用Java实现SQL数据库备份

我尝试了几种方法让代码正常工作，并从MAMP备份了一个数据库，但最接近的方法是更新一个空的sql文件，但不打印其中的任何内容

谁能帮帮我吗。多谢各位

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at guidesign.LoginPage.btn_loginActionPerformed(LoginPage.java:175)
    at guidesign.LoginPage.access$000(LoginPage.java:16)
    at guidesign.LoginPage$1.actionPerformed(LoginPage.java:73)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2346)
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
    at java.awt.Component.processMouseEvent(Component.java:6525)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
    at java.awt.Component.processEvent(Component.java:6290)
    at java.awt.Container.processEvent(Container.java:2234)
    at java.awt.Component.dispatchEventImpl(Component.java:4881)
    at java.awt.Container.dispatchEventImpl(Container.java:2292)
    at java.awt.Component.dispatchEvent(Component.java:4703)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4898)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4533)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4462)
    at java.awt.Container.dispatchEventImpl(Container.java:2278)
    at java.awt.Window.dispatchEventImpl(Window.java:2739)
    at java.awt.Component.dispatchEvent(Component.java:4703)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:746)
    at java.awt.EventQueue.access$400(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:697)
    at java.awt.EventQueue$3.run(EventQueue.java:691)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:86)
    at java.awt.EventQueue$4.run(EventQueue.java:719)
    at java.awt.EventQueue$4.run(EventQueue.java:717)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:716)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)








        try {
            Runtime runtime = Runtime.getRuntime();
            Process p = runtime.exec("C:/Applications/MAMP/Library/bin/mysqldump -u root -p pass db > C:/Desktop/Backup.sql");

            int processComplete = p.waitFor();

            if (processComplete == 0) {

                System.out.println("Backup created successfully!");

            } else {
                backupMsg.setText("Could not create the backup");
            }


        } catch (Exception e) {
            e.printStackTrace();
        }

---

你有例外吗？流程是否成功完成？在有人回答之前，你必须给出更多的细节。线程“AWT-EventQueue-0”java.lang.NullPointerExceptionSorry中的异常，它说我得到了一个空指针异常，并且该过程没有完成。如果你将完整的堆栈跟踪作为答案的一部分发布，这将更有用。stacktrace可以指向导致异常的确切代码行。异常发生在第175行的

btn\u loginActionPerformed（）

方法中。由于缺少这方面的源代码，我真的不知道哪里出了问题，但您应该从那里开始搜索。