通过CallableStatement调用存储过程时,“参数不是OUT参数”错误

时间:2014-08-22 00:26:54

标签: java mysql stored-procedures callable-statement

我一直在尝试在MySQL Workbanch中创建的调用过程“proc”:

create database test_database;
use test_database;

delimiter &&
create procedure proc(inout param INT UNSIGNED)
begin
    set param = 2*param;
end&&

使用此应用程序:

package test;

import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;

public class Test {

public static void main(String[] args) {
    try {
        Class.forName("com.mysql.jdbc.Driver");
        Connection connection = DriverManager.getConnection("jdbc:mysql://127.0.0.1", "root", "root");
        connection.createStatement().execute("USE test_database");
        CallableStatement callableStatement = connection.prepareCall("{call proc(?)}");
        callableStatement.setInt(1, 5);
        callableStatement.registerOutParameter(1, java.sql.Types.INTEGER);
        ResultSet result = callableStatement.executeQuery();
        if (result.first()) {
            System.out.println(result.getInt(1));
        }            
    } catch (Exception ex) {
        ex.printStackTrace();
    }
}}

但我总是得到这个错误:

java.sql.SQLException: Parameter number 1 is not an OUT parameter
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1094)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:997)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:983)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:928)
at com.mysql.jdbc.CallableStatement.checkIsOutputParam(CallableStatement.java:695)
at com.mysql.jdbc.CallableStatement.registerOutParameter(CallableStatement.java:2016)
at test.Test.main(Test.java:16)

我一直试图找出错误很多小时,但没有成功。 我看到很多问题,但是: this is useless because in function cannot be transaction

this is useless because when i use named parameter NullPointerEx is throwed(why??)

this is useless because procedure exists, and dont throw any exception when i use only IN param, but with INOUT or OUT is throwed mentioned exception

this is useless because i cant see any obvious mistake

this is useless because update JDBC connector didnt help

所以我的问题很简单:任何想法可能出错?

1 个答案:

答案 0 :(得分:0)

我会尝试两件事:

  1. 使用"jdbc:mysql://127.0.0.1/test_database"连接字符串,然后移除execute("USE test_database")
  2. 的来电
  3. 交换setIntregisterOutParameter行。
  4. 一般来说,执行USE test_database应该没问题,但MySQL documentation明确提醒使用它:

      

    始终使用Connection.setCatalog()方法在JDBC应用程序中指定所需的数据库,而不是USE database语句。

    虽然上下文略有不同,但似乎同样的建议也适用于您的情况。