JavaWeb学习笔记6——JDBC连接MySql进行增删改查并分页显示

数据库的增、删、改、查是非常重要的操作，只要程序是关于数据库的操作，无论程序大小，归根结底都是这4种操作的使用。

连接MySql数据库的过程：

1、注册驱动

DriverManager.registerDriver(new com.mysql.jdbc.Driver());

2、获取数据库连接

Connection conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/数据库名?useUnicode=true&characterEncoding=UTF-8","数据库账号","数据库密码");

3、获取Statement

Statement stmt = conn.createStatement();

4、返回Resultset

ResultSet rs = stmt.executeQuery(sql);

下面的例子就是对MySql数据库进行连接并对tb_person表进行增、删、改、查。

本例子数据库名：databaseWeb，表名：tb_person

                                                                                listPagedPerson.jsp

<%@page import="org.apache.jasper.tagplugins.jstl.core.Param"%>
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"
	contentType="text/html;charset=UTF-8"%>
<%@ page import="java.sql.Connection"%>
<%@ page import="java.sql.ResultSet"%>
<%@ page import="java.sql.Statement"%>
<%@ page import="java.sql.DriverManager"%>
<jsp:directive.page import="java.sql.Date" />
<jsp:directive.page import="java.sql.Timestamp" />
<jsp:directive.page import="java.sql.SQLException" />
<jsp:directive.page import="java.sql.PreparedStatement" />
<jsp:directive.page import="com.hedong.learn.Pagination" />

<style>a{text-decoration:none}</style>  <%--去掉页面超链接的注释 --%>

<form action="listPagedPerson.jsp" method=get>
<input type="hidden" name="action" value="search"> <%--执行查询操作 --%>
	<table align="center">
		<tr>
		    <td>姓名</td>
			<td><input type="text" name='name' value="${param.name}" ></td>
			<td><input type="submit" value="查询"></td>
		</tr>
	</table>
</form>



<%
	final int pageSize = 5;  //每页10条数据
	int pageNum = 1;          //当前页数，默认从第一页开始
	int pageCount = 1;        //总页数
	int recordCount = 0;      //总共有多少条记录
	String action=request.getParameter("action");

	try {
		pageNum = Integer.parseInt(request.getParameter("pageNum"));//取当前页数
	} catch (Exception e) {
	}

	String sql = null;
	Connection conn = null;
	Statement stmt = null;
	ResultSet rs = null;

	try {
		if(!"search".equals(action))
		{
			
			conn=Pagination.getConnection();			
			stmt = conn.createStatement();
			sql = "SELECT count(*) FROM tb_person ";  //查询记录总数的sql语句
			rs = stmt.executeQuery(sql);
			if (rs.next()) {
				recordCount = rs.getInt(1);//获得记录总数
			}
			
			pageCount = (recordCount + pageSize - 1) / pageSize;//计算总页数
			int startRecord = (pageNum - 1) * pageSize;         //计算本页记录从stratRecord开始

			sql = "Select * from tb_person LIMIT "+startRecord+","+pageSize;//此sql语句将记录进行分页			
			rs = stmt.executeQuery(sql);
		}
		else if("search".equals(action))
		{
			String name=request.getParameter("name");//获得要查询的人的名字			
			conn=Pagination.getConnection();
			sql="SELECT * FROM tb_person WHERE name='"+name+"'";
			stmt = conn.createStatement();
			rs = stmt.executeQuery(sql);		
		}
		
%>
<form action="operatePerson.jsp" method=get>
	<table bgcolor="#CCCCCC" cellspacing=1 cellpadding=5 width=100%>
		<tr bgcolor=#DDDDDD>
			<th>序号</th>
			<th>姓名</th>
			<th>英文名</th>
			<th>性别</th>
			<th>年龄</th>
			<th>生日</th>
			<th>备注</th>
			<th>操作</th>
		</tr>
		<%
		    int count=1;
			while (rs.next()) {
			        //获得表中各数据
					int id = rs.getInt("id");
					int age = rs.getInt("age");
					String name = rs.getString("name");
					String englishName = rs.getString("english_name");
					String sex = rs.getString("sex");
					String description = rs.getString("description");
					Date birthday = rs.getDate("birthday");
					//将数据进行写出
					out.println("<tr bgcolor=#FFFFFF>");
					out.println("<td>" + count + "</td>");
					out.println("<td>" + name + "</td>");
					out.println("<td>" + englishName + "</td>");
					out.println("<td>" + sex + "</td>");
					out.println("<td>" + age + "</td>");
					out.println("<td>" + birthday + "</td>");
					out.println("<td>" + description + "</td>");
					out.println("<td>");
					out.println("<a href='operatePerson.jsp?action=del&id=" + id
							+ "' onclick='return confirm(\"确定删除记录？\");'>删除</a>");
					out.println("<a href='operatePerson.jsp?action=edit&id=" + id + "'>修改</a>");
					out.println("</td");
					out.println("</tr>");
					count++;
				}			
		%>
		<tr>
			<td colspan="2" align="left"><a href="addPerson.jsp">新建人员资料</a> <!-- 转到添加人员的页面 --></td>
			<td colspan="6" align="right"><%=Pagination.getPagination(pageNum, pageCount, recordCount, request.getRequestURI())%></td>
		</tr>
	</table>
</form>

<%
	} catch (SQLException e) {
		out.println("执行SQL：" + sql + "时发生异常:" + e.getMessage());
		e.printStackTrace();
	} finally {
		if (rs != null)
			rs.close();
		if (stmt != null)
			stmt.close();
		if (conn != null)
			conn.close();
	}
%>
</body>
</html>

                                                                                    addPerson.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"
	contentType="text/html;charset=UTF-8"%>
<%
	String path = request.getContextPath();
	String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()
			+ path + "/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<%
	String action = (String) request.getAttribute("action");
	String id = (String) request.getAttribute("id");
	String name = (String) request.getAttribute("name");
	String englishName = (String) request.getAttribute("englishName");
	String age = (String) request.getAttribute("age");
	String sex = (String) request.getAttribute("sex");
	String birthday = (String) request.getAttribute("birthday");
	String description = (String) request.getAttribute("description");

	boolean isEdit = "edit".equals(action);//判断是修改还是添加操作
%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
<title><%=isEdit ? "修改人员资料" : "新建人员资料"%></title>
<style type="text/css">
body, td {
	font-size: 12px;
}
</style>
</head>
<body>
	<script type="text/javascript" src="js/calendar.js"></script>
	<!-- 日期日历控件 -->
	<form action="operatePerson.jsp" method="post">
		<input type="hidden" name="action" value="<%=isEdit ? "save" : "add"%>">
		<input type="hidden" name="id" value="<%=isEdit ? id : ""%>">
		<fieldset>
			<legend><%=isEdit ? "修改人员资料" : "新建人员资料"%></legend>
			<table align=center>
				<tr>
					<td>姓名</td>
					<td><input type="text" name="name" value="<%=isEdit ? name : ""%>" /></td>
				</tr>
				<tr>
					<td>英文名</td>
					<td><input type="text" name="englishName" value="<%=isEdit ? englishName : ""%>" /></td>
				</tr>
				<tr>
					<td>性别</td>
					<td><input type="radio" name="sex" value="男" id="sex_male"
							<%=isEdit && "男".equals(sex) ? "checked" : ""%> />
						<label for="sex_male">男</label> 
						<input type="radio" name="sex" value="女" id="sex_female"
							<%=isEdit && "女".equals(sex) ? "checked" : ""%> />
						<label for="sex_female">女</label></td>
				</tr>
				<tr>
					<td>年龄</td>
					<td><input type="text" name="age" value="<%=isEdit ? age : ""%>" /></td>
				</tr>
				<tr>
					<td>生日</td>
					<td><input type="text" name="birthday" onfocus="setday(birthday)"
							value="<%=isEdit ? birthday : ""%>" /><img src="images/calendar.gif"
						onclick="setday(birthday);" /></td>
				</tr>
				<tr>
					<td>描述</td>
					<td><textarea name="description"><%=isEdit ? description : ""%></textarea></td>
				</tr>
				<tr>
					<td></td>
					<td><input type="submit" value="<%=isEdit ? "保存":"添加人员信息" %>" /></td>
				</tr>
			</table>
		</fieldset>
	</form>
</body>
</html>

                                                                              operatePerson.jsp

<%@page import="java.text.SimpleDateFormat"%>
<%@page import="java.sql.PreparedStatement"%>
<%@page import="java.sql.ResultSet"%>
<%@page import="java.sql.SQLException"%>
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"
	contentType="text/html;charset=UTF-8"%>
<%@ page import="java.sql.DriverManager"%>
<%@ page import="java.sql.Connection"%>
<%@ page import="java.sql.Statement"%>
<%@ page import="java.sql.Date"%>
<%@ page import="com.hedong.learn.Pagination" %>

<%
    //获取各种数据
	request.setCharacterEncoding("UTF-8");
	String name = request.getParameter("name");
	String englishName = request.getParameter("englishName");
	String age = request.getParameter("age");
	String birthday = request.getParameter("birthday");
	String sex = request.getParameter("sex");
	String description = request.getParameter("description");
	String action = request.getParameter("action");
    //如果是添加操作
	if ("add".equals(action)) {
		Connection conn = null;
		Statement stmt = null;
		int result = 0;
		
		String sql = "INSERT INTO tb_person(name,english_name,age,sex,birthday,description)" + "values('" + name
				+ "','" + englishName + "','" + age + "','" + sex + "','" + birthday + "','" + description
				+ "')";

		try {
			conn=Pagination.getConnection();
			stmt = conn.createStatement();
			result = stmt.executeUpdate(sql);

		} catch (SQLException e) {
			out.println("执行SQL\"" + sql + "\"时发生异常：" + e.getMessage());
			return;

		} finally {

			if (stmt != null)
				stmt.close();
			if (conn != null)
				conn.close();
		}

		out.println("<html><style>body{font-size:12px;line-height:25px;}</style><body>");
		out.println(result + "条记录被添加到数据库中。");
		out.println("<a href='listPagedPerson.jsp'>返回人员列表</a>");
		out.println("<br/><br/>执行的SQL语句为：<br/>" + sql);
		return;
	}
    //如果是删除操作
	else if ("del".equals(action)) {
		String id=request.getParameter("id");
		String sql="delete from tb_person where id="+id;

		Connection conn = null;
		Statement stmt = null;
		try {
			conn=Pagination.getConnection();
			stmt = conn.createStatement();
			int result = stmt.executeUpdate(sql);

			out.println("<html><style>body{font-size:12px;line-height:25px;}</style><body>");
			out.println(result + "条记录被删除。");
			out.println("<a href='listPagedPerson.jsp'>返回人员列表</a>");
			out.println("<br/><br/>执行的SQL语句为：<br/>" + sql);

		} catch (SQLException e1) {
			out.println("执行SQL\"" + sql + "\"时发生异常：" + e1.getMessage());
		} finally {
			if (stmt != null)
				stmt.close();
			if (conn != null)
				conn.close();
		}

	}
    //如果是修改
	else if ("edit".equals(action)) {
		String id = request.getParameter("id");
		String sql = "SELECT * FROM tb_person WHERE id =" + id;

		Connection conn = null;
		Statement stmt = null;
		ResultSet rs = null;

		try {
			conn=Pagination.getConnection();
			stmt = conn.createStatement();
			rs = stmt.executeQuery(sql);

			if (rs.next()) {
				request.setAttribute("id", rs.getString("id"));
				request.setAttribute("name", rs.getString("name"));
				request.setAttribute("englishName", rs.getString("english_name"));
				request.setAttribute("age", rs.getString("age"));
				request.setAttribute("sex", rs.getString("sex"));
				request.setAttribute("birthday", rs.getString("birthday"));
				request.setAttribute("description", rs.getString("description"));
				request.setAttribute("action", action);

				request.getRequestDispatcher("/addPerson.jsp").forward(request, response);

			} else {
				out.println("没有找到id为" + id + "的记录。");
			}

		} catch (SQLException e2) {
			out.println("执行SQL\"" + sql + "\"时发生异常：" + e2.getMessage());
			e2.printStackTrace();
		} finally {
			if (rs != null)
				rs.close();
			if (stmt != null)
				stmt.close();
			if (conn != null)
				conn.close();
		}

	} 
	//如果是保存操作
	else if ("save".equals(action)) {
		String id = request.getParameter("id");
		String sql = "UPDATE tb_person SET name=?,english_name=?,sex=?,age=?,birthday=?,description=? WHERE id=?";

		Connection conn = null;
		//用PreparedStatement，sql中可含有参数
		PreparedStatement preStmt = null;  

		try {
			conn=Pagination.getConnection();

			SimpleDateFormat f = new SimpleDateFormat("yyyy-MM-dd");
			Date d = new Date(f.parse(birthday).getTime());

			preStmt = conn.prepareStatement(sql);
			preStmt.setString(1, name);
			preStmt.setString(2, englishName);
			preStmt.setString(3, sex);
			preStmt.setInt(4, Integer.parseInt(age));
			preStmt.setDate(5, d);
			preStmt.setString(6, description);
			preStmt.setInt(7, Integer.parseInt(id));

			int result = preStmt.executeUpdate();//此时括号中无需填写sql

			out.println("<html><style>body{font-size:12px;line-height:25px;}</style><body>");

			if (result == 0)
				out.println("影响数目为0，修改失败。");
			else
				out.println(result + "条记录被修改。");

			out.println("<a href='listPagedPerson.jsp'>返回人员列表</a>");
			out.println("<br/><br/>执行的SQL语句为：<br/>" + sql);

		} catch (SQLException e3) {
			out.println("执行SQL\"" + sql + "\"时发生异常：" + e3.getMessage());
			e3.printStackTrace();
		} finally {
			if (preStmt != null)
				preStmt.close();
			if (conn != null)
				conn.close();
		}
	}
%>

下面是运行后的结果