进一步完成管理类

StudentManager：
- 录入每个学生的学号、姓名和各科考试成绩
- 计算每门课程的总分和平均分
ManagerTool:
- 获取学生总人数
- 获取所有科目名称
- 生成排名信息（按总分）

src/main/java/me/lensfrex/manager/data/ManagerTool.java

@@ -1,15 +1,14 @@
 package me.lensfrex.manager.data;
 
 import java.util.ArrayList;
-import java.util.Comparator;
 import java.util.HashMap;
 import java.util.Map;
 
 public class ManagerTool {
-    private final ArrayList<Student> studentData;
+    private final ArrayList<Student> students;
 
     public ManagerTool(ArrayList<Student> studentData) {
-        this.studentData = studentData;
+        this.students = studentData;
     }
 
     /**
@@ -21,7 +20,7 @@ public class ManagerTool {
      */
     public void addStudent(long id, String name, Map<String, Integer> score) {
         Student student = new Student(id, name, score);
-        studentData.add(student);
+        students.add(student);
     }
 
     /**
@@ -31,12 +30,11 @@ public class ManagerTool {
      * @return 学生的信息，若无该学生则返回null
      */
     public Student getStudent(String name) {
-        for (Student student : studentData) {
+        for (Student student : students) {
             if (student.getName().equals(name)) {
                 return student;
             }
         }
-
         return null;
     }
 
@@ -47,12 +45,11 @@ public class ManagerTool {
      * @return 学生信息，若无该学生则返回null
      */
     public Student getStudent(long id) {
-        for (Student student : studentData) {
+        for (Student student : students) {
             if (student.getId() == id) {
                 return student;
             }
         }
-
         return null;
     }
 
@@ -67,21 +64,20 @@ public class ManagerTool {
      * @return 排序后的学生列表
      */
     public ArrayList<Student> getSortedStudentList(int compareMethod) {
-        ArrayList<Student> sortedStudentList = new ArrayList<>(studentData);
         switch (compareMethod) {
             case SORT_COMPARE_BY_NAME:
-                sortedStudentList.sort(Student.compareByName);
+                students.sort(Student.compareByName);
                 break;
             case SORT_COMPARE_BY_ID:
-                sortedStudentList.sort(Student.compareById);
+                students.sort(Student.compareById);
                 break;
             case SORT_COMPARE_BY_GENERAL_SCORE:
-                sortedStudentList.sort(Student.compareByGeneralScore);
+                students.sort(Student.compareByGeneralScore);
                 break;
             default:
                 break;
         }
-        return sortedStudentList;
+        return students;
     }
 
     /**
@@ -92,7 +88,7 @@ public class ManagerTool {
      */
     public HashMap<String, Integer> getSubjectScores(String subject) {
         HashMap<String, Integer> scores = new HashMap<>();
-        for (Student student : studentData) {
+        for (Student student : students) {
             scores.put(student.getName(), student.getScore().get(subject));
         }
         return scores;
@@ -107,7 +103,7 @@ public class ManagerTool {
         HashMap<String, Integer> result = new HashMap<>();
 
         int scoreSum = 0;
-        for (Student student : studentData) {
+        for (Student student : students) {
             for (int score : student.getScore().values()) {
                 scoreSum += score;
             }
@@ -116,4 +112,41 @@ public class ManagerTool {
         }
         return result;
     }
+
+    /**
+     * 生成排名信息（按总分）
+     *
+     * @return 包含有排名信息的HashMap，key为姓名，value为相应的排名
+     */
+    public HashMap<String, Integer> generateRanking() {
+        HashMap<String, Integer> ranking = new HashMap<>();
+        this.getSortedStudentList(SORT_COMPARE_BY_GENERAL_SCORE);
+
+        for (Student student : students) {
+            ranking.put(student.getName(), students.indexOf(student));
+        }
+        return ranking;
+    }
+
+    /**
+     * 获取所有科目名称，若无学生信息则返回null
+     *
+     * @return 包含所有科目名称的Arraylist，若无学生信息则返回null
+     */
+    public ArrayList<String> getAllSubjects() {
+        if (students.isEmpty()) {
+            return null;
+        }
+        return new ArrayList<>(students.get(0).getScore().keySet());
+    }
+
+    /**
+     * 获取学生总人数
+     *
+     * @return 学生总人数
+     */
+    public int getStudentAmount() {
+        return students.size();
+    }
+
 }

src/main/java/me/lensfrex/manager/data/StudentManager.java

@@ -1,11 +1,95 @@
 package me.lensfrex.manager.data;
 
 import java.util.ArrayList;
+import java.util.HashMap;
 
 public class StudentManager {
-    private ArrayList<Student> studentData = new ArrayList<>();
+    private final ArrayList<Student> students = new ArrayList<>();
+    private final ManagerTool managerTool = new ManagerTool(students);
+    private ArrayList<String> subjects = new ArrayList<>();
 
-    public void addStudent() {
+    /**
+     * 增添学生。输入的字符串格式应为 [id] [name] ...[subjectName,score]
+     * 如： 23333333 Lag English,100 Math,99 History,98
+     *
+     * @param input 待添加的学生信息
+     */
+    public void addStudent(String input) {
+        String[] split = input.split(" ");
 
+        long id = Long.parseLong(split[0]);
+        String name = split[1];
+
+        HashMap<String, Integer> score = new HashMap<>();
+        String[] scoreInput;
+        for (int i = 2; i < split.length; i++) {
+            scoreInput = split[i].split(",");
+            score.put(scoreInput[0], Integer.parseInt(scoreInput[1]));
+        }
+
+        managerTool.addStudent(id, name, score);
+    }
+
+
+    // 要是Java能像go语言那样返回两个返回值就好了...
+    // 这样就能同时返回平均值和总值了...
+    // 做宝可梦.jpg
+    // 还是老老实实写两方法吧...
+
+    /**
+     * 获取班级某科目平均成绩
+     *
+     * @param subject 欲获取的科目
+     * @return 科目平均成绩
+     */
+    public float getSubjectAvgScore(String subject) {
+        return (float) getSubjectScore(subject) / managerTool.getStudentAmount();
+    }
+
+    /**
+     * 获取班级某科目总成绩
+     *
+     * @param subject 欲获取的科目
+     * @return 科目总成绩
+     */
+    public int getSubjectScore(String subject) {
+        ArrayList<Integer> scores = new ArrayList<>(managerTool.getSubjectScores(subject).values());
+        int sum = 0;
+        for (int score : scores) {
+            sum += score;
+        }
+        return sum;
+    }
+
+    /**
+     * 获取每门科目的总成绩
+     *
+     * @return 包含每门课总成绩的HashMap，key为科目名称，value为该科目的总成绩
+     */
+    public HashMap<String, Integer> getAllSubjectScore() {
+        ArrayList<String> subjects = managerTool.getAllSubjects();
+        HashMap<String, Integer> scores = new HashMap<>();
+
+        for (String subject : subjects) {
+            scores.put(subject, getSubjectScore(subject));
+        }
+
+        return scores;
+    }
+
+    /**
+     * 获取每门科目的平均成绩
+     *
+     * @return 包含每门课总成绩的HashMap，key为科目名称，value为该科目的平均成绩
+     */
+    public HashMap<String, Float> getAllSubjectAvgScore() {
+        ArrayList<String> subjects = managerTool.getAllSubjects();
+        HashMap<String, Float> scores = new HashMap<>();
+
+        for (String subject : subjects) {
+            scores.put(subject, getSubjectAvgScore(subject));
+        }
+
+        return scores;
     }
 }

src/main/resources/me.lensfrex.manager/studentInformationExample.txt

@@ -1,4 +1,4 @@
 - Please enter the student information following this format:
   [id] [name] ...[subjectName,score]
 - Example:
-  23333333 Stud English,100 Math,99 History,98
+  23333333 Lag English,100 Math,99 History,98