

实际应用时不需要编写连接数据库代码,直接从数据源获得数据库的连接。程序员编程时也应尽量使用这些数据源的实现,以提升程序的数据库访问性能。
使用时,需要新建java工程,在工程中建立“lib”目录,其中添加c3p0-0.9.1.2.jar和mysql-connector-java-5.0.8-bin.jar(mysql驱动)包,并add to build path。
第一种方法:不使用xml配置文件。
/**
* 演示c3p0的使用方法
* @project_name Day11
* @class_name C3P0Demo
* @author Dovinya
* @data 2014-8-27 下午07:57:42
* @version 1
* @notes
*/
public class C3P0Demo {
@Test
public void operateDatabase() {
Connection conn =null;
PreparedStatement ps = null;
ResultSet rs = null;
try {
// Class.forName("com.mysql.jdbc.Driver");
// conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/day11", "root", "123");
// ps = conn.prepareStatement("select * from account");
ComboPooledDataSource dataSource = new ComboPooledDataSource();
dataSource.setDriverClass("com.mysql.jdbc.Driver");
dataSource.setJdbcUrl("jdbc:mysql://localhost:3306/day11");
dataSource.setUser("root");
dataSource.setPassword("123");
conn = dataSource.getConnection();
ps = conn.prepareStatement("select * from account");
rs = ps.executeQuery();
while(rs.next()){
String name = rs.getString("name");
System.out.println(name);
}
} catch (Exception e) {
e.printStackTrace();
}finally{
if(rs!=null){
try {
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}finally{
rs=null;
}
}
if(ps!=null){
try {
ps.close();
} catch (SQLException e) {
e.printStackTrace();
}finally{
ps=null;
}
}
if(conn!=null){
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}finally{
conn=null;
}
}
}
}
}
先新建xml文件,命名为c3p0-config.xml,在其中添加如下代码:
com.mysql.jdbc.Driver jdbc:mysql:///day11 root 123 3 10 2 10
import com.mchange.v2.c3p0.ComboPooledDataSource;
/**
* 演示c3p0的使用方法
* @project_name Day11
* @class_name C3P0Demo
* @author Dovinya
* @data 2014-8-27 下午07:57:42
* @version 1
* @notes
*/
public class C3P0Demo {
@Test
public void operateDatabase() {
Connection conn =null;
PreparedStatement ps = null;
ResultSet rs = null;
try {
ComboPooledDataSource dataSource = new ComboPooledDataSource();
conn = dataSource.getConnection();
ps = conn.prepareStatement("select * from account");
rs = ps.executeQuery();
while(rs.next()){
String name = rs.getString("name");
System.out.println(name);
}
} catch (Exception e) {
e.printStackTrace();
}finally{
if(rs!=null){
try {
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}finally{
rs=null;
}
}
if(ps!=null){
try {
ps.close();
} catch (SQLException e) {
e.printStackTrace();
}finally{
ps=null;
}
}
if(conn!=null){
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}finally{
conn=null;
}
}
}
}
}
