Spring数据源的灵活配置巧应用
环境:
Java SE 1.5
Spring-2.5.1
mysql-connector-java-5.1.5.zip
Mysql 5.x
Java SE 1.5
Spring-2.5.1
mysql-connector-java-5.1.5.zip
Mysql 5.x
为了从数据库中取得数据,我们首先需要获取一个数据库连接。 Spring通过DataSource对象来完成这个工作。 DataSource是JDBC规范的一部分, 它被视为一个通用的数据库连接工厂。通过使用DataSource, Container或Framework可以将连接池以及事务管理的细节从应用代码中分离出来。 作为一个开发人员,在开发和测试产品的过程中,你可能需要知道连接数据库的细节。 但在产品实施时,你不需要知道这些细节。通常数据库管理员会帮你设置好数据源。
在使用Spring JDBC时,你既可以通过JNDI获得数据源,也可以自行配置数据源( 使用Spring提供的DataSource实现类)。使用后者可以更方便的脱离Web容器来进行单元测试。 这里我们将使用DriverManagerDataSource,不过DataSource有多种实现, 后面我们会讲到。使用DriverManagerDataSource和你以前获取一个JDBC连接 的做法没什么两样。你首先必须指定JDBC驱动程序的全限定名,这样DriverManager 才能加载JDBC驱动类,接着你必须提供一个url(因JDBC驱动而异,为了保证设置正确请参考相关JDBC驱动的文档), 最后你必须提供一个用户连接数据库的用户名和密码。
以上两段文字摘自Spring开发文档原文,下面我写的一个小的应用,用来测试Srping JDBC支持的效果。
下面这个测试要实现一个目标:通过获取Spring的数据源来查询MySQL数据库testdb的一个表t_user数据。
一、创建项目,加载程序用到的工具包和驱动。并在源代码目录中添加Spring的配置文件ApplicationContext.xml,配置内容如下:
<?
xml
version
="1.0"
encoding
="gb2312"
?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
< beans >
<!-- 数据库的数据源定义-->
< bean id ="rptds" class ="org.springframework.jdbc.datasource.DriverManagerDataSource" destroy-method ="close" >
< property name ="driverClassName" >
< value >com.mysql.jdbc.Driver </ value >
</ property >
< property name ="url" >
< value >jdbc:mysql://localhost:3306/testdb </ value >
</ property >
< property name ="username" >
< value >root </ value >
</ property >
< property name ="password" >
< value >leizhimin </ value >
</ property >
</ bean >
</ beans >
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
< beans >
<!-- 数据库的数据源定义-->
< bean id ="rptds" class ="org.springframework.jdbc.datasource.DriverManagerDataSource" destroy-method ="close" >
< property name ="driverClassName" >
< value >com.mysql.jdbc.Driver </ value >
</ property >
< property name ="url" >
< value >jdbc:mysql://localhost:3306/testdb </ value >
</ property >
< property name ="username" >
< value >root </ value >
</ property >
< property name ="password" >
< value >leizhimin </ value >
</ property >
</ bean >
</ beans >
二、然后创建数据库环境:
create database if not exists testdb;
DROP TABLE IF EXISTS t_user;
CREATE TABLE t_user (
id int(11) NOT NULL auto_increment,
firstname varchar(50) default NULL,
lastname varchar(50) default NULL,
zipcode varchar(10) default NULL,
tel varchar(20) default NULL,
address varchar(200) default NULL,
PRIMARY KEY (id)
) ENGINE=InnoDB DEFAULT CHARSET=gbk;
insert into t_user(id,firstname,lastname,zipcode,tel,address) values
(1,'haha','hehe','234444','13577788999','阿斯地方'),
(2,'lei','aaa','450000','13939012107','郑州市经三路');
DROP TABLE IF EXISTS t_user;
CREATE TABLE t_user (
id int(11) NOT NULL auto_increment,
firstname varchar(50) default NULL,
lastname varchar(50) default NULL,
zipcode varchar(10) default NULL,
tel varchar(20) default NULL,
address varchar(200) default NULL,
PRIMARY KEY (id)
) ENGINE=InnoDB DEFAULT CHARSET=gbk;
insert into t_user(id,firstname,lastname,zipcode,tel,address) values
(1,'haha','hehe','234444','13577788999','阿斯地方'),
(2,'lei','aaa','450000','13939012107','郑州市经三路');
三、Spring Bean容器环境获取工具类
package com.lavasoft.dbtest;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
* Created by IntelliJ IDEA.
* File: ContextHelper.java
* User: leizhimin
* Date: 2008-2-21 14:20:46
* Spring Bean容器环境获取工具类
*/
public final class ContextHelper {
private static ClassPathXmlApplicationContext _ctx;
static {
_ctx = new ClassPathXmlApplicationContext( "ApplicationContext.xml");
}
private ContextHelper() {
}
public static ClassPathXmlApplicationContext getContext() {
return _ctx;
}
}
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
* Created by IntelliJ IDEA.
* File: ContextHelper.java
* User: leizhimin
* Date: 2008-2-21 14:20:46
* Spring Bean容器环境获取工具类
*/
public final class ContextHelper {
private static ClassPathXmlApplicationContext _ctx;
static {
_ctx = new ClassPathXmlApplicationContext( "ApplicationContext.xml");
}
private ContextHelper() {
}
public static ClassPathXmlApplicationContext getContext() {
return _ctx;
}
}
三、写获取数据库工具类
package com.lavasoft.dbtest;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.CallableStatement;
/**
* Created by IntelliJ IDEA.
* File: DBUtil.java
* User: leizhimin
* Date: 2008-2-21 14:26:30
* 数据库工具
*/
public final class DBUtil {
private static final Log log = LogFactory.getLog(DBUtil. class);
/**
* 获取系统的数据源
*
* @return DataSource
*/
public static DataSource getDataSource() {
DataSource dataSource = null;
try {
dataSource = (DataSource) ContextHelper.getContext().getBean( "rptds");
} catch (Exception e) {
log.error( "获取数据源出错,请检查Spring数据源配置!");
}
return dataSource;
}
/**
* 获取数据库连接
*
* @return Connection
*/
public static Connection makeConnection() {
Connection conn = null;
try {
conn = getDataSource().getConnection();
} catch (SQLException e) {
log.error( "通过数据源获取数据库连接发生异常!");
e.printStackTrace();
}
return conn;
}
/**
* 执行没有参数的SQL过程
*
* @param procedureName 存储过程名字
* @return boolean 返回存储过程执行的结果,true表示执行成功,false表示执行失败.
*/
public static boolean executeBSDProcedure(String procedureName) {
boolean flag = false;
String sqlStr = "{call " + procedureName + "()}";
CallableStatement cs;
Connection conn = makeConnection();
try {
cs = (CallableStatement) conn.prepareStatement(sqlStr);
cs.executeUpdate(sqlStr);
flag = true;
} catch (SQLException e) {
log.error( "调用存储过程" + sqlStr + "失败!");
e.printStackTrace();
}
return flag;
}
}
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.CallableStatement;
/**
* Created by IntelliJ IDEA.
* File: DBUtil.java
* User: leizhimin
* Date: 2008-2-21 14:26:30
* 数据库工具
*/
public final class DBUtil {
private static final Log log = LogFactory.getLog(DBUtil. class);
/**
* 获取系统的数据源
*
* @return DataSource
*/
public static DataSource getDataSource() {
DataSource dataSource = null;
try {
dataSource = (DataSource) ContextHelper.getContext().getBean( "rptds");
} catch (Exception e) {
log.error( "获取数据源出错,请检查Spring数据源配置!");
}
return dataSource;
}
/**
* 获取数据库连接
*
* @return Connection
*/
public static Connection makeConnection() {
Connection conn = null;
try {
conn = getDataSource().getConnection();
} catch (SQLException e) {
log.error( "通过数据源获取数据库连接发生异常!");
e.printStackTrace();
}
return conn;
}
/**
* 执行没有参数的SQL过程
*
* @param procedureName 存储过程名字
* @return boolean 返回存储过程执行的结果,true表示执行成功,false表示执行失败.
*/
public static boolean executeBSDProcedure(String procedureName) {
boolean flag = false;
String sqlStr = "{call " + procedureName + "()}";
CallableStatement cs;
Connection conn = makeConnection();
try {
cs = (CallableStatement) conn.prepareStatement(sqlStr);
cs.executeUpdate(sqlStr);
flag = true;
} catch (SQLException e) {
log.error( "调用存储过程" + sqlStr + "失败!");
e.printStackTrace();
}
return flag;
}
}
四、写测试类
package com.lavasoft.dbtest;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import java.sql.Connection;
import java.sql.Statement;
import java.sql.ResultSet;
import java.sql.SQLException;
/**
* Created by IntelliJ IDEA.
* File: Test.java
* User: leizhimin
* Date: 2008-2-21 14:41:49
* Spring 数据源应用测试
*/
public class Test {
private static final Log log = LogFactory.getLog(Test. class);
public static void main(String args[]) {
Test.test();
}
public static void test() {
String testSql = "select * from t_user";
Connection conn = DBUtil.makeConnection();
Statement stmt = null;
try {
stmt = conn.createStatement(ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY, ResultSet.CLOSE_CURSORS_AT_COMMIT);
ResultSet rs = stmt.executeQuery(testSql);
while (rs.next()) {
String firstName = rs.getString( "firstname");
String lastName = rs.getString( "lastname");
System.out.println(firstName + " " + lastName);
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
if (stmt != null) {
try {
stmt.close();
} catch (SQLException e) {
log.info( "关闭Statement对象出现异常!");
e.printStackTrace();
}
}
if (conn != null) {
try {
conn.close();
} catch (SQLException e) {
log.error( "关闭数据库连接失败!");
e.printStackTrace();
}
}
}
}
}
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import java.sql.Connection;
import java.sql.Statement;
import java.sql.ResultSet;
import java.sql.SQLException;
/**
* Created by IntelliJ IDEA.
* File: Test.java
* User: leizhimin
* Date: 2008-2-21 14:41:49
* Spring 数据源应用测试
*/
public class Test {
private static final Log log = LogFactory.getLog(Test. class);
public static void main(String args[]) {
Test.test();
}
public static void test() {
String testSql = "select * from t_user";
Connection conn = DBUtil.makeConnection();
Statement stmt = null;
try {
stmt = conn.createStatement(ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY, ResultSet.CLOSE_CURSORS_AT_COMMIT);
ResultSet rs = stmt.executeQuery(testSql);
while (rs.next()) {
String firstName = rs.getString( "firstname");
String lastName = rs.getString( "lastname");
System.out.println(firstName + " " + lastName);
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
if (stmt != null) {
try {
stmt.close();
} catch (SQLException e) {
log.info( "关闭Statement对象出现异常!");
e.printStackTrace();
}
}
if (conn != null) {
try {
conn.close();
} catch (SQLException e) {
log.error( "关闭数据库连接失败!");
e.printStackTrace();
}
}
}
}
}
测试运行结果:
haha hehe
lei aaa
Process finished with exit code 0
lei aaa
Process finished with exit code 0
五、数据源置换
Spring实现的DriverManagerDataSource并没有提供连接池的功能,只是用来作简单的单机连接测试,并不适合使用于真正的项目当中,可以考虑用比较成熟的数据连接池来取代。Apache DBCP连接池是不错,如要要替换,则需要加载DBCP相关的工具包。
<?
xml
version
="1.0"
encoding
="gb2312"
?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
< beans >
<!-- 数据库的数据源定义-->
< bean id ="rptds" class ="org.apache.commons.dbcp.BasicDataSource" destroy-method ="close" >
< property name ="driverClassName" >
< value >com.mysql.jdbc.Driver </ value >
</ property >
< property name ="url" >
< value >jdbc:mysql://localhost:3306/testdb </ value >
</ property >
< property name ="username" >
< value >root </ value >
</ property >
< property name ="password" >
< value >leizhimin </ value >
</ property >
</ bean >
</ beans >
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
< beans >
<!-- 数据库的数据源定义-->
< bean id ="rptds" class ="org.apache.commons.dbcp.BasicDataSource" destroy-method ="close" >
< property name ="driverClassName" >
< value >com.mysql.jdbc.Driver </ value >
</ property >
< property name ="url" >
< value >jdbc:mysql://localhost:3306/testdb </ value >
</ property >
< property name ="username" >
< value >root </ value >
</ property >
< property name ="password" >
< value >leizhimin </ value >
</ property >
</ bean >
</ beans >
现在所使用的是org.apache.commons.dbcp.BasicDataSource作为注入的DataSource实例,为了使用DBCP 的功能,您需要在Classpath路径中设定commons-dbcp.jar、commons-pool.jar与commons- collections.jar。注意到在dataSource上设定了"destroy-method"属性,如此可以确保BeanFactory在关闭时也一并关闭BasicDataSource。
六、使用JNDI数据源
如果您的Servlet容器提供了JNDI(Java Naming and Directory Interface)的DataSource,您也可以简单的换上这个DataSource:
<?
xml
version
="1.0"
encoding
="gb2312"
?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
< beans >
<!-- 数据库的数据源定义-->
< bean id ="dataSource"
class ="org.springframework.indi.JndiObjectFactoryBean" >
< property name ="jndiName" >
< value >jdbc/testds </ value >
</ property >
</ bean >
</ beans >
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
< beans >
<!-- 数据库的数据源定义-->
< bean id ="dataSource"
class ="org.springframework.indi.JndiObjectFactoryBean" >
< property name ="jndiName" >
< value >jdbc/testds </ value >
</ property >
</ bean >
</ beans >
为了使用org.springframework.indi.JndiObjectFactoryBean,您需要spring-context.jar,"jndiName"实际上要根据您所设定的JNDI查询名称。
参考资料:
Spring 2.0开发文档
Spring 技术手册
Spring 2.0开发文档
Spring 技术手册
祝各位元宵节快乐!!!
本文转自 leizhimin 51CTO博客,原文链接:http://blog.51cto.com/lavasoft/62686,如需转载请自行联系原作者