Question

我有一个存储过程.. 我想在java中调用该过程。但是，结果没有出来..错误

显示java.lang.NullPointerException

如何在java中调用informix存储过程。请帮我.. 这是我的代码示例..

存储过程

create procedure tryBaru_Procedure(v_name varchar(50),v_city varchar(20),out v_id int)

select id
into v_id
from tryBaru
where name=v_name;

update tryBaru
set city=v_city
where id=v_id;
end procedure;

爪哇

public class TryBaru_Controller {


Connection conn;
DBConnection dbConn = new DBConnection();

public tryBaru p(tryBaru tryje) throws Exception
{
    conn = dbConn.getConnection();

    //prepare call store procedure
    CallableStatement cs = conn.prepareCall("{ call tryBaru_Procedure(?,?,?) }");


    cs.setString(1, tryje.getName());
    cs.setString(2, tryje.getCity());
    cs.registerOutParameter(3, Types.INTEGER);


     cs.executeQuery();
     tryje.setId(cs.getInt(3));
    cs.close();
    conn.close();

    return tryje;
}
}

主要

public static void main(String[] args){
    // TODO Auto-generated method stub

    TryBaru_Controller tbc = new TryBaru_Controller();
    tryBaru tb = new tryBaru();

    String name1 = "Faridah";
    String city1 = "Johor";

    tb.setName(name1);
    tb.setCity(city1);
    try {
        tbc.p(tb);
    } catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    System.out.println(tb.getName());
    System.out.println(tb.getCity());
    System.out.println(tb.getId());

}

Answer 1

你没有包括堆栈跟踪，所以很难说发生了什么。

从您的评论中，您似乎怀疑是Informix JDBC驱动程序。我用JDBC 4.10.JC2DE尝试了类似的代码，它似乎工作。有Jython代码：

"""
    create procedure tryBaru_Procedure(v_name varchar(50),v_city varchar(20),out v_id int)
        let v_id = 10;
    end procedure;
"""

def test_call(db_url, usr, passwd):
    try:
        print("\n\n%s\n--------------\ncall..." % (db_url))
        db = DriverManager.getConnection(db_url, usr, passwd)
        proc = db.prepareCall("{ call tryBaru_Procedure(?, ?, ?) }");
        proc.setString(1, 'v_name')
        proc.setString(2, 'v_city')
        proc.registerOutParameter(3, Types.VARCHAR)
        proc.executeUpdate();
        v_id = proc.getInt(3)
        print('v_id: %s' % (v_id))
        db.close()
    except:
        print("there were errors!")
        s = traceback.format_exc()
        sys.stderr.write("%s\n" % (s))

按预期打印10。

所以也许您使用旧版本的Informix JDBC驱动程序会出现一些错误，但我认为dbConn或conn变量可能存在问题。您确定已连接到数据库吗？

编辑：

如果您只想拥有一个连接（Singleton），请尝试以下方法：

public Connection getConnection() throws Exception {
    /* Define the database to be used, the driver,
    * the connection url, and the username and
    * password to connect the database
    */
    if (connection == null) {
        driver = "com.informix.jdbc.IfxDriver";
        Class.forName(driver);
        connectionURL = "jdbc:informix-sqli://127.0.0.1:9090/barubuat:informixserver=lo_informix1210;user=informix;password=abc123";
        connection = DriverManager.getConnection(connectionURL);
    }
    return connection;
}

在java中调用Informix存储过程

1 个答案: