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标题: set集合奈何只add了一个对象？【已解决，自己粗心啦】 [打印本页]
作者: 王勃    时间: 2012-5-27 14:40
标题: set集合奈何只add了一个对象？【已解决，自己粗心啦】
本帖最后由 王明（1988） 于 2012-5-27 15:11 编辑

  1. package com.heima.test;

  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;

  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 {

  24. public static void main(String[] args) {
  25. Set<Student2> stuSet = getStudentSetByReadSystemIn();
  26. write2StuTxt(stuSet);
  27. }

  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. }

  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. }

  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. }

  91. }

  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;

  103. private int chineseScore;

  105. private int mathScore;

  107. private int englishScore;

  109. private int total;

  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. }

  120. public String getName() {
  121. return name;
  122. }

  124. public void setName(String name) {
  125. this.name = name;
  126. }

  128. public int getChineseScore() {
  129. return chineseScore;
  130. }

  132. public void setChineseScore(int chineseScore) {
  133. this.chineseScore = chineseScore;
  134. }

  136. public int getMathScore() {
  137. return mathScore;
  138. }

  140. public void setMathScore(int mathScore) {
  141. this.mathScore = mathScore;
  142. }

  144. public int getEnglishScore() {
  145. return englishScore;
  146. }

  148. public void setEnglishScore(int englishScore) {
  149. this.englishScore = englishScore;
  150. }

  152. public int getTotal() {
  153. return this.mathScore + this.chineseScore + this.englishScore;
  154. }

  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. }

  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. }

  193. @Override
  194. public String toString() {
  195. return name + " " + chineseScore + " " + mathScore + " "
  196. + englishScore + " " + getTotal();
  197. }

  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. }
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