MySQL DBCP Example
0. Introduction
Versions of MySQL and JDBC drivers that have been reported to work: MySQL 3.23.47, MySQL 3.23.47 using InnoDB,, MySQL 3.23.58, MySQL 4.0.1alpha
Connector/J 3.0.11-stable (the official JDBC Driver)
mm.mysql 2.0.14 (an old 3rd party JDBC Driver) Before you proceed, don't forget to copy the JDBC Driver's jar into $CATALINA_HOME/common/lib.1. MySQL configuration
Ensure that you follow these instructions as variations can cause problems. Create a new test user, a new database and a single test table. Your MySQL user must have a password assigned. The driver will fail if you try to connect with an empty password.
mysql> GRANT ALL PRIVILEGES ON *.* TO javauser@localhost
-> IDENTIFIED BY 'javadude' WITH GRANT OPTION;
mysql> create database javatest;
mysql> use javatest;
mysql> create table testdata (
-> id int not null auto_increment primary key,
-> foo varchar(25),
-> bar int);
Note: the above user should be removed once testing is complete! Next insert some test data into the testdata table.
mysql> insert into testdata values(null, 'hello', 12345);
Query OK, 1 row affected (0.00 sec)mysql> select * from testdata;
+----+-------+-------+
| ID | FOO | BAR |
+----+-------+-------+
| 1 | hello | 12345 |
+----+-------+-------+
1 row in set (0.00 sec)mysql>
2. server.xml configuration
Configure the JNDI DataSource in Tomcat by adding a declaration for your resource to $CATALINA_HOME/conf/server.xml.Add this in between the </Context> tag of the examples context and the </Host> tag closing the localhost definition.
<Context path="/DBTest" docBase="DBTest"
debug="5" reloadable="true" crossContext="true"> <Logger className="org.apache.catalina.logger.FileLogger"
prefix="localhost_DBTest_log." suffix=".txt"
timestamp="true"/> <Resource name="jdbc/TestDB"
auth="Container"
type="javax.sql.DataSource"/> <ResourceParams name="jdbc/TestDB">
<parameter>
<name>factory</name>
<value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
</parameter> <!-- Maximum number of dB connections in pool. Make sure you
configure your mysqld max_connections large enough to handle
all of your db connections. Set to 0 for no limit.
-->
<parameter>
<name>maxActive</name>
<value>100</value>
</parameter> <!-- Maximum number of idle dB connections to retain in pool.
Set to 0 for no limit.
-->
<parameter>
<name>maxIdle</name>
<value>30</value>
</parameter> <!-- Maximum time to wait for a dB connection to become available
in ms, in this example 10 seconds. An Exception is thrown if
this timeout is exceeded. Set to -1 to wait indefinitely.
-->
<parameter>
<name>maxWait</name>
<value>10000</value>
</parameter> <!-- MySQL dB username and password for dB connections -->
<parameter>
<name>username</name>
<value>javauser</value>
</parameter>
<parameter>
<name>password</name>
<value>javadude</value>
</parameter> <!-- Class name for the old mm.mysql JDBC driver - uncomment this entry and comment next
if you want to use this driver - we recommend using Connector/J though
<parameter>
<name>driverClassName</name>
<value>org.gjt.mm.mysql.Driver</value>
</parameter>
-->
<!-- Class name for the official MySQL Connector/J driver -->
<parameter>
<name>driverClassName</name>
<value>com.mysql.jdbc.Driver</value>
</parameter>
<!-- The JDBC connection url for connecting to your MySQL dB.
The autoReconnect=true argument to the url makes sure that the
mm.mysql JDBC Driver will automatically reconnect if mysqld closed the
connection. mysqld by default closes idle connections after 8 hours.
-->
<parameter>
<name>url</name>
<value>jdbc:mysql://localhost:3306/javatest?autoReconnect=true</value>
</parameter>
</ResourceParams>
</Context>
3. web.xml configuration
Now create a WEB-INF/web.xml for this test application.
<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
version="2.4">
<web-app>
<description>MySQL Test App</description>
<resource-ref>
<description>DB Connection</description>
<res-ref-name>jdbc/TestDB</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
</web-app>
4. Test code
Now create a simple test.jsp page for use later.
<%@ taglib uri="http://java.sun.com/jsp/jstl/sql" prefix="sql" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %><sql:query var="rs" dataSource="jdbc/TestDB">
select id, foo, bar from testdata
</sql:query><html>
<head>
<title>DB Test</title>
</head>
<body> <h2>Results</h2>
<c:forEach var="row" items="${rs.rows}">
Foo ${row.foo}<br/>
Bar ${row.bar}<br/>
</c:forEach> </body>
</html>
That JSP page makes use of JSTL's SQL and Core taglibs. You can get it from Sun's Java Web Services Developer Pack or Jakarta Taglib Standard 1.1 project - just make sure you get a 1.1.x release. Once you have JSTL, copy jstl.jar and standard.jar to your web app's WEB-INF/lib directory. Finally deploy your web app into $CATALINA_HOME/webapps either as a warfile called DBTest.war or into a sub-directory called DBTestOnce deployed, point a browser at http://localhost:8080/DBTest/test.jsp to view the fruits of your hard work.
0. Introduction
Versions of MySQL and JDBC drivers that have been reported to work: MySQL 3.23.47, MySQL 3.23.47 using InnoDB,, MySQL 3.23.58, MySQL 4.0.1alpha
Connector/J 3.0.11-stable (the official JDBC Driver)
mm.mysql 2.0.14 (an old 3rd party JDBC Driver) Before you proceed, don't forget to copy the JDBC Driver's jar into $CATALINA_HOME/common/lib.1. MySQL configuration
Ensure that you follow these instructions as variations can cause problems. Create a new test user, a new database and a single test table. Your MySQL user must have a password assigned. The driver will fail if you try to connect with an empty password.
mysql> GRANT ALL PRIVILEGES ON *.* TO javauser@localhost
-> IDENTIFIED BY 'javadude' WITH GRANT OPTION;
mysql> create database javatest;
mysql> use javatest;
mysql> create table testdata (
-> id int not null auto_increment primary key,
-> foo varchar(25),
-> bar int);
Note: the above user should be removed once testing is complete! Next insert some test data into the testdata table.
mysql> insert into testdata values(null, 'hello', 12345);
Query OK, 1 row affected (0.00 sec)mysql> select * from testdata;
+----+-------+-------+
| ID | FOO | BAR |
+----+-------+-------+
| 1 | hello | 12345 |
+----+-------+-------+
1 row in set (0.00 sec)mysql>
2. server.xml configuration
Configure the JNDI DataSource in Tomcat by adding a declaration for your resource to $CATALINA_HOME/conf/server.xml.Add this in between the </Context> tag of the examples context and the </Host> tag closing the localhost definition.
<Context path="/DBTest" docBase="DBTest"
debug="5" reloadable="true" crossContext="true"> <Logger className="org.apache.catalina.logger.FileLogger"
prefix="localhost_DBTest_log." suffix=".txt"
timestamp="true"/> <Resource name="jdbc/TestDB"
auth="Container"
type="javax.sql.DataSource"/> <ResourceParams name="jdbc/TestDB">
<parameter>
<name>factory</name>
<value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
</parameter> <!-- Maximum number of dB connections in pool. Make sure you
configure your mysqld max_connections large enough to handle
all of your db connections. Set to 0 for no limit.
-->
<parameter>
<name>maxActive</name>
<value>100</value>
</parameter> <!-- Maximum number of idle dB connections to retain in pool.
Set to 0 for no limit.
-->
<parameter>
<name>maxIdle</name>
<value>30</value>
</parameter> <!-- Maximum time to wait for a dB connection to become available
in ms, in this example 10 seconds. An Exception is thrown if
this timeout is exceeded. Set to -1 to wait indefinitely.
-->
<parameter>
<name>maxWait</name>
<value>10000</value>
</parameter> <!-- MySQL dB username and password for dB connections -->
<parameter>
<name>username</name>
<value>javauser</value>
</parameter>
<parameter>
<name>password</name>
<value>javadude</value>
</parameter> <!-- Class name for the old mm.mysql JDBC driver - uncomment this entry and comment next
if you want to use this driver - we recommend using Connector/J though
<parameter>
<name>driverClassName</name>
<value>org.gjt.mm.mysql.Driver</value>
</parameter>
-->
<!-- Class name for the official MySQL Connector/J driver -->
<parameter>
<name>driverClassName</name>
<value>com.mysql.jdbc.Driver</value>
</parameter>
<!-- The JDBC connection url for connecting to your MySQL dB.
The autoReconnect=true argument to the url makes sure that the
mm.mysql JDBC Driver will automatically reconnect if mysqld closed the
connection. mysqld by default closes idle connections after 8 hours.
-->
<parameter>
<name>url</name>
<value>jdbc:mysql://localhost:3306/javatest?autoReconnect=true</value>
</parameter>
</ResourceParams>
</Context>
3. web.xml configuration
Now create a WEB-INF/web.xml for this test application.
<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
version="2.4">
<web-app>
<description>MySQL Test App</description>
<resource-ref>
<description>DB Connection</description>
<res-ref-name>jdbc/TestDB</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
</web-app>
4. Test code
Now create a simple test.jsp page for use later.
<%@ taglib uri="http://java.sun.com/jsp/jstl/sql" prefix="sql" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %><sql:query var="rs" dataSource="jdbc/TestDB">
select id, foo, bar from testdata
</sql:query><html>
<head>
<title>DB Test</title>
</head>
<body> <h2>Results</h2>
<c:forEach var="row" items="${rs.rows}">
Foo ${row.foo}<br/>
Bar ${row.bar}<br/>
</c:forEach> </body>
</html>
That JSP page makes use of JSTL's SQL and Core taglibs. You can get it from Sun's Java Web Services Developer Pack or Jakarta Taglib Standard 1.1 project - just make sure you get a 1.1.x release. Once you have JSTL, copy jstl.jar and standard.jar to your web app's WEB-INF/lib directory. Finally deploy your web app into $CATALINA_HOME/webapps either as a warfile called DBTest.war or into a sub-directory called DBTestOnce deployed, point a browser at http://localhost:8080/DBTest/test.jsp to view the fruits of your hard work.
解决方案 »
- Lost connection to MySQL server at 'reading initial communication packet', syste
- Mysql存储过程怎么跳出死循环While语句的方法。
- 这样的SQL语句怎么写啊,内详。。。
- 如何实现远程登陆
- 按用户加入时间,获取第50000名加入用户,和他前后的10名用户发奖励。怎样快速获得要求结果?
- 这个表应该怎么设计 ?
- 请问唯一约束怎那么应用到两个字段的组合之上
- 关于半角单引号如何写入数据库的问题,困扰了我很久,如能解决,高分相赠
- mysql和VB问题
- win7环境下mysql5卸载后服务安装不上
- mysql怎么建数据库阿?
- Java处理数据库的事务疑问,麻烦大家:)
请问如何修改默认的用户和密码,才能使我能够正确的通过jsp页面连接上数据库!
为表感谢!!
Class.forName("org.gjt.mm.mysql.Driver").newInstance();
Connection con=java.sql.DriverManager.getConnection("jdbc:mysql://127.0.0.1/test","root","");
Statement stmt=con.createStatement();
ResultSet rst=stmt.executeQuery("select * from book:");
-----------
你的错误在于加载驱动程序的错误。
改成这样:
Class.forName("com.mysql.jdbc.Driver").newInstance();
其它的不用改了。试试先。