JNDI InitialContext在简单的netbeans项目中不起作用 [英] JNDI InitialContext not working in simple netbeans project
问题描述
警告:Java的新手
我有一个简单的Netbeans项目-我只想学习与来自php的数据库交互的知识，我想我可以与运行在计算机上的本地数据库一起使用.
I have a simple Netbeans project - I wanted to just learn about interacting with DB's coming from php I thought I would have a go with a local one running on my computer.
许多示例都说明要使用InitialContext()对象来引用数据库资源.
Lots of the examples out there say to use the InitialContext() object to refer to the database resource.
遵循示例之后，我得到以下异常-许多Google内容指向某个.xml文件-我不知道该文件，甚至不知道它在Netbeans项目中的位置吗?我目前不使用Web服务器，因此不使用Tomcat或类似的工具，而仅使用本地Java程序来执行此操作，我怀疑这可能是问题所在.有人能对此有所启发吗?
After following the examples I get the following exception - Lots of Google stuff points to some .xml file - which I have no idea about or even where it exists in the Netbeans project? I'm not using a Webserver at this time so not Tomcat or anything like that, just local Java program to do this, I suspect this might be the problem. Could anyone shed some light on this?
Exception thrown javax.naming.NoInitialContextException: Need to specify class name in environment or system property, or as an applet parameter, or in an application resource file: java.naming.
package learningjava;
import com.mysql.jdbc.jdbc2.optional.*;
import com.mysql.jdbc.Driver;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.naming.*;
public class LearningJava {
public static void main(String[] args) {
MysqlDataSource test_db = new MysqlDataSource();
test_db.setServerName("localhost");
test_db.setDatabaseName("dev");
try {
InitialContext test_db_context = new InitialContext();
test_db_context.bind("jcdb/testdb", test_db);
MysqlDataSource test_db_datasource = (MysqlDataSource)test_db_context.lookup("testdb");
} catch (NamingException e) {
System.out.println("Exception thrown " + e);
}
try {
test_db.getConnection("root","password");
} catch (SQLException e) {
System.out.println("Exception thrown " + e);
}
}
}
推荐答案
通常，您应该了解JNDI应该具有服务器.在您提供的代码段中，当您进行查找时，您正在使用JNDI技术的_CLIENT_SIDE_部分.应该有一个可以从本地客户端连接访问的JNDI服务器. 一旦正确配置，对查询的调用应发出与JNDI服务器的连接，并提供一种获取/绑定该服务器资源的方法.
In general you should understand that JNDI should have a server. In a code snippet you've provided you're using a _CLIENT_SIDE_ part of JNDI technology when you're doing your lookup. There should be a JNDI server that should be accessible from your local client connection. Once configured properly, the call to lookup should issue a connection with JNDI server and provide a way to obtain/bind resources to that server.
如何正确配置JNDI?
How to configure JNDI properly?
通常，您应该提供一个属性文件，其中将包含该服务器的主机名，端口和一些实现特定的信息.
Usually you should supply a properties file that will contain a host name of this server, a port + some implementation specific information.
在使用应用程序服务器(例如JBoss或Web Sphere)时，通常已经提供了JNDI服务器. 我认为这是误会的根源.
JNDI server is usually already provided when you're using application server (like JBoss or Web Sphere). I think this is the root of misunderstanding here.
希望，这会有所帮助
这篇关于JNDI InitialContext在简单的netbeans项目中不起作用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
