一些开源组织提供了数据源的独立实现：
DBCP数据库连接池
C3P0数据库连接池
Apache Tomcat内置的连接池
DBCP连接池
apache提供的连接池实现，需要导入common-dbcp.jar commons-pool.jar
import java.io.FileReader;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.Properties; import javax.sql.DataSource; import org.apache.commons.dbcp.BasicDataSourceFactory; public class DBCPTest {
public static void main(String[] args) throws Exception {
//导入配置文件
Properties prop=new Properties();
prop.load(new FileReader("dbcp.properties"));
//获取数据源
BasicDataSourceFactory factory=new BasicDataSourceFactory();
DataSource pool=factory.createDataSource(prop); Connection conn=pool.getConnection();
//获取传输器对象
Statement statement=conn.createStatement();
//获取结果集对象
ResultSet resultSet=statement.executeQuery("select * from user");
//遍历
while(resultSet.next()){
String username=resultSet.getString("username");
System.out.println(username);
}
//关闭资源
resultSet.close();
statement.close();
conn.close(); }
}
在项目目录下新建dacp.properties
driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql:///java
username=root
password=root
C3P0连接池
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement; import com.mchange.v2.c3p0.ComboPooledDataSource; public class DBCPTest {
public static void main(String[] args) throws Exception {
//使用C3P0
ComboPooledDataSource pool=new ComboPooledDataSource();
Connection conn=pool.getConnection();
//获取传输器对象
Statement statement=conn.createStatement();
//获取结果集对象
ResultSet resultSet=statement.executeQuery("select * from user");
//遍历
while(resultSet.next()){
String username=resultSet.getString("username");
System.out.println(username);
}
//关闭资源
resultSet.close();
statement.close();
conn.close(); }
}
C3P0需要在类加载目录下新建c3p0-config.xml
<?xml version="1.0" encoding="utf-8"?>
<c3p0-config>
<default-config>
<property name="driverClass">com.mysql.jdbc.Driver</property>
<property name="jdbcUrl">jdbc:mysql:///java</property>
<property name="user">root</property>
<property name="password">root</property>
</default-config>
</c3p0-config>