备份mysql数据库的java代码

Question

I tried to run the following code which is to create a backup of my database but it shows some run time errors.

But, I tried to run the System.out.println() output part, (which I've commented in the given code) in mysql shell and it worked .

It shows io file problem. Plz somebody help me.

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

Please check whether your Global PATH environment variable has <Path to MySQL>\\bin in it (Do a echo %PATH% and see). Effectively you should be able to type your System.out.println() content in a Plain DOS prompt and should be able to run it.

Even with that if it doesn't work try changing the code to execute like below

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

This should ideally fix the issue.

UPDATE:

If you don't have it in the PATH environment variable change the code to following

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

Answer 2

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

i tried this one but it didn't work so i replaced it with

this runtimeProcess = Runtime.getRuntime().exec(executeCmd);

and it worked

Answer 3

I solved this problem by giving full path to mysqldump.exe

You can get SO environment variables by

Map<String, String> env = System.getenv();
final String LOCATION = env.get("MYSQLDUMP");

I setup the system variable like this :

• Variable Name : MYSQLDUMP
• Value : D:\\xampp\\mysql\\bin\\mysqldump.exe

Now just execute this code below,

String executeCmd = LOCATION+" -u " + DBUSER + " --add-drop-database -B " + DBNAME + " -r " + PATH + ""+FILENAME
Process runtimeProcess = = Runtime.getRuntime().exec(executeCmd);

Note : If you don't have configured password for mysql server just remove the -p PASSWORD attribute from the code. And don't forget to restart your computer after creating a new system variable.