用带有斜杠的字符串变量替换硬编码字符串

Question

在下面的代码中，我试图用变量"dumppath“替换转储路径，该变量具有与命令中的字符串相同的确切字符，但是当我用变量替换它时，它总是给出一个IOException，其中说系统找不到指定的文件。但是，通过硬编码的路径，它工作得很好。

public String dumppath = "C:\\wamp\\bin\\mysql\\mysql5.6.12\\bin\\mysqldump";

public void backupDatabase() {//GEN-FIRST:event_jButton1ActionPerformed

        try {

            int processComplete; // to verify that either process completed or not

            //Process runtimeProcess = Runtime.getRuntime().exec("C:\\wamp\\bin\\mysql\\mysql5.6.12\\bin\\mysqldump -u root mysql -r F:/backup.sql");
            Process runtimeProcess = Runtime.getRuntime().exec("'"+dumppath+"' -u root mysql -r F:/backup.sql");
// call the mysqldump in terminal and execute it
            processComplete = runtimeProcess.waitFor();//store the state in variable

            if (processComplete == 1) {//if values equal 1 process failed

                JOptionPane.showMessageDialog(null, "Backup Failed");//display message
            } else if (processComplete == 0) {//if values equal 0 process failed
                System.out.println("Backup up : "+backuppath);
                System.out.println("Dump Path : "+dumppath);
                JOptionPane.showMessageDialog(null, "\n Backup created Successfully..\n Check the Backup File in the D: Directory named as backup.sql");
//display message
            }

        } catch (Exception e) {

            JOptionPane.showMessageDialog(null, e);//exeception handling

        }

// TODO add your handling code here:
    }

Answer 1

Process runtimeProcess = Runtime.getRuntime().exec( "'"+dumppath+"' -u root mysql -r F:/backup.sql");

是一样的

Process runtimeProcess = Runtime.getRuntime().exec(
 "'C:\\wamp\\bin\\mysql\\mysql5.6.12\\bin\\mysqldump' -u root mysql -r F:/backup.sql");

与硬编码字符串相比，它有两个更多的单引号。

要获得原始字符串，您应该尝试如下所示

String dumppath = "C:\\wamp\\bin\\mysql\\mysql5.6.12\\bin\\mysqldump";
Process runtimeProcess = Runtime.getRuntime().exec( dumppath+" -u root mysql -r F:/backup.sql");

或

String command = "C:\\wamp\\bin\\mysql\\mysql5.6.12\\bin\\mysqldump -u root mysql -r F:/backup.sql";
Process runtimeProcess = Runtime.getRuntime().exec(command); 

Answer 2

 Process runtimeProcess = Runtime.getRuntime().exec(
   "C:\\wamp\\bin\\mysql\\mysql5.6.12\\bin\\mysqldump -u root mysql -r F:/backup.sql");
 Process runtimeProcess = Runtime.getRuntime().exec(
   "'"+dumppath+"' -u root mysql -r F:/backup.sql");

这些调用中的第一个在路径周围没有单引号。