用java连接mysql出现问题----在线等待回复

[myelan]

代码如下：
import java.sql.*;
public class test
{
public static void main(String[] args)
{
Connection connection = null;
try {
// Load the JDBC driver
//String driverName = "com.mysql.jdbc.Driver"; // MySQL MM JDBC driver
String driverName = "org.gjt.mm.mysql.Driver";
Class.forName(driverName);
// Create a connection to the database
String serverName = "localhost";
String mydatabase = "test";
String url = "jdbc:mysql://" + serverName + "/" + mydatabase; // a JDBC url
String username = "root";
String password = "";
connection = DriverManager.getConnection(url, username, password);

} catch (ClassNotFoundException e) {
// Could not find the database driver
System.out.println("1");
e.printStackTrace();
} catch (SQLException e) {
// Could not connect to the database
System.out.println("2");
}
}
}

执行：
set classpath = F:\algorithm\JDBC\mysql-connector-java-3.1.0-alpha-bin.jar
javac test.java
java test

结果：
java.lang.ClassNotFoundException: org.gjt.mm.mysql.Driver
at java.net.URLClassLoader$1.run(URLClassLoader.java:198)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:186)
at java.lang.ClassLoader.loadClass(ClassLoader.java:299)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:265)
at java.lang.ClassLoader.loadClass(ClassLoader.java:255)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:315)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:140)
at test.main(test.java:11)

[myelan]

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[myelan]

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[newman0708]

好像是classpath中没有你的mysql包，引起

[myelan]

现在我加了也不行啊

[phoenix7789]

呵呵，你的程序我在我的机器上编译并运行过了，没有你说的“java.lang.ClassNotFoundException: org.gjt.mm.mysql.Driver”这个问题。

这个错误的意思是说找不到类，就是mysql的驱动找不到，有几种可能：

1、没有驱动包，或者驱动包的版本和你代码不符合。
2、有驱动包，但是路径不对，找不到。

建议修改方法：
1、改用JCREAT或者JBULIDER编译，你的编译方法可能不对，找不到驱动包。
2、不要用“mysql-connector-java-3.1.0-alpha-bin.jar”的驱动，改用2.0的驱动试试，报名“mysql-connector-java-2.0.14-bin.jar”。
3、如果编译方法没问题，你非要用3.1的驱动，就仔细看看3.1驱动包的说明，因为它的连接字符串可能不是你程序中那样的写法。

我机器上用的2.0的驱动，用你的程序编译成功了。

[myelan]

大哥明示我的编译方法那里不对
你说的
我已经照做了

用了2。0驱动
删除了所有系统的
classpath

执行：
set classpath = F:\algorithm\JDBC\mysql-connector-java-3.1.0-alpha-bin.jar
javac test.java
java test

怎么还出错

[newman0708]

javac -classpath F:\algorithm\JDBC\mysql-connector-java-3.1.0-alpha-bin.jar test.java

你这样你再编译一下试试!

[myelan]

用jcreator解决问题了
用命令行就是不行

哪个大哥，告诉我把

[phoenix7789]

同意！按楼上的格式编译你的程序，但是如果你换成了2.0的驱动，就要把路径换成2.0的路径
javac -classpath F:\algorithm\JDBC\mysql-connector-java-2.0.14-bin.jar test.java

[myelan]

楼上的 newman0708(nch) 你的方法早就用过了
不行的

[myelan]

phoenix7789(火鸟) 你的也不行
我也用过了

[myelan]

怎么样用命令行才可以呢

[myelan]

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[myelan]

结账了 phoenix7789(火鸟) 20

[myelan]

怎么回事，我点击“管理”-“结账“
给了分数，然后出现什么整理FAQ，我确定后，又取消了

然后现在
在贴子里面没有出现给分的情况
但是管理贴子中有，给了 phoenix7789(火鸟) 20分，且不能重新给分了
bug?