Statement，PreparedStatement和PreparedStatement的简介

a.Statement对象

1)Statement;(简单语句) addBatch() and executeBatch()方法

Statement stmt=conn.createStatement();

stmt.addBatch(“”);

stmt.addBatch(“”);

int []results=stmt.executeBatch();

2) 使用方法Connection.createStatement()得到一个Statement对象

b. PreparedStatement(继承自Statement); （预编译语句）

1) 调用ProparedStatement比statement更为高效;
2)   继承自StatredStatement

3）PreparedStatement pstm =connection.prepareStatement(“update mytable set name=?”+”where acctnum=123”);

pstm.setDate(1,sqlDate);

c.CallableStatement对象 （可调用语句）
1) 通过CallableStatement调用数据库中的存储过程;
2) 继承自PreparedStatement;
3) CallableStatement cstm = connection.prepareCall("{callreturn_student[?,?]}");
cstm.setString(1,"8623034");
cstm.registerOutparameter(2, Types.REAL);
cstm.execute();
float gpa = cstm.getFloat(2);