1：list<Object[]>的排序
public static void main(String[] args) {
// TODO Auto-generated method stub
Object[] o1 = new Object[4];
o1[0] = "5";
o1[1] = "o1";
o1[2] = "o11";
o1[3] = "o111";
Object[] o2 = new Object[4];
o2[0] = "3";
o2[1] = "o2";
o2[2] = "o22";
o2[3] = "o222";
List<Object[]> list = new ArrayList<>();
list.add(o1);
list.add(o2);
//很明显我们先添加的对象o1，所以先打印o1，
for (inti = 0; i < list.size(); i++) {
for (intj = 0; j < 4; j++) {
System.out.print(list.get(i)[j] + " ");
}
}
System.out.println("\n排序后-------");
sortList(list);
//排序后：
for (inti = 0; i < list.size(); i++) {
for (intj = 0; j < 4; j++) {
System.out.print(list.get(i)[j] + " ");
}
}
}
写一个方法
public staticvoid sortList(List<Object[]> ls) {
Collections.sort(ls, new Comparator<Object[]>() {
@Override
public int compare(Object[] o1, Object[] o2) {
if (Integer.valueOf(o1[0].toString()) > Integer.valueOf(o2[0].toString())) {
return 1;
}
return -1;
}
});
}
2：list<Student>排序，主要是正对汉族的排序，按照拼音排序.
首先写一个Student类
package com.model;
public class Student {
public Stringname;
publicintage;
public Student(Stringname, intage) {
this.name = name;
this.age = age;
}
public void setName(String name) {
this.name = name;
}
public String getName() {
returnname;
}
public void setAge(int age) {
this.age = age;
}
public int getAge() {
returnage;
}
}
然后在main方法中调用，（这里写的是一个java文件）
Student stu1 = new Student("张三", 23);
Student stu2 = new Student("李四", 25);
List<Student> listStudent = new ArrayList<>();
listStudent.add(stu1);
listStudent.add(stu2);
System.out.println();
for (int i = 0; i < listStudent.size(); i++) {
System.out.print(listStudent.get(i).getName() + "---" + listStudent.get(i).getAge());
}
System.out.println("\n排序后");
sortListStudent(listStudent);
for (int i = 0; i < listStudent.size(); i++) {
System.out.print(listStudent.get(i).getName() + "---" + listStudent.get(i).getAge());
}
写一个排序方法
public staticvoid sortListStudent(List<Student> ls) {
Collections.sort(ls, new Comparator<Student>() {
@Override
public int compare(Student o1, Student o2) {
String s1 = o1.getName();
String s2 = o2.getName();
if (s1.compareTo(s2) > 0) {
return -1;
}
return 1;
}
});
}
结果图：
3：list<Map<String,String>>排序问题：
public class MapListSort {
public static void main(String[] args) {
// TODO Auto-generated method stub
List<Map<String, String>> listMap = new ArrayList<>();
Map<String, String> map1 = new HashMap<String, String>();
map1.put("map001", "001");
map1.put("map003", "map003");
map1.put("map002", "map002");
Map<String, String> map2 = new HashMap<String, String>();
map2.put("map001", "101");
map2.put("map003", "map303");
map2.put("map002", "map202");
//先添加的map2，但是map2中map001的值大于map1中的map001的值。
listMap.add(map2);
listMap.add(map1);
for (int i = 0; i < listMap.size(); i++) {
System.out.print(listMap.get(i).get("map001") + "," + listMap.get(i).get("map002") + "," + listMap.get(i).get("map003") + "\n");
}
mapSorts(listMap);
System.out.println("\n排序后：");
for (int i = 0; i < listMap.size(); i++) {
System.out.print(listMap.get(i).get("map001") + "," + listMap.get(i).get("map002") + "," + listMap.get(i).get("map003") + "\n");
}
}
public static void mapSorts(List<Map<String, String>> map) {
Collections.sort(map, new Comparator<Map<String, String>>() {
@Override
public int compare(Map<String, String> o1, Map<String, String> o2) {
// TODO Auto-generated method stub
if (o1.get("map001").compareTo(o2.get("map001")) > 0) {
return 1;
}
return -1;
}
});
}
}