JDBC复习

 

一，JDBC的编程步骤：   --学自尚学堂

1.Load the Driver，向DriverManager注册
①.Class.forName(“该Driver的名字”)或者是Class.forName(“该Driver的名字”).newInstance()或者直接new这个Driver
②.实例化时自动向DriverManager注册，不需要再调用DriverManager.registerDriver方法

2.Connect to the DataBase
①.DriverManager.getConnec()

3.Excute the SQL
①.Connection.CreateStatem()
②.Statement.executeQuery()
③.Statement.executeUpdate()

4.Retrieve the result data      Retrieve （检索储存的信息）
①.循环取得结果 while(rs.next())

5.Show the result data
①.将数据库中的各种类型转换为java中的类型，用get方法

6.Close   （后打开的先关）
①.close the ResultSet
②.close the Statement
③.close the Connection

二，Oracle的连接字符串

    Class.forName("oracle.jdbc.driver.OracleDriver");
conn = DriverManager.getConnection("jdbc:oracle:thin:@主机IP:1521:所要连接的数据库的SID","scott","tiger");

一个连接的Format

public static void main(String[] args) { Connection conn = null; try { //向DriverManager注册 Class.forName("oracle.jdbc.driver.OracleDriver");     //从DriverManager获得连接     conn = DriverManager.getConnection("jdbc:oracle:thin:@192.168.1.210:1521:orcl","scott","tiger"); } catch (ClassNotFoundException e) { e.printStackTrace(); } finally { //最后关闭连接 if (conn != null){ conn.close(); conn = null; } } catch (SQLException e) { e.printStackTrace(); } } }

三，执行查询SQL时的Format

public static void main(String[] args) { Connection conn = null; Statement stmt = null; ResultSet rs = null; try { Class.forName("oracle.jdbc.driver.OracleDriver"); conn = DriverManager.getConnection("jdbc:oracle:thin:@192.168.1.210:1521:orcl","scott","tiger"); //创建Statement，然后通过Statement的executeQuery(sql)方法执行查询语句，并把结果返回到ResultSet结果集中     stmt = conn.createStatement(); String sql = "select * from dept"; rs = stmt.executeQuery(sql);     while (rs.next()){ System.out.println(rs.getInt("deptno")); } } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); } finally { //最后关闭所有资源，后打开的先关，关闭后赋值为null是为了让垃圾收集器尽快释放内存 try { if (rs != null){ rs.close(); rs = null; } if (stmt != null){ stmt.close(); stmt = null; } if (conn != null){ conn.close(); conn = null; } } catch (SQLException e) { e.printStackTrace(); } } }

四，执行insert，update等对表进行改动的SQL时的Format

public static void main(String[] args) { Connection conn = null; Statement stmt = null; ResultSet rs = null; PreparedStatement pstmt = null; try { Class.forName("oracle.jdbc.driver.OracleDriver"); conn = DriverManager.getConnection("jdbc:oracle:thin:@192.168.1.210:1521:orcl","scott","tiger"); //建立prepareStatement，通过prepareStatement的executeUpdate方法执行SQL语句？是占位符，这样写SQL就更方便，避免了单引号的问题     pstmt = conn.prepareStatement("insert into dept2 values (?,?,?)"); pstmt.setInt(1, 50); pstmt.setString(2, "GAME"); pstmt.setString(3, "BEIJING"); pstmt.executeUpdate(); } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); } finally { try { if (rs != null){ rs.close(); rs = null; } if (stmt != null){ stmt.close(); stmt = null; } if (conn != null){ conn.close(); conn = null; } } catch (SQLException e) { e.printStackTrace(); } } }

五，调用PLSQL时的Format

① 先建立一个Stored Procedure

create or replace procedure p (v_a in number, v_b number, v_return out number, v_temp in out number) is begin if (v_a > v_b) then v_return := v_a; else v_return := v_b; end if; v_temp := v_temp + 1; end;

② java中的写法

public static void main(String[] args) { Connection conn = null; try { Class.forName("oracle.jdbc.driver.OracleDriver"); conn = DriverManager.getConnection("jdbc:oracle:thin:@192.168.1.210:1521:orcl", "scott", "tiger"); //建立一个CallableStatement ，然后通过CallableStatement 的execute方法来执行PLSQL     CallableStatement cstmt = conn.prepareCall("{call p(?,?,?,?)}"); cstmt.registerOutParameter(3, Types.INTEGER); cstmt.registerOutParameter(4, Types.INTEGER); cstmt.setInt(1, 13); cstmt.setInt(2, 45); cstmt.setInt(4, 9); cstmt.execute(); System.out.println(cstmt.getInt(3)); System.out.println(cstmt.getInt(4)); } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); } }

六，在JDBC中处理Batch
①

public static void main(String[] args) { Connection conn = null; Statement stmt = null; try { Class.forName("oracle.jdbc.driver.OracleDriver"); conn = DriverManager.getConnection("jdbc:oracle:thin:@192.168.1.210:1521:orcl", "scott", "tiger"); stmt = conn.createStatement(); //用Statement的addBatch方法把各个SQL语句添加进去，然后在调用executeBatch语句执行这些SQL语句     stmt.addBatch("insert into dept2 values(51,'lit1','tokyo')"); stmt.addBatch("insert into dept2 values(52,'lit2','tokyo')"); stmt.addBatch("insert into dept2 values(53,'lit3','tokyo')"); stmt.executeBatch();    } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); } finally { try { if (conn != null){ conn.close(); conn = null; } } catch (SQLException e){ e.printStackTrace(); } } }

②

public static void main(String[] args) { Connection conn = null; PreparedStatement pstmt = null; try { Class.forName("oracle.jdbc.driver.OracleDriver"); conn = DriverManager.getConnection("jdbc:oracle:thin:@192.168.1.210:1521:orcl", "scott", "tiger"); pstmt = conn.prepareStatement("insert into dept2 values(?,?,?)"); //调用PreparedStatement 的addBatch加入各种SQL语句，然后调用executeBatch方法执行这些SQL语句 pstmt.setInt(1, 61); pstmt.setString(2, "lit1"); pstmt.setString(3, "okayama"); pstmt.addBatch(); pstmt.setInt(1, 62); pstmt.setString(2, "lit2"); pstmt.setString(3, "okayama"); pstmt.addBatch(); pstmt.setInt(1, 63); pstmt.setString(2, "lit3"); pstmt.setString(3, "okayama"); pstmt.addBatch(); pstmt.executeBatch();    } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); } finally { try { if (conn != null) { conn.close(); conn = null; } if (pstmt != null) { pstmt.close(); pstmt = null; } } catch (SQLException e) { e.printStackTrace(); } } }

七，JDBC中的事物处理，transaction，（就是关于commit）

public static void main(String[] args) { Connection conn = null; Statement stmt = null; try { Class.forName("oracle.jdbc.driver.OracleDriver"); conn = DriverManager.getConnection("jdbc:oracle:thin:@192.168.1.210:1521:orcl", "scott", "tiger"); stmt = conn.createStatement();    //首先用Connection中的setAutoCommit方法将自动commit设为false，因为JDBC默认是自动commit，执行完所要执行的语句块后再用Connection的commit方法提交，完成后setAutoCommit(true)，恢复JDBC的默认设置 conn.setAutoCommit(false);     stmt.addBatch("insert into dept2 values(41,'lit1','tokyo')"); stmt.addBatch("insert into dept2 values(42,'lit2','tokyo')"); stmt.addBatch("insert into dept2 values(43,'lit3','tokyo')"); stmt.executeBatch(); conn.commit(); conn.setAutoCommit(true);    } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); //捕捉到任何的SQLException立刻rollback，然后恢复JDBC的默认设置    try { if(conn != null) { conn.rollback(); conn.setAutoCommit(true); } } catch (SQLException e1) { e1.printStackTrace(); }    } finally { try { if (conn != null){ conn.close(); conn = null; } } catch (SQLException e){ e.printStackTrace(); } } }

转自 http://hi.baidu.com/ahuzl/blog/item/c3b900d10a02a987a0ec9cce.html