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Tomcat5.0-5.5连接池配置指南
摘要: 在实际应用开发中，特别是在WEB应用系统中，如果JSP、Servlet或EJB使用JDBC直接访问数据库中的数据，每一次数据访问请求都必须经历建立数据库连接、打开数据库、存取数据和关闭数据库连接等步骤，而连接并打开数据库是一件既消耗资源又费时的工作，如果频繁发生这种数据库操作，系统的性能必然会急剧下降，甚至会导致系统崩溃。数据库连接池技术是解决这个问题最常用的方法.
在进行Tomcat连接池配置前，先解压缩mysql-connector-java-xxx.zip，将其中的mysql-connector-java-3.x.x-xxx.jar取出，置于<%TOMCAT_HOME%>\common\lib中。
接下来，让我们一起进入精彩的Tomcat配置之旅。
一.新建用户及数据库
操作步骤如下：
C:\Documents and Settings\Administrator>d:
D:\>cd mysql\bin
D:\MySQL\bin>mysql -u root -p
Enter password: *******
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 51 to server version: 4.1.12a-nt
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
mysql> GRANT ALL PRIVILEGES ON jcc.* TO jcc@localhost IDENTIFIED BY 'jsp.com.cn'
WITH GRANT OPTION;
Query OK, 0 rows affected (0.01 sec)
mysql> USE mysql;
Database changed
mysql> SELECT Host,User,Password FROM user;
+-----------+------+-------------------------------------------+
| Host | User | Password |
+-----------+------+-------------------------------------------+
| localhost | root | *60D5B730382EC2170CA366DE181767E4C5343DE8 |
| % | jsp | *C22AB0FD8A289C7D337C9998B63B8EA8335E5F35 |
| localhost | jcc | *C22AB0FD8A289C7D337C9998B63B8EA8335E5F35 |
+-----------+------+-------------------------------------------+
3 rows in set (0.01 sec)
mysql> exit
Bye
D:\MySQL\bin>mysql -u jcc -p
Enter password: **********
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 57 to server version: 4.1.12a-nt
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
mysql> CREATE DATABASE jcc;
Query OK, 1 row affected (0.02 sec)
mysql> USE jcc;
Database changed
mysql> CREATE TABLE user(
-> id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
-> name VARCHAR(8) NOT NULL
-> );
Query OK, 0 rows affected (0.08 sec)
mysql> INSERT INTO user (name) VALUES ('Corebit');
Query OK, 1 row affected (0.03 sec)
mysql> INSERT INTO user (name) VALUES ('Ivan');
Query OK, 1 row affected (0.03 sec)
mysql> SELECT * FROM user;
+----+---------+
| id | name |
+----+---------+
| 1 | Corebit |
| 2 | Ivan |
+----+---------+
2 rows in set (0.00 sec)
mysql>
二.配置Tomcat连接池
Tomcat5.0进行如下配置：
在<%TOMCAT_HOME%>\conf\server.xml的
debug="5" reloadable="true" crossContext="true">
prefix="localhost_DBTest_log." suffix=".txt"
timestamp="true"/>
auth="Container"
type="javax.sql.DataSource"/>
factory
org.apache.commons.dbcp.BasicDataSourceFactory
maxActive
100
maxIdle
30
maxWait
10000
username
jcc
password
jsp.com.cn
driverClassName
com.mysql.jdbc.Driver
url
jdbc:mysql://localhost/jcc
Tomcat5.5进行如下配置：
在<%TOMCAT_HOME%>\conf\server.xml的
<
Context path="" docBase="D:/jcc"
debug="5" reloadable="true" crossContext="true">
maxActive="100" maxIdle="30" maxWait="10000"
username="jcc" password="jsp.com.cn" driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost/jcc"/>
三.在<%wwwroot%>/下，新建MySQL数据库连接文件Select.jsp
Select.jsp源码如下：
<%@page contentType="text/html;charset=gb2312"%>
<%@page import="java.sql.*"%>
<%@page import="javax.sql.DataSource"%>
<%@page import="javax.naming.*"%>
<body>
<%
try{
Context initCtx=new InitialContext();
DataSource db = (DataSource)initCtx.lookup("java:comp/env/jdbc/JCC");
Connection conn = db.getConnection();
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery("SELECT * FROM user");
out.println("User-list"+"
");
while(rs.next()){
out.print(rs.getString(1)+" ");
out.print(rs.getString(2)+"
");
}
rs.close();
stmt.close();
conn.close();
}
catch(Exception e){
out.print(e);
}
%>
</body>
四.运行http://localhost/Select.jsp，显示结果如下：
User-list
1 Corebit
2 Ivan
则表示数据库连接成功！恭喜！恭喜！
否则请检查数据库连接器版本，出错可能性比较高！
＊注：
Tomcat连接池中，部分参数说明如下：
maxActive="100"