如何按等級對文件進行排序？

Question

這是一個按ID排序文件的完整程序。不過，我想按等級對它進行分類。我修改了幾次，但似乎沒有工作。有人可以指示我在哪裏更改ID以評分。另外，你認爲這個代碼可以簡化嗎？還是有其他代碼比這個代碼更簡單。

對不起，不好的縮進，這個源代碼也可以找到here。

student.txt文件：

4 A 87 A 
5 B 99 A+ 
1 C 75 A 
2 D 55 C 
3 E 68 B 

源：

import java.io.*; 
import java.util.*; 

    class ShowData implements Comparable { 
    int id; 
    String name; 
    int marks; 
    String grade; 

    public void setId(int id) { 
      this.id = id; 
    } 

    public int getId() { 
      return id; 
    } 

    public void setName(String name) { 
      this.name = name; 
    } 

    public String getName() { 
      return name; 
    } 

    public void setMarks(int marks) { 
      this.marks = marks; 
    } 

    public int getMarks() { 
      return marks; 
    } 

    public void setGrade(String grade) { 
      this.grade = grade; 
    } 

    public String getGrade() { 
      return grade; 
    } 

    public int compareTo(Object Student) throws ClassCastException { 
      if (!(Student instanceof ShowData)) 
        throw new ClassCastException("Error"); 
      int ide = ((ShowData) Student).getId(); 
      return this.id - ide; 
    } 
    } 



public class SortFile { 
    SortFile() { 
    int j = 0; 
    ShowData data[] = new ShowData[5]; 
    try { 
    FileInputStream fstream = new FileInputStream("C:/student.txt"); 
    // Use DataInputStream to read binary NOT text. 
    BufferedReader br = new BufferedReader(new InputStreamReader(fstream)); 
    String strLine; 
    ArrayList list = new ArrayList(); 
    while ((strLine = br.readLine()) != null) { 
    list.add(strLine); 
    } 

Iterator itr; 
    for (itr = list.iterator(); itr.hasNext();) { 
    String str = itr.next().toString(); 
    String[] splitSt = str.split(" "); 
    String id = "", name = "", marks = "", grade = ""; 
    for (int i = 0; i < splitSt.length; i++) { 
    id = splitSt[0]; 
    name = splitSt[1]; 
    marks = splitSt[2]; 
    grade = splitSt[3]; 
    } 
    data[j] = new ShowData(); 
    data[j].setId(Integer.parseInt(id)); 
    data[j].setName(name); 
    data[j].setMarks(Integer.parseInt(marks)); 
    data[j].setGrade(grade); 
    j++; 
    } 

Arrays.sort(data); 
    File file = new File("C:/new.txt"); 
    FileWriter fw = new FileWriter(file, true); 
    BufferedWriter out = new BufferedWriter(fw); 
    System.out.println("********Sorted by id********"); 
    String strVal = ""; 
    for (int i = 0; i < 5; i++) { 
    ShowData show = data[i]; 
    int no = show.getId(); 
    String name = show.getName(); 
    int marks = show.getMarks(); 
    String grade = show.getGrade(); 
    System.out.println(no + " " + name + " " + marks + " " + grade); 
    String d = no + " " + name + " " + marks + " " + grade; 
    ArrayList al = new ArrayList(); 
    al.add(d + "\n"); 
    Iterator itr1 = al.iterator(); 
    while (itr1.hasNext()) { 
    out.write(itr1.next().toString()); 
    out.newLine(); 
    } 
    } 
    out.close(); 
    } catch (Exception e) { 
    } 
    } 
public static void main(String[] args) { 
      SortFile data = new SortFile(); 
    } 
    } 

Answer 1

的的compareTo（）方法目前比較的ID，而不是等級。嘗試比較 標記。