list排序,根据list中存放对象的某一属性排序

时间:2022-02-05 19:34:02

1.Student的Bean如下:

public class Student {

private int age;

private String name;

private String weight;

public String getWeight() {
return weight;
}

public void setWeight(String weight) {
this.weight = weight;
}

public int getAge() {
return age;
}

public void setAge(int age) {
this.age = age;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}
}


2.按照List中对象的Int类型属性进行排序

   /**
* 按照List中的某个Int类型的属性进行排序
* @param list
*/
@SuppressWarnings("unchecked")
public static void sortIntMethod(List list){
Collections.sort(list, new Comparator(){
@Override
public int compare(Object o1, Object o2) {
Student stu1=(Student)o1;
Student stu2=(Student)o2;
if(stu1.getAge()>stu2.getAge()){
return 1;
}else if(stu1.getAge()==stu2.getAge()){
return 0;
}else{
return -1;
}
}
});
System.out.println("/////////////排序之后///////////////");
for(int i=0;i<list.size();i++){
Student st=(Student)list.get(i);
System.out.println("st.age="+st.getAge()+",st.name="+st.getName());
}
}

3.按照List中对象的String类型的属性进行排序
1)方法一:
  /**
* 按照List中的某个String类型的属性进行排序
* @param list
*/
@SuppressWarnings("unchecked")
public static void sortStringMethod(List list){
Collections.sort(list, new Comparator(){
@Override
public int compare(Object o1, Object o2) {
Student stu1=(Student)o1;
Student stu2=(Student)o2;
return stu1.getName().compareTo(stu2.getName());
}
});
System.out.println("/////////////排序之后///////////////");
for(int i=0;i<list.size();i++){
Student st=(Student)list.get(i);
System.out.println("st.age="+st.getAge()+",st.name="+st.getName());
}
}

2)方法二:
  使用java.text.RuleBasedCollator来实现,用来执行区分语言环境的String 比较:
/**
* 按照List中的某个String类型的属性进行排序
* @param list
*/
@SuppressWarnings("unchecked")
public static void sortByRuleBasedCollator(List list){
Collections.sort(list, new Comparator(){
@Override
public int compare(Object o1, Object o2) {
return ((java.text.RuleBasedCollator)java.text.Collator.getInstance(java.util.Locale.CHINA)).compare(((Student)o1).getName(), ((Student)o2).getName());
}
});
System.out.println("/////////////排序之后///////////////");
for(int i=0;i<list.size();i++){
Student st=(Student)list.get(i);
System.out.println("st.age="+st.getAge()+",st.name="+st.getName());
}
}

4.测试排序的方法
        @SuppressWarnings("unchecked")
public static void main(String[] args) {

ArrayList list=new ArrayList();
Student t1=new Student();
t1.setAge(35);
t1.setName("wanglei");
list.add(t1);

Student t2=new Student();
t2.setAge(4);
t2.setName("lisi");
list.add(t2);

Student t3=new Student();
t3.setAge(56);
t3.setName("zhonghua");
list.add(t3);

Student t4=new Student();
t4.setAge(39);
t4.setName("waanglei");
list.add(t4);
System.out.println("/////////////排序之前///////////////");
for(int i=0;i<list.size();i++){
Student st=(Student)list.get(i);
System.out.println("st.age="+st.getAge()+",st.name="+st.getName());
}
//按照List中的某个Int类型的属性进行排序
sortIntMethod(list);
//按照List中的某个String类型的属性进行排序
sortStringMethod(list);
}

5.结果
1)按照List中对象的Int类型属性进行排序的结果:
 
list排序,根据list中存放对象的某一属性排序

2)按照按照List中对象的String类型的属性进行排序的结果:
 
list排序,根据list中存放对象的某一属性排序