Calling “mysqldump” with Runtime.getRuntime().exec(cmd) from Windows 7

问题

I am trying to dump a MySQL database within my Java application the following way:

String[] command = new String[] {"cmd.exe", "/c", "C:/mysql/mysqldump.exe" --quick --lock-tables --user=\"root\" --password=\"mypwd\" mydatabase > \"C:/mydump.sql\""};
Process process = Runtime.getRuntime().exec(command);
int exitcode = process.waitFor();

The process fails with exit-code 6. I somewhere read that the operand ">" is not correctly interpreted and there was the hint to use "cmd.exe /c" as prefix. But it still doesn't work.

Any ideas?

回答1:

Yes, you are right , some days ago I made class for exporting DataBase from MySQL... You coud read output sream from console and then write to file

    String[] command = new String[] {"cmd.exe", "/c", "\"C:/Program Files/MySQL/MySQL Server 5.6/bin/mysqldump.exe\" --quick --lock-tables --user=\"root\" --password=\"mypwd\" mydatabase "};
    Process process = Runtime.getRuntime().exec(command);
    BufferedReader input = new BufferedReader(new InputStreamReader(process.getInputStream()));
    while ((line = input.readLine()) != null) {

        System.out.println(line); //there you can write file 
    }
    input.close();

Best Regards

回答2:

Okay here's the final solution. You need to put the "process-reader to file-writer" code into a separate thread and finally wait for the process object to be finished:

    // define backup file
    File fbackup = new File("C:/backup.sql");
    // execute mysqldump command
    String[] command = new String[] {"cmd.exe", "/c", "C:/path/to/mysqldump.exe --quick --lock-tables --user=myuser --password=mypwd mydatabase"};
    final Process process = Runtime.getRuntime().exec(command);
    // write process output line by line to file
    if(process!=null) {
        new Thread(new Runnable() {
            @Override
            public void run() {
                try{
                    try(BufferedReader reader = new BufferedReader(new InputStreamReader(new DataInputStream(process.getInputStream()))); 
                        BufferedWriter writer = new BufferedWriter(new FileWriter(fbackup))) {
                        String line;
                        while((line=reader.readLine())!=null)   {
                            writer.write(line);
                            writer.newLine();
                        }
                    }
                } catch(Exception ex){
                    // handle or log exception ...
                }
            }
        }).start();
    }
    if(process!=null && process.waitFor()==0) {
        // success ...
    } else {
        // failed
    }

On Linux you can directly re-direct the output of the command to a file by using ">" as usual... (and also on Mac OS X I think). So no need for the thread. Generally, please avoid white spaces in your path to the mysqldump/mysqldump.exe file!

来源：https://stackoverflow.com/questions/24887927/calling-mysqldump-with-runtime-getruntime-execcmd-from-windows-7