Question

请看看我java调用存储过程的代码有什么问题

import java.sql.*;
public class TestCallProcedure {

/**
* @param args
*/
public static void main(String[] args) throws Exception{
// TODO Auto-generated method stub
Class.forName("oracle.jdbc.driver.OracleDriver");
Connection conn=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl", "scott", "tiger");
CallableStatement cstmt=conn.prepareCall("{call p(?,?,?,?)}");
cstmt.registerOutParameter(3, Types.INTEGER);
cstmt.registerOutParameter(4, Types.INTEGER);
cstmt.setInt(1, 3);
cstmt.setInt(2, 4);
cstmt.setInt(4, 6);

System.out.println(cstmt.getInt(3));//有问题，但不知道是什么问题
System.out.println(cstmt.getInt(4));
cstmt.close();
conn.close();
}

}
错误是：
Exception in thread "main" java.lang.NullPointerException
at oracle.jdbc.driver.OracleCallableStatement.getInt(OracleCallableStatement.java:1012)
at TestCallProcedure.main(TestCallProcedure.java:18)

Answer 1

你上面只设了1,2,4的值,唯独3没设值,取的时候当然是空的.
这是该接口方法的签名:
int getInt(int parameterIndex)
throws SQLException
以 Java 编程语言中 int 值的形式获取指定的 JDBC INTEGER 参数的值

Answer 2

去掉“cstmt.setInt(4, 6); ”这一行试试~:)

Answer 3

空指针异常,肯定哪个没取到或指向空了,仔细看看吧~