public static void main(String[] args) {
Stu stu1 = new Stu("张三",18);
Stu stu2 = new Stu("李四",18);
Stu stu3 = new Stu("王五",18);
List<Stu> list = new ArrayList<Stu>();
list.add(stu1);
list.add(stu2);
list.add(stu3);
String loopJoint = loopJointDESC(list, list.size());
System.out.println(loopJoint);
* 实现学生集合的姓名拼接:name1|name2|nameN
* @param list
* @param size 控制递归次数(size=list.size())
* @return
public static String loopJointDESC(List<Stu> list,int size ) {
if(list.size()<=0) return null;
if(size==1) return list.get(0).getName();
String joinStr = "|";
size--;//下标值和递归次数减少1
String name = list.get(size).getName();
String loopJoint = loopJointDESC(list, size);
return name+joinStr+loopJoint;
public class Stu {
private String name;
private Integer age;
public String getName() {
return name;
public void setName(String name) {
this.name = name;
public Integer getAge() {
return age;
public void setAge(Integer age) {
this.age = age;
public Stu(String name, Integer age) {
super();
this.name = name;
this.age = age;
public Stu() {
super();
发现反过来拼接了,于是改为
public static String loopJointASC(List<Stu> list,int size ) {
if(list.size()<=0) return null;
if(size==1) return list.get(list.size()-1).getName();
String joinStr = "|";
String name = list.get(list.size()-size).getName();
size--;//下标值和递归次数减少1
String loopJoint = loopJointASC(list, size);
return name+joinStr+loopJoint;
分隔符 “|” 可自己定义也可以删除。
最后留下两个问题:
当list非常大的时候,使用for 循环和递归哪种实现方式的速度更快呢?
双层for 循环改为,for循环+递归性能会不会更好呢?
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