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>