小编ele*_*ang的帖子

for (String userName : studentEnrollments.keySet()) {
    System.out.println("Student: " + userName);
    ArrayList<String> courses = studentEnrollments.get(userName);
    String courseMessage = "Courses: ";
    for (String singleCourse : courses) {
        courseMessage += singleCourse + ", ";
        System.out.println(courseMessage);
    }
}

在for循环之后,它会打印出学生正在学习的每门课程.使用逗号打印字符串的正确方法是什么,最后没有最后一个逗号？

例如:AC130,AC140,AC150,AC130,AC140,AC150