Java使用MySQL实现连接池代码实例

/**
   * 手动设置连接池
   */
  public void demo1(){

    // 获得连接:
    Connection conn = null;
    PreparedStatement pstmt = null;
    ResultSet rs = null;
    try{
      // 创建连接池:
      ComboPooledDataSource dataSource = new ComboPooledDataSource();
      // 设置连接池的参数:
      dataSource.setDriverClass("com.mysql.jdbc.Driver");
      dataSource.setJdbcUrl("jdbc:mysql:///jdbctest");
      dataSource.setUser("root");
      dataSource.setPassword("abc");
      dataSource.setMaxPoolSize(20);
      dataSource.setInitialPoolSize(3);
      
      // 获得连接:
      conn = dataSource.getConnection();
      // 编写Sql:
      String sql = "select * from user";
      // 预编译SQL:
      pstmt = conn.prepareStatement(sql);
      // 设置参数
      // 执行SQL:
      rs = pstmt.executeQuery();
      while(rs.next()){
        System.out.println(rs.getInt("uid")+"  "+rs.getString("username")+"  "+rs.getString("password")+"  "+rs.getString("name"));
      }
    }catch(Exception e){
      e.printStackTrace();
    }finally{
      JDBCUtils.release(rs, pstmt, conn);
    }
  }

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>

 <default-config>
  <property name="driverClass">com.mysql.jdbc.Driver</property>
  <property name="jdbcUrl">jdbc:mysql:///jdbctest</property>
  <property name="user">root</property>
  <property name="password">abc</property>
  <property name="initialPoolSize">5</property>
  <property name="maxPoolSize">20</property>
 </default-config>
 
</c3p0-config>

/**
   * 使用配置文件的方式
   */
  public void demo2(){
    Connection conn = null;
    PreparedStatement pstmt = null;
    ResultSet rs = null;
    try{
      /*// 获得连接:
      ComboPooledDataSource dataSource = new ComboPooledDataSource();*/
      // 获得连接:
      // conn = dataSource.getConnection();
      conn = JDBCUtils2.getConnection();
      // 编写Sql:
      String sql = "select * from user";
      // 预编译SQL:
      pstmt = conn.prepareStatement(sql);
      // 设置参数
      // 执行SQL:
      rs = pstmt.executeQuery();
      while(rs.next()){
        System.out.println(rs.getInt("uid")+"  "+rs.getString("username")+"  "+rs.getString("password")+"  "+rs.getString("name"));
      }
    }catch(Exception e){
      e.printStackTrace();
    }finally{
      JDBCUtils2.release(rs, pstmt, conn);
    }
  }