今天给大家介绍一种新的数据连接池实现方式——proxool数据库连接池，这是一个健壮、易用的连接池。以下通过一个Demo说明一下怎样使用：
项目结构例如以下：
DBLink.java文件里的代码：
package com.ghj.util; import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map; public class DBLink { private Connection connection;
private PreparedStatement preparedStatement;
private ResultSet resultSet; static{
try {
Class.forName("org.logicalcobwebs.proxool.ProxoolDriver"); //载入驱动
}catch (ClassNotFoundException e) {
System.out.println("载入驱动失败！");
e.printStackTrace();
}
} private Connection getConn(){
try {
if(connection==null||connection.isClosed()){
connection = DriverManager.getConnection("proxool.mysqlsource"); //获取连接
}
} catch (SQLException e) {
System.out.println("获取连接失败。");
e.printStackTrace();
}
return connection;
} public List<Map<String, Object>> select(String sql, Object [] params){
List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
try{
connection = this.getConn();
preparedStatement = connection.prepareStatement(sql);
if(params != null){
for(int i =0; i<params.length; i++){
preparedStatement.setObject(i+1, params[i]);//逐一给问号赋值
}
}
resultSet = preparedStatement.executeQuery();
ResultSetMetaData rsmd = resultSet.getMetaData();
int columnCount = rsmd.getColumnCount();
while(resultSet.next()){
Map<String, Object> map = new HashMap<String, Object>();
for(int i =1; i<=columnCount;i++){
String columnName = rsmd.getColumnName(i);
Object obj = null;
if(rsmd.getColumnTypeName(i).equals("DATE")){
obj = resultSet.getString(columnName);
}else{
obj = resultSet.getObject(columnName);
}
map.put(columnName, obj);
}
list.add(map);
}
}catch(SQLException e){
e.printStackTrace();
}finally{
close();
}
return list;
} private void close(){
try {
if(resultSet != null){
resultSet.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
try {
if(preparedStatement != null){
preparedStatement.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
try {
connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
proxool.xml文件里的代码：
<?xml version="1.0" encoding="UTF-8"?>
<proxool-config>
<proxool>
<alias>mysqlsource</alias>
<driver-url>jdbc:mysql://localhost:3306/test</driver-url>
<driver-class>com.mysql.jdbc.Driver</driver-class>
<driver-properties>
<property name="user" value="root" />
<property name="password" value="root" />
</driver-properties>
<!-- 保留线程处于睡眠状态的最长时间 -->
<house-keeping-sleep-time>60000</house-keeping-sleep-time>
<maximum-connection-count>30</maximum-connection-count>
<minimum-connection-count>10</minimum-connection-count>
<!-- 连接池中可用的连接数量（空暇状态） -->
<prototype-count>5</prototype-count>
<maximum-new-connections>1</maximum-new-connections>
<simultaneous-build-throttle>1</simultaneous-build-throttle>
<!-- 连接池使用状态 -->
<statistics>30s,10m,1d</statistics>
<!-- 连接池日志类型 -->
<statistics-log-level>ERROR</statistics-log-level>
<!-- 假设为true,那么每一个被运行的SQL语句将会在运行期被log记录(DEBUG LEVEL) -->
<trace>true</trace> <house-keeping-test-sql>select CURRENT_DATE</house-keeping-test-sql>
</proxool>
</proxool-config>
web.xml文件里的代码：
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"> <!-- 连接池 -->
<servlet>
<servlet-name>ServletConfigurator</servlet-name>
<servlet-class>org.logicalcobwebs.proxool.configuration.ServletConfigurator</servlet-class>
<init-param>
<param-name>xmlFile</param-name>
<param-value>WEB-INF/proxool.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet> <welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
index.jsp文件里的代码：
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@page import="com.ghj.util.DBLink,java.util.List,java.util.Map"%> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>首页</title>
</head> <body>
<table width="100%" border="1px">
<tr>
<th>序号 </th><th>班级名称</th><th>开班日期</th><th>结束日期</th><th>状态</th><th>操作</th>
</tr>
<%
String sql = "SELECT id, class_name, begin_date, end_date, state FROM class ";
DBLink db = new DBLink();
List<Map<String, Object>> list = db.select(sql, null);
int index = 0;
for (Map<String, Object> map : list) {
index = index + 1;
int id = Integer.parseInt(map.get("id").toString());
String className = map.get("class_name").toString();
String beginDate = map.get("begin_date").toString();
String endDate = map.get("end_date").toString();
int state = Integer.parseInt(map.get("state").toString());
String stateName = (state == 0 ? "未启用" : "启用");
%>
<tr align="center">
<td><%=index%></td><td><%=className%></td><td><%=beginDate%></td><td><%=endDate%></td><td><%=stateName%></td><td>【<a href="###" onclick="">改动</a>】【<a href="###" onclick="">查看</a>】【<a href="###" onclick="">删除</a>】</td>
</tr>
<%
}
%>
</table>
</body>
</html>
【0分下载演示样例】