打印出来是NULL 而另外一个可以连接的显示:com.mysql.jdbc.ConnectionImpl@1f5d386 估计是直接进了catch块,你在catch里面写一句e.printStack(). 看看.发现是这样的错误 java.lang.ClassNotFoundException: com.mysql.jdbc.Driver at java.net.URLClassLoader$1.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClassInternal(Unknown Source) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Unknown Source) at gg.<init>(gg.java:15) at gg.main(gg.java:11)
打印出来是NULL 而另外一个可以连接的显示:com.mysql.jdbc.ConnectionImpl@1f5d386 估计是直接进了catch块,你在catch里面写一句e.printStack(). 看看.发现是这样的错误 java.lang.ClassNotFoundException: com.mysql.jdbc.Driver at java.net.URLClassLoader$1.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClassInternal(Unknown Source) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Unknown Source) at gg.<init>(gg.java:15) at gg.main(gg.java:11)少包,把驱动包加到依赖里去
打印出来是NULL 而另外一个可以连接的显示:com.mysql.jdbc.ConnectionImpl@1f5d386 估计是直接进了catch块,你在catch里面写一句e.printStack(). 看看.发现是这样的错误 java.lang.ClassNotFoundException: com.mysql.jdbc.Driver at java.net.URLClassLoader$1.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClassInternal(Unknown Source) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Unknown Source) at gg.<init>(gg.java:15) at gg.main(gg.java:11) java.lang.ClassNotFoundException: com.mysql.jdbc.Driver把mysql的jar包添加到类路径就好了。
打印出来是NULL 而另外一个可以连接的显示:com.mysql.jdbc.ConnectionImpl@1f5d386 估计是直接进了catch块,你在catch里面写一句e.printStack(). 看看.发现是这样的错误 java.lang.ClassNotFoundException: com.mysql.jdbc.Driver at java.net.URLClassLoader$1.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClassInternal(Unknown Source) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Unknown Source) at gg.<init>(gg.java:15) at gg.main(gg.java:11) java.lang.ClassNotFoundException: com.mysql.jdbc.Driver把mysql的jar包添加到类路径就好了。 我在路径里面已经添加了%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;C:\Program Files\Common Files\Adobe\AGL;F:\phpstudy\phpStudy\MySQL\bin;F:\sdk\jdk\bin;F:\sdk\mysql-connector-java-5.1.7-bin.jar;否则,另外一个项目下面应该也不可能连接成功吧
而另外一个可以连接的显示:com.mysql.jdbc.ConnectionImpl@1f5d386
估计是直接进了catch块,你在catch里面写一句e.printStack(). 看看.
而另外一个可以连接的显示:com.mysql.jdbc.ConnectionImpl@1f5d386
估计是直接进了catch块,你在catch里面写一句e.printStack(). 看看.通过e.printStackTrace();显示的结果是at gg.main(gg.java:11)
而另外一个可以连接的显示:com.mysql.jdbc.ConnectionImpl@1f5d386
估计是直接进了catch块,你在catch里面写一句e.printStack(). 看看.发现是这样的错误
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at gg.<init>(gg.java:15)
at gg.main(gg.java:11)
而另外一个可以连接的显示:com.mysql.jdbc.ConnectionImpl@1f5d386
估计是直接进了catch块,你在catch里面写一句e.printStack(). 看看.发现是这样的错误
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at gg.<init>(gg.java:15)
at gg.main(gg.java:11)少包,把驱动包加到依赖里去
而另外一个可以连接的显示:com.mysql.jdbc.ConnectionImpl@1f5d386
估计是直接进了catch块,你在catch里面写一句e.printStack(). 看看.发现是这样的错误
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at gg.<init>(gg.java:15)
at gg.main(gg.java:11)
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver把mysql的jar包添加到类路径就好了。
而另外一个可以连接的显示:com.mysql.jdbc.ConnectionImpl@1f5d386
估计是直接进了catch块,你在catch里面写一句e.printStack(). 看看.发现是这样的错误
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at gg.<init>(gg.java:15)
at gg.main(gg.java:11)
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver把mysql的jar包添加到类路径就好了。
我在路径里面已经添加了%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;C:\Program Files\Common Files\Adobe\AGL;F:\phpstudy\phpStudy\MySQL\bin;F:\sdk\jdk\bin;F:\sdk\mysql-connector-java-5.1.7-bin.jar;否则,另外一个项目下面应该也不可能连接成功吧
mysql-connector-java-5.1.6-bin要导入工程中eclipse 中只要右击工程文件夹属性选项-Java Build Path-Libraries-Add Extenal JARs 添加即可