Java实现类排序

用Java实现类排序? 如下步骤：

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1 待排序的类实现 Comparable 接口

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2? 重写compareTo 方法

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3? Collections.sort(listStu);? 实现排序

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代码如下：

public class Student implements {
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?private int id;
?private String name;
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?public int getId() {
??return id;
?}
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?public void setId(int id) {
??this.id = id;
?}
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?public String getName() {
??return name;
?}
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?public void setName(String name) {
??this.name = name;
?}
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??? public int compareTo(Object arg0) {
??Student student1 = (Student) arg0;
??// 按名字排序27????????
??if(student1.id>this.id){
???return -1;
??}else if(student1.id<this.id){
???return 1;
??}else{
???return 0;
??}
?}
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??? public String toString(){
??? ?String reStr = "";
??? ?reStr += "id=" + id + "? ";
??? ?reStr += "name=" + name + "? ";
??? ?return reStr;
??? }
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}

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import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class TestClass {
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?
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?public static void main(String[] args){
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??List listStu = new ArrayList();
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??Student stu0 = new Student();
??stu0.setId(32);
??listStu.add(stu0);
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??Student stu1 = new Student();
??stu1.setId(12);
??listStu.add(stu1);
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??Student stu2 = new Student();
??stu2.setId(52);
??listStu.add(stu2);
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??Student stu3 = new Student();
??stu3.setId(65);
??listStu.add(stu3);
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??Student stu4 = new Student();
??stu4.setId(21);
??listStu.add(stu4);
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??Student stu5 = new Student();
??stu5.setId(35);
??listStu.add(stu5);
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??Student stu6 = new Student();
??stu6.setId(123);
??listStu.add(stu6);
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??Student stu7 = new Student();
??stu7.setId(78);
??listStu.add(stu7);
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??Student stu8 = new Student();
??stu8.setId(96);
??listStu.add(stu8);
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??Student stu9 = new Student();
??stu9.setId(75);
??listStu.add(stu9);
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??Collections.sort(listStu);
??printList(listStu);?
?}
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?public static void printList(List list){
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??if(list == null || list.size()==0){
???System.out.println("list is null");
??}
??for(int i=0; i<list.size(); i++){
???System.out.println(list.get(i));
??}
?}

}