java 对象数组排序的问题,急急急急
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发布时间：2022-05-10 07:01
共4个回答
热心网友
时间：2023-07-27 13:36
public class Score implements java.lang.Comparable{
在方法getStuInfomation() 后追加两个方法(compareTo为Comparable接口要求实现此方法，toString为重写基类的打印输出方法)：
public int compareTo(Object otherScore) {
return this.stuScore - ((Score) otherScore).stuScore;
}
public String toString() {
return "[学号:" + stuNumber + "分数:" + stuScore + "姓名:" + stuName + "]";
}
重新编译Score.java,再运行Test,输出结果为：
----------
[学号:3分数:323姓名:Lily]
[学号:5分数:332姓名:Mike]
[学号:2分数:445姓名:Fangfang]
[学号:1分数:472姓名:Liming]
[学号:4分数:540姓名:Green]
-->2008/04/05
哎......
package method2;
import java.util.ArrayList;
import java.util.Collections;
public class Test {
public static void main(String args[]) {
ArrayList list = new ArrayList();
list.add(new Score(1, "Liming", 472));
list.add(new Score(2, "Fangfang", 445));
list.add(new Score(3, "Lily", 323));
list.add(new Score(4, "Green", 540));
list.add(new Score(5, "Mike", 332));
Collections.sort(list, new StuScoreComparator());
for (int i = 0; i < list.size(); i++) {
System.out.println(list.get(i).toString());
}
Collections.binarySearch(list, new Score(1, "Liming", 472));
}
}
class StuScoreComparator extends Score implements java.util.Comparator {
public int compare(Object o1, Object o2) {
Score score1 = (Score) o1;
Score score2 = (Score) o2;
return score1.getStuScore() - score2.getStuScore();
}
}
package method2;
/**
*
* @author Liuchao
*/
public class Score implements java.lang.Comparable {
private int stuNumber;
private String stuName;
private int stuScore;
Score() {
}
public Score(int stuNumber, String stuName, int stuScore) {
if (stuNumber > 0) {
this.stuNumber = stuNumber;
} else {
System.out.println("输入的学生学号不正确");
System.exit(1);
}
if (stuScore > 0) {
this.stuScore = stuScore;
} else {
System.out.println("输入的学生学号不正确");
System.exit(1);
}
this.stuName = stuName;
}//设置学生信息
public void setStuNumber(int stuNumber) {
this.stuNumber = stuNumber;
}//设置学生学号
public void setStuScore(int stuScore) {
this.stuScore = stuScore;
}//设置学生分数
public void setStuName(String stuName) {
this.stuName = stuName;
}//设置学生名字
public int getStuNumber() {
return this.stuNumber;
}//设置学生学号
public int getStuScore() {
return this.stuScore;
}//设置学生分数
public String getStuName() {
return this.stuName;
}//获取学生名字
public String getStuInfomation() {
return "名字：" + this.stuName + " 学号:" + this.stuNumber + " 成绩:" + this.stuScore;
}//获取学生信息
public int compareTo(Object otherScore) {
return this.stuScore - ((Score) otherScore).stuScore;
}
public String toString() {
return "[学号:" + stuNumber + "分数:" + stuScore + "姓名:" + stuName + "]";
}
}
热心网友
时间：2023-07-27 13:36
不过你把每个学生信息都封装成一个对象，数据量如果大的话就有性能这么一说了。
热心网友
时间：2023-07-27 13:37
下面是我修改后的程序，仅供参考：
--------------------------------------------
import java.util.ArrayList;
import java.util.Collections;
public class Test {
public static void main(String args[]) {
ArrayList<Score> list = new ArrayList<Score>();
list.add(new Score(1, "Liming", 472));
list.add(new Score(2, "Fangfang", 445));
list.add(new Score(3, "Lily", 323));
list.add(new Score(4, "Green", 540));
list.add(new Score(5, "Mike", 332));
Collections.sort(list);
for (int i = 0; i < list.size(); i++) {
System.out.println(list.get(i).toString());
}
int n = Collections.binarySearch(list, new Score(1, "Liming", 472));
System.out.println("You found: " + list.get(n));
}
}
/**
*
* @author Liuchao
*/
class Score implements Comparable<Score>{
private int stuNumber;
private String stuName;
private int stuScore;
Score() {
}
public Score(int stuNumber, String stuName, int stuScore) {
if (stuNumber > 0) {
this.stuNumber = stuNumber;
} else {
System.out.println("输入的学生学号不正确");
System.exit(1);
}
if (stuScore > 0) {
this.stuScore = stuScore;
} else {
System.out.println("输入的学生学号不正确");
System.exit(1);
}
this.stuName = stuName;
}// 设置学生信息
public void setStuNumber(int stuNumber) {
this.stuNumber = stuNumber;
}// 设置学生学号
public void setStuScore(int stuScore) {
this.stuScore = stuScore;
}// 设置学生分数
public void setStuName(String stuName) {
this.stuName = stuName;
}// 设置学生名字
public int getStuNumber() {
return this.stuNumber;
}// 设置学生学号
public int getStuScore() {
return this.stuScore;
}// 设置学生分数
public String getStuName() {
return this.stuName;
}// 获取学生名字
// 获取学生信息
public String toString() {
return "名字：" + this.stuName + " 学号:" + this.stuNumber + " 成绩:"
+ this.stuScore;
}
public int compareTo(Score otherScore) {
return this.stuScore - otherScore.stuScore ;
}
}
热心网友
时间：2023-07-27 13:37
