1. package com.heima.test;
   
2. 
   
3. import java.io.BufferedReader;
   
4. import java.io.BufferedWriter;
   
5. import java.io.FileNotFoundException;
   
6. import java.io.FileOutputStream;
   
7. import java.io.FileWriter;
   
8. import java.io.IOException;
   
9. import java.io.InputStreamReader;
   
10. import java.io.OutputStreamWriter;
    
11. import java.util.Scanner;
    
12. import java.util.Set;
    
13. import java.util.TreeSet;
    
14. 
    
15. /**
    
16. * 6. 有五个学生，每个学生有3门课的成绩，从键盘输入以上数据（包括姓名，三门课成绩），
    
17. * 计算出总成绩，并把学生的信息和计算出的总分数存放在磁盘文件"stud.txt"中。
    
18. *
    
19. * @author wangming1988
    
20. *
    
21. */
    
22. public class StudentTreeSet {
    
23. 
    
24. public static void main(String[] args) {
    
25. Set<Student2> stuSet = getStudentSetByReadSystemIn();
    
26. write2StuTxt(stuSet);
    
27. }
    
28. 
    
29. private static Set<Student2> getStudentSetByReadSystemIn() {
    
30. System.out.println("姓名 语文 数学 英语");
    
31. BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    
32. Set<Student2> stus = new TreeSet<Student2>();
    
33. try {
    
34. for (String line = null; (line = br.readLine()) != null;) {
    
35. if ("exit".equals(line))
    
36. break;
    
37. Scanner scanner = new Scanner(line);
    
38. String name = scanner.next();
    
39. int chineseScore = scanner.nextInt();
    
40. int mathScore = scanner.nextInt();
    
41. int englishScore = scanner.nextInt();
    
42. stus.add(new Student2(name, chineseScore, mathScore,
    
43. englishScore));
    
44. }
    
45. } catch (IOException e) {
    
46. e.printStackTrace();
    
47. } finally {
    
48. try {
    
49. if (br != null)
    
50. br.close();
    
51. } catch (IOException e) {
    
52. e.printStackTrace();
    
53. }
    
54. }
    
55. return stus;
    
56. }
    
57. 
    
58. private static void write2StuTxt(Set<Student2> stus) {
    
59. BufferedWriter bw = null;
    
60. /*
    
61. * bw = new BufferedWriter(new OutputStreamWriter( new
    
62. * FileOutputStream("stuScore.txt")));
    
63. */
    
64. try {
    
65. bw = new BufferedWriter(new FileWriter("stuScore.txt"));
    
66. } catch (IOException e) {
    
67. e.printStackTrace();
    
68. }
    
69. 
    
70. try {
    
71. bw.write("姓名 语文 数学 英语 总分（升序）");
    
72. bw.newLine();
    
73. bw.flush();
    
74. for (Student2 student2 : stus) {
    
75. bw.write(student2.toString());
    
76. bw.newLine();
    
77. bw.flush();
    
78. }
    
79. } catch (IOException e) {
    
80. e.printStackTrace();
    
81. } finally {
    
82. try {
    
83. if (bw != null)
    
84. bw.close();
    
85. } catch (IOException e) {
    
86. e.printStackTrace();
    
87. }
    
88. }
    
89. }
    
90. 
    
91. }
    
92. 
    
93. /**
    
94. * 被比较的对象也是Student2
    
95. *
    
96. * @author wangming1988
    
97. *
    
98. */
    
99. class Student2 implements Comparable<Student2> {
    
100. /* 姓名做主键吧 */
     
101. private String name;
     
102. 
     
103. private int chineseScore;
     
104. 
     
105. private int mathScore;
     
106. 
     
107. private int englishScore;
     
108. 
     
109. private int total;
     
110. 
     
111. public Student2(String name, int chineseScore, int mathScore,
     
112. int englishScore) {
     
113. super();
     
114. this.name = name;
     
115. this.chineseScore = chineseScore;
     
116. this.mathScore = mathScore;
     
117. this.englishScore = englishScore;
     
118. }
     
119. 
     
120. public String getName() {
     
121. return name;
     
122. }
     
123. 
     
124. public void setName(String name) {
     
125. this.name = name;
     
126. }
     
127. 
     
128. public int getChineseScore() {
     
129. return chineseScore;
     
130. }
     
131. 
     
132. public void setChineseScore(int chineseScore) {
     
133. this.chineseScore = chineseScore;
     
134. }
     
135. 
     
136. public int getMathScore() {
     
137. return mathScore;
     
138. }
     
139. 
     
140. public void setMathScore(int mathScore) {
     
141. this.mathScore = mathScore;
     
142. }
     
143. 
     
144. public int getEnglishScore() {
     
145. return englishScore;
     
146. }
     
147. 
     
148. public void setEnglishScore(int englishScore) {
     
149. this.englishScore = englishScore;
     
150. }
     
151. 
     
152. public int getTotal() {
     
153. return this.mathScore + this.chineseScore + this.englishScore;
     
154. }
     
155. 
     
156. @Override
     
157. public int hashCode() {
     
158. final int prime = 31;
     
159. int result = 1;
     
160. result = prime * result + chineseScore;
     
161. result = prime * result + englishScore;
     
162. result = prime * result + mathScore;
     
163. result = prime * result + ((name == null) ? 0 : name.hashCode());
     
164. result = prime * result + getTotal();
     
165. return result;
     
166. }
     
167. 
     
168. @Override
     
169. public boolean equals(Object obj) {
     
170. if (this == obj)
     
171. return true;
     
172. if (obj == null)
     
173. return false;
     
174. if (getClass() != obj.getClass())
     
175. return false;
     
176. Student2 other = (Student2) obj;
     
177. if (chineseScore != other.chineseScore)
     
178. return false;
     
179. if (englishScore != other.englishScore)
     
180. return false;
     
181. if (mathScore != other.mathScore)
     
182. return false;
     
183. if (name == null) {
     
184. if (other.name != null)
     
185. return false;
     
186. } else if (!name.equals(other.name))
     
187. return false;
     
188. if (getTotal() != other.getTotal())
     
189. return false;
     
190. return true;
     
191. }
     
192. 
     
193. @Override
     
194. public String toString() {
     
195. return name + " " + chineseScore + " " + mathScore + " "
     
196. + englishScore + " " + getTotal();
     
197. }
     
198. 
     
199. /**
     
200. * 返回值为0，说明两人总分相同。 返回值小于0，说明小于你选取的比较对象。 返回值大于0，说明大于你选取的比较对象。
     
201. */
     
202. @Override
     
203. public int compareTo(Student2 o) {
     
204. int result = 0;
     
205. if (o instanceof Student2) {
     
206. Student2 stu = (Student2) o;
     
207. result = stu.getTotal() - o.getTotal();
     
208. }
     
209. return result;
     
210. }
     
211. }
     

复制代码

上图：

1. package com.heima.test;
   
2. 
   
3. import java.io.BufferedReader;
   
4. import java.io.BufferedWriter;
   
5. import java.io.FileNotFoundException;
   
6. import java.io.FileOutputStream;
   
7. import java.io.FileWriter;
   
8. import java.io.IOException;
   
9. import java.io.InputStreamReader;
   
10. import java.io.OutputStreamWriter;
    
11. import java.util.Scanner;
    
12. import java.util.Set;
    
13. import java.util.TreeSet;
    
14. 
    
15. /**
    
16. * 6. 有五个学生，每个学生有3门课的成绩，从键盘输入以上数据（包括姓名，三门课成绩），
    
17. * 计算出总成绩，并把学生的信息和计算出的总分数存放在磁盘文件"stud.txt"中。
    
18. *
    
19. * @author wangming1988
    
20. *
    
21. */
    
22. public class StudentTreeSet {
    
23. 
    
24. public static void main(String[] args) {
    
25. Set<Student2> stuSet = getStudentSetByReadSystemIn();
    
26. write2StuTxt(stuSet);
    
27. }
    
28. 
    
29. private static Set<Student2> getStudentSetByReadSystemIn() {
    
30. System.out.println("姓名 语文 数学 英语");
    
31. BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    
32. Set<Student2> stus = new TreeSet<Student2>();
    
33. try {
    
34. for (String line = null; (line = br.readLine()) != null;) {
    
35. if ("exit".equals(line))
    
36. break;
    
37. Scanner scanner = new Scanner(line);
    
38. String name = scanner.next();
    
39. int chineseScore = scanner.nextInt();
    
40. int mathScore = scanner.nextInt();
    
41. int englishScore = scanner.nextInt();
    
42. stus.add(new Student2(name, chineseScore, mathScore,
    
43. englishScore));
    
44. }
    
45. } catch (IOException e) {
    
46. e.printStackTrace();
    
47. } finally {
    
48. try {
    
49. if (br != null)
    
50. br.close();
    
51. } catch (IOException e) {
    
52. e.printStackTrace();
    
53. }
    
54. }
    
55. return stus;
    
56. }
    
57. 
    
58. private static void write2StuTxt(Set<Student2> stus) {
    
59. BufferedWriter bw = null;
    
60. /*
    
61. * bw = new BufferedWriter(new OutputStreamWriter( new
    
62. * FileOutputStream("stuScore.txt")));
    
63. */
    
64. try {
    
65. bw = new BufferedWriter(new FileWriter("stuScore.txt"));
    
66. } catch (IOException e) {
    
67. e.printStackTrace();
    
68. }
    
69. 
    
70. try {
    
71. bw.write("姓名 语文 数学 英语 总分（升序）");
    
72. bw.newLine();
    
73. bw.flush();
    
74. for (Student2 student2 : stus) {
    
75. bw.write(student2.toString());
    
76. bw.newLine();
    
77. bw.flush();
    
78. }
    
79. } catch (IOException e) {
    
80. e.printStackTrace();
    
81. } finally {
    
82. try {
    
83. if (bw != null)
    
84. bw.close();
    
85. } catch (IOException e) {
    
86. e.printStackTrace();
    
87. }
    
88. }
    
89. }
    
90. 
    
91. }
    
92. 
    
93. /**
    
94. * 被比较的对象也是Student2
    
95. *
    
96. * @author wangming1988
    
97. *
    
98. */
    
99. class Student2 implements Comparable<Student2> {
    
100. /* 姓名做主键吧 */
     
101. private String name;
     
102. 
     
103. private int chineseScore;
     
104. 
     
105. private int mathScore;
     
106. 
     
107. private int englishScore;
     
108. 
     
109. private int total;
     
110. 
     
111. public Student2(String name, int chineseScore, int mathScore,
     
112. int englishScore) {
     
113. super();
     
114. this.name = name;
     
115. this.chineseScore = chineseScore;
     
116. this.mathScore = mathScore;
     
117. this.englishScore = englishScore;
     
118. }
     
119. 
     
120. public String getName() {
     
121. return name;
     
122. }
     
123. 
     
124. public void setName(String name) {
     
125. this.name = name;
     
126. }
     
127. 
     
128. public int getChineseScore() {
     
129. return chineseScore;
     
130. }
     
131. 
     
132. public void setChineseScore(int chineseScore) {
     
133. this.chineseScore = chineseScore;
     
134. }
     
135. 
     
136. public int getMathScore() {
     
137. return mathScore;
     
138. }
     
139. 
     
140. public void setMathScore(int mathScore) {
     
141. this.mathScore = mathScore;
     
142. }
     
143. 
     
144. public int getEnglishScore() {
     
145. return englishScore;
     
146. }
     
147. 
     
148. public void setEnglishScore(int englishScore) {
     
149. this.englishScore = englishScore;
     
150. }
     
151. 
     
152. public int getTotal() {
     
153. return this.mathScore + this.chineseScore + this.englishScore;
     
154. }
     
155. 
     
156. @Override
     
157. public int hashCode() {
     
158. final int prime = 31;
     
159. int result = 1;
     
160. result = prime * result + chineseScore;
     
161. result = prime * result + englishScore;
     
162. result = prime * result + mathScore;
     
163. result = prime * result + ((name == null) ? 0 : name.hashCode());
     
164. result = prime * result + getTotal();
     
165. return result;
     
166. }
     
167. 
     
168. @Override
     
169. public boolean equals(Object obj) {
     
170. if (this == obj)
     
171. return true;
     
172. if (obj == null)
     
173. return false;
     
174. if (getClass() != obj.getClass())
     
175. return false;
     
176. Student2 other = (Student2) obj;
     
177. if (chineseScore != other.chineseScore)
     
178. return false;
     
179. if (englishScore != other.englishScore)
     
180. return false;
     
181. if (mathScore != other.mathScore)
     
182. return false;
     
183. if (name == null) {
     
184. if (other.name != null)
     
185. return false;
     
186. } else if (!name.equals(other.name))
     
187. return false;
     
188. if (getTotal() != other.getTotal())
     
189. return false;
     
190. return true;
     
191. }
     
192. 
     
193. @Override
     
194. public String toString() {
     
195. return name + " " + chineseScore + " " + mathScore + " "
     
196. + englishScore + " " + getTotal();
     
197. }
     
198. 
     
199. /**
     
200. * 返回值为0，说明两人总分相同。 返回值小于0，说明小于你选取的比较对象。 返回值大于0，说明大于你选取的比较对象。
     
201. */
     
202. @Override
     
203. public int compareTo(Student2 o) {
     
204. int result = 0;
     
205. if (o instanceof Student2) {
     
206. Student2 stu = (Student2) o;
     
207. result = stu.getTotal() - o.getTotal();
     
208. }
     
209. return result;
     
210. }
     
211. }
     

复制代码

上图：