java 连接 mysql 错误信息

Question

这是什么错误信息呢？
程序里是连接数据库的代码！ 如果需要代码 我可以贴出代码~
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Exception in thread "main" java.net.BindException: Address already in use: JVM_Bind
at java.net.PlainSocketImpl.socketBind(Native Method)
at java.net.PlainSocketImpl.bind(Unknown Source)
at java.net.ServerSocket.bind(Unknown Source)
at java.net.ServerSocket.<init>(Unknown Source)
at java.net.ServerSocket.<init>(Unknown Source)
at src.Server.main(Server.java:185)

Answer 1

1,独立运行的Tomcat没有关闭.
自安装的tomcat程序设置开机自动运行,或者在之前运行过,先关闭ecplipse或jbuilder,在任务管理器中找到Tomcat的进程,将其kill掉,即可.有时候Tomcat非法关闭时,在进程中,仍然存在,仍然占用8080端口.所以只要将其进程杀掉.就可以解决.
 
2,安装了其他的软件占用了Tomcat的端口.
用可以查看端口的工具查看一下,或者,直接改掉tomcat的默认端口.即可.参考下

Answer 2

那下面的错误信息是什么意思呢？
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Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at src.New.login_mouseClicked(New.java:128)
at src.New$1.mouseClicked(New.java:63)
at java.awt.AWTEventMulticaster.mouseClicked(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

Answer 3

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
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空指针异常.

Answer 4

AWT GUI component .....

Answer 5

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at src.New.login_mouseClicked(New.java:128)
at src.New$1.mouseClicked(New.java:63)
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在你的New.java的63行处调用的方法mouseClicked中调用的方法login_mouseClicked方法中第(New.java的128行)出现了对null或者未实例化的对象进行了访问(操作).

Answer 6

或者说你这是调用的方法中你给传进了null.具体可以看一下api,查找一下这个方法抛空指针异常时的情况,看看你是不是这种情况