从Java程序运行时，mysql命令会打印出帮助菜单

Question

我的mysql命令是从Java程序内部运行的，并打印出帮助菜单，但是当我在终端中运行完全相同的命令时，它运行正常。 不太清楚为什么。

String shellCommand = "mysql -u root < " + destinationDirectory+"/"+ filename;
executeCommand(shellCommand);

这是execute命令方法：

public static void executeCommand(String command) {

    StringBuffer output = new StringBuffer();

    Process process;
    try {
        process = Runtime.getRuntime().exec(command);
        JOptionPane.showMessageDialog(null, "COMMAND: "+ command);

        process.waitFor();
        BufferedReader reader =
            new BufferedReader(new InputStreamReader(process.getInputStream()));

        String line = "";
        while ((line = reader.readLine())!= null) {
            output.append(line + "\n");
        }

    } catch (Exception e) {
        JOptionPane.showMessageDialog(null, e.toString());

        e.printStackTrace();
    }

    System.out.println(output.toString());
}  

编辑：这是另一种方法，但是它给了我这个错误，我尝试运行实际的mysql命令而不是像原来那样使用休眠模式，但仍然无济于事。 等待在那里，可以让还原有一些时间到达由于锁定而挂起的位置，然后关闭程序，以便释放锁定和数据库：

// JDBC driver name and database URL
  final String JDBC_DRIVER = "com.mysql.jdbc.Driver";  
  final String DB_URL = "jdbc:mysql://" + HOST + "/" + DATABASE;


   Connection conn = null;
   final Statement stmt;
   try{
      //STEP 2: Register JDBC driver
      Class.forName("com.mysql.jdbc.Driver");

      //STEP 3: Open a connection
      System.out.println("Connecting to a selected database...");
      conn = DriverManager.getConnection(DB_URL, USER, PASS);
      System.out.println("Connected database successfully...");

      //STEP 4: Execute a query
      stmt = conn.createStatement();
        Services.endServices();

        Thread progress = new Thread() {
            @Override
            public void run() {

              try {
                  String sql = "source /mount/mf/outbox/b3sql.sql";
                  stmt.executeUpdate(sql);
                  System.out.println("Database loaded successfully...");

              }catch(SQLException se){
              //Handle errors for JDBC
              se.printStackTrace();
           }
        }

        };
        progress.start();
        TimeUnit.SECONDS.sleep(15);
        System.exit(0); 
   }catch(SQLException se){
      //Handle errors for JDBC
      se.printStackTrace();
   }catch(Exception e){
      //Handle errors for Class.forName
      e.printStackTrace();
   }finally{
      //finally block used to close resources
      try{

            conn.close();
      }catch(SQLException se){
      }// do nothing
      try{
         if(conn!=null)
            conn.close();
      }catch(SQLException se){
         se.printStackTrace();
      }//end finally try
   }//end try

--

com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'source /mount/mf/outbox/b3sql.sql'

Answer 1

您的Shell可以理解输入重定向“ <”，但是Java不能启动Shell！ 尝试这个：

String shellCommand[] =
      {"/usr/bin/mysql", "-h", "127.0.0.1",
       "-u", "myDBuser",
       "--password=aMeHoElA",
       "-e",  "source /here/is/myscript.sql" };
executeCommand(shellCommand);

并修改（命令现在是字符串数组）：

public static void executeCommand(String command[]) {

并且不要忘记阅读错误输出，它将对您有所帮助：

    BufferedReader ereader =
        new BufferedReader(new InputStreamReader(process.getErrorStream()));
    String eline = "";
    while ((eline = ereader.readLine())!= null) {
        output.append("ERROR: " + eline + "\n");

MySQL需要将“ source myscript.txt”作为单个参数。 当您将其与命令的其余部分放在字符串中时，Java会将其作为两个参数传递，这是不可避免的。