从当前线程上获取连接
	 * @return 连接
	 * @throws SQLException
	 */
	public static Connection getConnection() throws SQLException {
		Connection conn = tl.get();
		
		if (conn == null) {
			// 第一次获取，创建一个连接和当前的线程绑定
			conn = ds.getConnection();
			
			// 绑定
			tl.set(conn);
		}
		return conn;
	}
	
	/**
	 * 释放资源
	 * @param conn 连接
	 * @param st 语句执行者
	 * @param rs 结果集
	 */
	public static void closeResource(Connection conn, Statement st, ResultSet rs) {
		
		closeResource(st, rs);
		closeConn(conn);
	}

	/**
	 * 释放连接
	 * @param conn 连接
	 */
	private static void closeConn(Connection conn) {
		if (conn != null) {
			try {
				conn.close();
				// 和当前的线程解绑
				tl.remove();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			conn = null;
		}
	}

	private static void closeResource(Statement st, ResultSet rs) {
		closeResultSet(rs);
		closeStatement(st);
	}

	private static void closeStatement(Statement st) {
		if (st != null) {
			try {
				st.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			st = null;
		}
		
	}

	private static void closeResultSet(ResultSet rs) {
		if (rs != null) {
			try {
				rs.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			rs = null;
		}
	}
	
	/**
	 * 开启事务
	 * @throws SQLException
	 */
	public static void startTransaction() throws SQLException{
		// 获取连接
		// 开始事务
		getConnection().setAutoCommit(false);
	}
	
	/**
	 * 事务提交
	 */
	public static void commitAndClose() {
		try {
			// 获取连接
			Connection conn = getConnection();
			// 提交事务
			conn.commit();
			// 释放资源
			conn.close();
			// 解除绑定
			tl.remove();
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}
	
	public static void rollbackAndClose() {
		try {
			// 获取连接
			Connection conn = getConnection();
			// 事务回滚
			conn.rollback();
			// 释放资源
			conn.close();
			// 解除绑定
			tl.remove();
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}
}

2.c3p0-config配置文件

<c3p0-config>
	<!-- 默认配置，如果没有指定则使用这个配置 -->
	<default-config>
		<!-- 基本配置 -->
		<property name="driverClass">com.mysql.jdbc.Driver</property>
		<property name="jdbcUrl">jdbc:mysql://localhost:3306/ajax</property>
		<property name="user">root</property>
		<property name="password">123456</property>
	
		<!--扩展配置-->
		<property name="checkoutTimeout">30000</property>
		<property name="idleConnectionTestPeriod">30</property>
		<property name="initialPoolSize">10</property>
		<property name="maxIdleTime">30</property>
		<property name="maxPoolSize">100</property>
		<property name="minPoolSize">10</property>
		<property name="maxStatements">200</property>
	</default-config> 
</c3p0-config>
posted @ 2018-12-10 17:20  容一博  阅读(3399)  评论(0)  编辑  收藏  举报
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