如何使用Java进行PostgreSQL数据库备份

我想用java使用PostgreSQL数据库进行备份。 我试着用下面的代码，但我得到的是。

错误pg_dump：命令行参数太多（第一个是 "postgres"） 尝试 "pg_dump --help "获取更多信息。

Runtime r = Runtime.getRuntime();
Process p;
ProcessBuilder pb;
r = Runtime.getRuntime();
pb = new ProcessBuilder( 
        "/usr/pgsql-9.3/bin/pg_dump",
        "--host", "localhost",
        "--port", "5432",
        "--username", "postgres",
        "--dbname", "postfixdb",
        "--role", "postgres",
        "--password"," postgres",
        "--verbose",
       "/usr/pg_dump.backup");
pb.redirectErrorStream(true);
p = pb.start();
InputStream is = p.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
String ll;
while ((ll = br.readLine()) != null) { System.out.println(ll); }