DRP——JDBC中的Batch

在jdbc2.0里添加了批量处理的功能（batch），其同意将多个sql语句作为一个单元送至数据库去运行，这样做能够提高操作效率。在操作大量的数据时,
ORM框架实现批量是非常慢的。我们能够使用jdbc提供的Batch来提高效率。

演示样例：

首先是使用for循环，一句一句的运行：

public class TestCommon {
	static long startTime;
	public static void main(String[] args) throws Exception {  

        Connection conn = getConnection();
        PreparedStatement ps = null;
        try {
        	startTime=System.nanoTime();   //获取開始时间
            ps = conn
                    .prepareStatement("INSERT INTO batchtab  values (?, ?

)");
            conn.setAutoCommit(false);
            for (int n = 0; n < 10000; n++) {
                Integer i = new Integer(n);
                ps.setString(1, i.toString());
                ps.setString(2, "value" + i.toString());
                ps.executeUpdate();
            }
            conn.commit();
            long endTime=System.nanoTime(); //获取结束时间
            System.out.println("程序执行时间： "+(endTime-startTime)+"ns");
        }catch (SQLException ex) {
            System.out.println("SQLException: " + ex.getMessage());
            System.out.println("SQLState: " + ex.getSQLState());
            System.out.println("Message: " + ex.getMessage());
            System.out.println("Vendor error code: " + ex.getErrorCode());
        } catch (Exception e) {
            e.printStackTrace();
            System.err.println("Exception: " + e.getMessage());
        } finally {
            if (conn != null)
                conn.close();
            if (ps != null)
                ps.close();
        }
    }  

    public static Connection getConnection() {
    	  Connection con = null;  //创建用于连接数据库的Connection对象
          try {
              Class.forName("com.mysql.jdbc.Driver");// 载入Mysql数据驱动  

              con = DriverManager.getConnection(
                      "jdbc:mysql://localhost:3306/TestBatch", "root", "123456");// 创建数据连接  

          } catch (Exception e) {
              System.out.println("数据库连接失败" + e.getMessage());
          }
          return con; //返回所建立的数据库连接
    }
}

使用Batch，批量操作：

public class TestPreStatementBatch {
	static long startTime;
	public static void main(String[] args) throws Exception {  

        Connection conn = getConnection();
        ResultSet rs = null;
        PreparedStatement ps=null;
        try {  

        	 startTime=System.nanoTime();   //获取開始时间  

            ps = conn.prepareStatement("INSERT INTO batchtab values (?

, ?

)");
            conn.setAutoCommit(false);
            ps.clearBatch();  

            for (int n=0; n<10000; n++) {
            	Integer i = new Integer(n);
                ps.setString(1, i.toString());
                ps.setString(2, "value" + i.toString());
                ps.addBatch();
            }
            ps.executeBatch();
            conn.commit();
            long endTime=System.nanoTime(); //获取结束时间
            //打印消耗时间
            System.out.println("程序执行时间： "+(endTime-startTime)+"ns");
        } catch (BatchUpdateException b) {
            System.out.println("SQLException: " + b.getMessage());
            System.out.println("SQLState: " + b.getSQLState());
            System.out.println("Message: " + b.getMessage());
            System.out.println("Vendor error code: " + b.getErrorCode());
            System.out.print("Update counts: ");  

        } catch (SQLException ex) {
            System.out.println("SQLException: " + ex.getMessage());
            System.out.println("SQLState: " + ex.getSQLState());
            System.out.println("Message: " + ex.getMessage());
            System.out.println("Vendor error code: " + ex.getErrorCode());
        } catch (Exception e) {
            e.printStackTrace();
            System.err.println("Exception: " + e.getMessage());
        } finally {
            if( conn != null )
            conn.close();
         if(ps !=null)
            ps.close();
            if(rs !=null)
            rs.close();   

        }
    }  

	public static Connection getConnection() {
  	  Connection con = null;  //创建用于连接数据库的Connection对象
        try {
            Class.forName("com.mysql.jdbc.Driver");// 载入Mysql数据驱动  

            con = DriverManager.getConnection(
                    "jdbc:mysql://localhost:3306/TestBatch", "root", "123456");// 创建数据连接  

        } catch (Exception e) {
            System.out.println("数据库连接失败" + e.getMessage());
        }
        return con; //返回所建立的数据库连接
  }
}