backup mysql database java code

问题

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

回答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;

回答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

回答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.

来源：https://stackoverflow.com/questions/13376132/backup-mysql-database-java-code