调用"mysqldump".使用Windows 7中的Runtime.getRuntime().exec(cmd)

问题描述

我正尝试通过以下方式在Java应用程序中转储MySQL数据库:

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();

该过程失败，退出代码为6.我在某处读取到操作数>"的解释不正确，并且提示使用"cmd.exe/c"作为前缀.但这仍然行不通.

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.

有什么想法吗?

推荐答案

好的，这是最终解决方案.您需要将进程读取器到文件写入器"代码放入单独的线程中，最后等待进程对象完成:

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
    }

在Linux上，您可以像往常一样使用>"将命令的输出直接重定向到文件...(以及我认为在Mac OS X上).因此不需要线程.通常，请避免在mysqldump/mysqldump.exe文件的路径中出现空格！

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!

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