How to backup a postgres database using java

Question

this is the code I am using to back up my database using pg_dump 9.3 in java. The problem I have is that always the result file is empty, and the exit code is 1, any ideas?

public static void backupDb() throws IOException, InterruptedException {
    Runtime rt = Runtime.getRuntime();
    Process p;
    ProcessBuilder pb;
    rt = Runtime.getRuntime();
    pb = new ProcessBuilder(
            "C:\\Program Files\\PostgreSQL\\9.3\\bin\\pg_dumpall.exe",
            "--host", "localhost",
            "--port", "5432",
            "--username", "postgres",
            "--no-password",
            "--format", "custom",
            "--blobs",
            "--verbose", "--file", "D:\\service_station_backup.backup", "service_station");
    p = pb.start();
    p.waitFor();
    System.out.println(p.exitValue());
}

Answer 1

thanks everyone for help, finally could find the perfect code.

public static void exportDb2() throws IOException, InterruptedException {
    Runtime rt = Runtime.getRuntime();
    Process p;
    ProcessBuilder pb;
    rt = Runtime.getRuntime();
    pb = new ProcessBuilder(
            "C:\\Program Files\\PostgreSQL\\9.3\\bin\\pg_dump.exe",
            "--host", "localhost",
            "--port", "5432",
            "--username", "postgres",
            "--no-password",
            "--format", "custom",
            "--blobs",
            "--verbose", "--file", "D:\\service_station_backup.backup", "service_station");
    try {
        final Map<String, String> env = pb.environment();
        env.put("PGPASSWORD", "admin");
        p = pb.start();
        final BufferedReader r = new BufferedReader(
                new InputStreamReader(p.getErrorStream()));
        String line = r.readLine();
        while (line != null) {
            System.err.println(line);
            line = r.readLine();
        }
        r.close();
        p.waitFor();
        System.out.println(p.exitValue());

    } catch (IOException | InterruptedException e) {
        System.out.println(e.getMessage());
    }
}

Answer 2

For psql , the "long options" need an equal sign: = . So it needs to be eg --host=localhost . For that you need to pass those arguments as a single String argument to ProcessBuilder:

pb = new ProcessBuilder(
        "C:\\Program Files\\PostgreSQL\\9.3\\bin\\pg_dumpall.exe",
        "--host=localhost",
        "--port=5432",
        "--username=postgres",
        "--no-password",
        "--format=custom",
        "--blobs",
        "--verbose", "--file=D:\\service_station_backup.backup", "service_station");

You should also capture the error output of the ProcessBuilder using ProcessBuilder.getErrorStream() to see any error message from psql . You probably want to capture the regular output as well (using getInputStream() )

---

Edit

The error message you get:

fe_sendauth: no password supplied

means you have to provide a password.

You can do that by passing a connection URL to pg_dump.

pb = new ProcessBuilder(
        "C:\\Program Files\\PostgreSQL\\9.3\\bin\\pg_dumpall.exe",
        "--dbname=postgres://postgres:password@localhost/postgres",
        "--format=custom",
        "--blobs",
        "--verbose", "--file=D:\\service_station_backup.backup", "service_station");