针对ArrayList中的某个属性进行排序

针对ArrayList中的某个属性进行排序

 

 

1.创建要比较的对象

  

public class ExampleObj{
 private Long prop;
 private String name;
  public ExampleObj(Long prop,String name){
      this.prop= prop;
      this.name= name;  
 }
 public Long getProp() {
     return prop;
 }
 public void setProp(Long prop) {
  this.prop= prop;
 }
 public String getName() {
  return name;
 }
 public void setName(String name) {
  this.name = name;
 }
}

 

2.实现java.util.Comparator<T>接口

 

import java.io.Serializable;
import java.util.Comparator;public class ComparatorExampleObj implements Comparator<ExampleObj>,Serializable {
 public int compare(ExampleObj o1, ExampleObj o2) {
  ExampleObj p1 = (ExampleObj) o1;
  ExampleObj p2 = (ExampleObj) o2;
  //按升序排列
  if (p1.getProp() > p2.getProp())
   return 1;
  else
   return 0;
 }
}

3.排序

ArrayList list = new ArrayList();
  list.add(new ExampleObj (1,"name1"));
  list.add(new ExampleObj (3,"name3"));
  list.add(new ExampleObj (2,"name2")); 
ComparatorExampleObj comp = new ComparatorExampleObj ();
  Collections.sort(list,comp);  //此时list为以按prop属性进行过升序排序的集合类