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jdbc fetchsize_Sharding-JDBC

JDBC Sharding
2023-06-13 09:13:00 时间

大家好，又见面了，我是你们的朋友全栈君。

DBUtils

commons-dbutils是Apache组织提供的一个开源JDBC工具类库，封装了针对于数据库的增删改查操作

API

  • QueryRunner
  • ResulSetHandler
  • Dbutils

插入举例

Connection conn = null;
        try { 
   
            QueryRunner runner = new QueryRunner();
            conn = JBBCUtils.getConnections3();
            String sql = "insert into customers(name,emial,birth) values(?,?,?)";
            int insertCount = runner.update(conn,sql,"蔡旭坤","caixukun@163.com","1993-03-01");
            System.out.println(insertCount);
        } catch (SQLException throwables) { 
   
            throwables.printStackTrace();
        }finally { 
   
            JDBCUtils.closeResource(conn,null);
        }

更新

    public static void main(String[] args) { 
   

        Connection conn = null;
        try { 
   
            QueryRunner runner = new QueryRunner();
            conn = JBBCUtils.getConnections3();
            String sql = "select id,name,email,birth from customers where id < ?";
            BeanListHandler<Customer> handler = new BeanListHandler<Cunstomer>(customer.class);
            List<Customer> query = runner.query(conn.sql, handler, 23);
            System.out.println(insertCount);
        } catch (SQLException throwables) { 
   
            throwables.printStackTrace();
        }finally { 
   
            JDBCUtils.closeResource(conn,null);
        }
    }

查询表中特殊值

public static void main(String[] args) { 
   

        Connection conn = null;
        try { 
   
            QueryRunner runner = new QueryRunner();
            conn = JBBCUtils.getConnections3();
            String sql = "select count(*) from customers";
            ScalarHandler handler = new ScalarHandler();
            
            Long count = (Long)runner.query(conn.sql, handler);
            System.out.println(count);
        } catch (SQLException throwables) { 
   
            throwables.printStackTrace();
        }finally { 
   
            JDBCUtils.closeResource(conn,null);
        }
    }

自定义ResultSetHandler

public static void main(String[] args) { 
   

        Connection conn = null;
        try { 
   
            QueryRunner runner = new QueryRunner();
            conn = JBBCUtils.getConnections3();
            String sql = "select id,name,email,birth from customers where id = ?";
            ResultSetHandler<Customers> resultSetHandler = new ResultSetHandler<Customers>() { 
   
                @Override
                public Customers handle(ResultSet rs) throws SQLException { 
   
                    if(resultSet.next()){ 
   
                        int id = rs.getInt(1);
                        String name = rs.getString(2);
                        String email = rs.getString(3);
                        Date birth = rs.getDate(4);
                        Customer customer = new Cunstomer(id,name,email,birth);
                        return customer;
                    }
                    return null;
                }
            };

            Long count = (Long)runner.query(conn.sql, handler);
            System.out.println(count);
        } catch (SQLException throwables) { 
   
            throwables.printStackTrace();
        }finally { 
   
            JDBCUtils.closeResource(conn,null);
        }
    }

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