备份mysql数据库的java代码

Question

我试图运行以下代码,即创建我的数据库的备份,但它显示一些运行时错误.

但是,我试图在mysql shell中运行System.out.println()输出部分(我在给定的代码中评论过)并且它有效.

它显示了io文件问题.Plz有人帮助我.

package files;

 public class tableBackup_1 {

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

    String executeCmd = "mysqldump -u " + dbUserName + " -p" + dbPassword + " --add-drop-database -B " + dbName + " -r " + path;
    Process runtimeProcess;
        try
        {
            System.out.println(executeCmd);//this out put works in mysql shell
            runtimeProcess = Runtime.getRuntime().exec(executeCmd);
            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;
}

public static void main(String[] args){

        tableBackup_1 bb = new tableBackup_1();
        bb.tbBackup("test","harin","1234","C:/Users/Master/Downloads/123.sql");

}
}

    mysqldump -u harin -p1234 --add-drop-database -B test -r C:/Users/Master/Downloads/123.sql
java.io.IOException: Cannot run program "mysqldump": CreateProcess error=2, The system cannot find the file specified
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:460)
        at java.lang.Runtime.exec(Runtime.java:593)
        at java.lang.Runtime.exec(Runtime.java:431)
        at java.lang.Runtime.exec(Runtime.java:328)
        at files.tableBackup_1.tbBackup(tableBackup_1.java:12)
        at files.tableBackup_1.main(tableBackup_1.java:34)
Caused by: java.io.IOException: CreateProcess error=2, The system cannot find the file specified
        at java.lang.ProcessImpl.create(Native Method)
        at java.lang.ProcessImpl.<init>(ProcessImpl.java:81)
        at java.lang.ProcessImpl.start(ProcessImpl.java:30)
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:453)
        ... 5 more

Answer 1

请检查您的Global PATH环境变量是否包含<Path to MySQL>\bin(Do a echo %PATH%and see).实际上,您应该能够在Plain DOS提示符下键入System.out.println()内容,并且应该能够运行它.

即使这样,如果它不起作用尝试更改代码执行如下所示

runtimeProcess = Runtime.getRuntime().exec(new String[] { "cmd.exe", "/c", executeCmd });

这应该理想地解决问题.

更新:

如果在PATH环境变量中没有它,请将代码更改为以下内容

String executeCmd = "<Path to MySQL>/bin/mysqldump -u " + dbUserName + " -p" + dbPassword + " --add-drop-database -B " + dbName + " -r " + path;