myweb.rar_java MVC_mvc_mvc.zip_mvc选课_选课系统 java

package services; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.File; import java.io.FileOutputStream; import java.io.FileReader; import java.io.OutputStreamWriter; import java.util.Iterator; import java.util.LinkedList; import java.util.List; import javabeans.Course; public class CourseService { private final List list = new LinkedList(); private int newID = 0; private String filename = ""; public CourseService(String filename) { this.filename = filename; synchronized (list) { if (list.isEmpty()) { cacheCourses(); } } } public List getList() { return list; } protected void cacheCourses() { try { int maxID = 0; BufferedReader br = new BufferedReader(new FileReader(filename)); String line = ""; while (true) { line = br.readLine(); if (line == null || line.equals("")) break; String[] data = line.split("\t"); int id = Integer.parseInt(data[0]); String title = data[1]; Course course = new Course(id, title); list.add(course); if (maxID < id) maxID = id; } newID = maxID; br.close(); } catch (Exception e) { System.out.println(e.getMessage()); } } public Course createCourse(String title) { Iterator items = list.iterator(); while (items.hasNext()) { Course course = (Course) items.next(); if (course.getTitle().equals(title)) { return null; } } int id = newID + 1; Course newCourse = new Course(id, title); storeCourse(newCourse); list.add(newCourse); return newCourse; } protected void storeCourse(Course course) { try { FileOutputStream fos = new FileOutputStream(filename, true); BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(fos)); bw.write(course.getID() + "\t" + course.getTitle() + "\n"); bw.flush(); fos.close(); } catch (Exception e) { System.out.println(e.getMessage()); } } protected void storeAllCourses() { try { FileOutputStream os = new FileOutputStream(filename, false); BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(os)); Iterator items = list.iterator(); while (items.hasNext()) { Course course = (Course) items.next(); bw.write(course.getID() + "\t" + course.getTitle() + "\n"); } bw.flush(); os.close(); } catch (Exception e) { System.out.println(e.getMessage()); } } public void deleteCourse(Course course) { if (list.contains(course)) { list.remove(course); storeAllCourses(); } } public Course getCourse(String title) { Iterator items = list.iterator(); while (items.hasNext()) { Course course = (Course) items.next(); if (course.getTitle().equals(title)) { return course; } } return null; } // for SelectionService public Course getCourse(int id) { Iterator items = list.iterator(); while (items.hasNext()) { Course course = (Course) items.next(); if (course.getID() == id) { return course; } } return null; } public boolean updateCourse(Course course) { Iterator items = list.iterator(); boolean updatable = false; while (items.hasNext()) { Course tempCourse = (Course) items.next(); if (tempCourse.getID() == course.getID()) { tempCourse.setTitle(course.getTitle()); updatable = true; break; } } if (updatable) storeAllCourses(); return updatable; } public static void main(String[] args) { File file = new File(""); String currentDir = file.getAbsolutePath(); CourseService cs = new CourseService(currentDir + "\\WebContent\\data\\courses.dat"); // cs.createCourse("OOAD"); // Course course1 = new Course(106, "OOAD"); // cs.deleteCourse(course1); // Course course1 = cs.getCourse("信息检索"); // System.out.println(course1.getID()); // Course course1 = new Course(103, "数据库系统原理"); // System.out.println(cs.updateCourse(course1)); Iterator items = cs.getList().iterator(); while (items.hasNext()) { Course course = (Course) items.next(); System.out.println(course.getID() + ":" + course.getTitle()); } } }