Java中list<Object[]>、list<Student>、list<Map<String,String>>排序

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;
                }
            });
        }
    }