studenthandler.java

使用JSP+Servlet+Hibernate+Struts实现的一个学生软件发布平台

package edu.neu.sspp;

import edu.neu.sspp.exception.AddTwiceException;
import edu.neu.sspp.exception.NoStudentsException;
import edu.neu.sspp.exception.StudentNotFoundException;
import edu.neu.sspp.exception.TooManyStudentsException;

public class StudentHandler {
	private String students;
	
	public StudentHandler(String students) {
		this.students = students;
	}
	
	public void addStudent(String student) throws TooManyStudentsException, AddTwiceException{
		if(students == null || students.equals(""))
			students = student;
		else if(students.length() + student.length() > 1024)
			//需要修改成中文
			throw new TooManyStudentsException("too many students");
		else if(students.indexOf(student) != -1)
			//需要修改成中文
			throw new AddTwiceException("you have added him/her");
		else
			students = students + ";" + student;
	}
	
	public void deleteStudent(String student) throws StudentNotFoundException {	
		if(students == null || students.equals(""))
			//需要修改成中文
			throw new StudentNotFoundException("no this student");
		
		int start = students.indexOf(student);
		int end = start + student.length();
		
		StringBuffer studentsBuffer = new StringBuffer(students);		

		if(start == -1)
			//需要修改成中文
			throw new StudentNotFoundException("no this student");
		else if(start != 0)
			studentsBuffer.delete(start - 1, end);
		else
			studentsBuffer.delete(start, end + 1);
		
		students = studentsBuffer.toString();
	}
	
	public String[] getStudentsArray() {
		if(students == null || students.equals(""))
			return null;
		return students.split(";");
	}
	
	public boolean studentAdded(String student) {
		if(students == null || students.equals(""))
			return false;
		else {
			String[] students = getStudentsArray();
			for(int i = 0; i < students.length; i++) {
				if(students[i].equals(student))
					return true;
			}
		}
		return false;
	}
	
	public String getStudents() {
		return students;
	}
}