数据库连接池之_c3p0

C3p0

　　1,手动设置参数

 @Test
     public void demo1(){
         Connection connection =null;
         PreparedStatement preparedStatement=null;
         ResultSet resultSet=null;
 
         try {
             //设置数据库的相关信息
             ComboPooledDataSource ds=new ComboPooledDataSource();
             ds.setDriverClass("com.mysql.jdbc.Driver");
             ds.setJdbcUrl("jdbc:mysql:///day03");
             ds.setUser("root");
             ds.setPassword("123");
 
             //获取连接
             connection =ds.getConnection();
             String sql="select * from Book";
             preparedStatement=connection .prepareStatement(sql);
             resultSet=preparedStatement.executeQuery();
             while(resultSet.next()){
                 System.out.println(resultSet.getInt("id")+"  "+resultSet.getString("bname"));
             }
         } catch (Exception e) {
             e.printStackTrace();
         }finally{
             //这个是一个工具类用来关闭连接
             JDBCUtils.close(resultSet, preparedStatement, connection);
         }
     }

　　2,自动读取配置文件

　

 @Test
     public void demo2(){
         Connection connection=null;
         PreparedStatement ps=null;
         ResultSet resultSet=null;
         try {
             ComboPooledDataSource cs=new ComboPooledDataSource();//可以在这里设置要使用那个数据库

             connection=cs.getConnection();
             String sql="insert into Book(bname) values(?)";
             ps=connection.prepareStatement(sql);
             ps.setString(1,"牧神记");
             ps.executeUpdate();
 
             ps.setString(1,"一念永恒");
             int num=ps.executeUpdate();
             if(num>0){
                 System.out.println("添加成功");
             }else{
                 System.out.println("添加失败");
             }
         } catch (Exception e) {
             e.printStackTrace();
         }finally{
             JDBCUtils.close(ps, connection);
         }
     }

c3p0的配置文件名(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:///day03</property>
         <property name="user">root</property>
         <property name="password">123</property>
         <property name="minPoolSize">5</property>
         <property name="initialPoolSize">5</property>
     </default-config>
 
     <named-config name="oracle">
          <property name="driverClass">com.mysql.jdbc.Driver</property>
         <property name="jdbcUrl">jdbc:mysql:///day04</property>
         <property name="user">root</property>
         <property name="password">123</property>
         <property name="minPoolSize">5</property>
         <property name="initialPoolSize">5</property>
     </named-config>
</c3p0-config>