Why does java process hang executing mysqldump?

Question

I want to backup database in mysql 5.6.
For this I use this method:

public boolean backupDB(String dbName, String dbUserName, String dbPassword, String path) {

        String executeCmd = "D://mysql-5.6.11-win32/bin/mysqldump -u " + dbUserName + " -p" + dbPassword
                + " --add-drop-database -B " + dbName + " -r " + path;
        Process runtimeProcess;
        try {

            runtimeProcess = Runtime.getRuntime().exec(executeCmd);
            // any error message?
            StreamGobbler errorGobbler = new StreamGobbler(runtimeProcess.getErrorStream(), "ERR");
            // any output?
            StreamGobbler outputGobbler = new StreamGobbler(runtimeProcess.getInputStream(), "OUT");
            // kick them off
            errorGobbler.start();
            outputGobbler.start();

            int processComplete = runtimeProcess.waitFor();

            if (processComplete == 0) {
                System.out.println("Backup created successfully");
                return true;
            } else {
                System.out.println("Could not create the backup");
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }

        return false;
    }

StreamGobbler is Thread that wraps runtimeProcess.getErrorStream() and runtimeProcess.getInputStream() into BufferedReader. BufferedReader merely reads line by line using readLine() method. This is a hint I got on this article .

My problem is that method backupDB hangs on this line :

int processComplete = runtimeProcess.waitFor();

If I substitute waitFor method with exitValue I receive error

java.lang.IllegalThreadStateException: process has not exited

Therefore I must use waitFor method. And unfortunately it runs forever. I must press red icon on eclipse console to stop the JVM.

How to make process complete and backup mysql database? This is solved thanks!

EDIT To launch mysqldump.exe I need to write full path to it :

String executeCmd = "D://mysql-5.6.11-win32/bin/mysqldump -u "

Don't you know how to get rid of full path. I want to launch mysqldump independently on mysqldump.exe location on computer.

Maybe there is a way to get the path to mysqldump.exe having all connection details.

EDIT If I try to use mysqldump without full path to mysqldump.exe I receive this exception :

java.io.IOException: Cannot run program "mysqldump": CreateProcess error=2, Íå óäàåòñÿ íàéòè óêàçàííûé ôàéë
    at java.lang.ProcessBuilder.start(ProcessBuilder.java:1029)
    at java.lang.Runtime.exec(Runtime.java:615)
    at java.lang.Runtime.exec(Runtime.java:448)
    at java.lang.Runtime.exec(Runtime.java:345)
    at dbViewer.model.ConnectionManager.backupDB(ConnectionManager.java:273)
    at dbViewer.model.ConnectionManager.main(ConnectionManager.java:337)
Caused by: java.io.IOException: CreateProcess error=2, Íå óäàåòñÿ íàéòè óêàçàííûé ôàéë
    at java.lang.ProcessImpl.create(Native Method)
    at java.lang.ProcessImpl.<init>(ProcessImpl.java:189)
    at java.lang.ProcessImpl.start(ProcessImpl.java:133)
    at java.lang.ProcessBuilder.start(ProcessBuilder.java:1021)
    ... 5 more

Thanks!

Answer 1

您可以简单地使用mysqldump -p选项：

mysqldump –u[user name] –p[password] [database name] > [dump file]