字母排序，对象字段排序
字母排序
1 List list = new ArrayList(); 2 list.add("fdd"); 3 list.add("bbc"); 4 list.add("bac"); 5 list.add("abc"); 6 Collections.sort(list); 7 Iterator iterator2 = list.iterator(); 8 while (iterator2.hasNext()) System.out.println(iterator2.next());
1 for (int i = 0; i < list.size(); i++) { 2 System.out.println(list.get(i)); 3 }
实体类中某个字段按字母排序，并“other"字段排最后：
1 List<EntityA> l = new ArrayList<>(); 2 List<EntityA> l1 = new ArrayList<>(); 3 List<EntityA> l2 = new ArrayList<>(); 4 List<EntityA> l3 = new ArrayList<>(); 5 EntityA a1 = new EntityA(); 6 a1.setTa("51"); 7 a1.setTb("阿布"); 8 a1.setTc("other"); 9 a1.setTd("dkwoiweoiei"); 10 EntityA a = new EntityA(); 11 a.setTa("51"); 12 a.setTb("阿布"); 13 a.setTc("bbc"); 14 a.setTd("dkwoiweoiei"); 15 EntityA b = new EntityA(); 16 b.setTa("12"); 17 b.setTb("保持"); 18 b.setTc("zba"); 19 b.setTd("ddssw"); 20 EntityA c = new EntityA(); 21 c.setTa("26"); 22 c.setTb("尺寸"); 23 c.setTc("qwe"); 24 c.setTd("adw"); 25 26 l.add(a); 27 l3.add(a1); 28 l1.add(c); 29 l2.add(b); 30 l.addAll(l1); 31 l2.addAll(l); 32 l3.addAll(l2); 33 Iterator<EntityA> iterator = l3.iterator(); 34 EntityA otherTc = null; 35 while (iterator.hasNext()) { 36 EntityA entityA = iterator.next(); 37 if (entityA.getTc().equals("other")) { 38 otherTc = entityA; 39 iterator.remove(); 40 break; 41 } 42 } 43 Collections.sort(l3); 44 l3.add(otherTc); 45 for (int i = 0; i < l3.size(); i++) { 46 System.out.println(l3.get(i).getTc()); 47 }
1 package com.example.demo; 2 3 import java.io.Serializable; 4 5 public class EntityA implements Serializable,Comparable<EntityA> { 6 //点击File–Setting–Editor–Inspections–Java–Serialization issues–勾选Serializable class without"serialVersionUID"即可，然后点击OK 7 //第二步：选中实体类类名按住Alt+Enter，选择条目，即可生成serialVersionUID 8 private static final long serialVersionUID = -5787205392747829684L; 9 private String tc; 10 private String ta; 11 private String tb; 12 private String td; 13 14 //get/set... 15 16 @Override 17 public int compareTo(EntityA o) { 18 if(this.tc.compareTo(o.tc)<0) 19 return -1; 20 else if(this.tc.compareTo(o.tc)>0) 21 return 1; 22 else return 0; 23 } 24 }
