Java中利⽤Collections.sort（）⽅法根据对象集合中的字符串字段排序（包
param name含。。。
说明：
使⽤java中的Collections.sort()⽅法进⾏排序，主要部分在于实现的StrComparatorUtils根据集合中对象的字符串类型字段进⾏排序。
主要是解决字符串中即包含字母⼜包含字符串的情况下，排序不准确的问题。
1、测试⽅法
public class SortTest {
public static void main(String[] args){
List<SortDto> sortDtoList =new ArrayList<>();
sortDtoList.add(new SortDto("a2hang",1));
sortDtoList.add(new SortDto("d1",1));
sortDtoList.add(new SortDto());
sortDtoList.add(new SortDto("1d",1));
// 主要⽅法就是StrComparatorUtils类
// 传⼊的参数中"name"为需要排序的字段名称(必须是字符串类型)，第⼆个参数是“是否倒叙排列”
Collections.sort(sortDtoList,new StrComparatorUtils("name",false));
for(SortDto sortDto : sortDtoList){
System.out.String());
}
}
}
输出结果
SortDomain{name='null', age=null}
SortDomain{name='1d', age=1}
SortDomain{name='a2hang', age=1}
SortDomain{name='d1', age=1}
2、字符串⽐较⼯具类
/**
* 根据传⼊类的属性进⾏排序
* 说明：属性必须是字符串类型
*/
public class StrComparatorUtils<T>implements Comparator<T>{
private String str1, str2;
private int pos1, pos2, len1, len2;
// 传⼊类中需要⽐较的字段
private String propertyName;
private boolean isDesc =false;
/**
* 传⼊对象的属性名，根据该属性值进⾏排序
* @param propertyName
*/
public StrComparatorUtils(String propertyName){
this.propertyName = propertyName;
}
/
**
* 传⼊对象的属性名，根据该属性值进⾏排序
* @param propertyName
* @param isDesc 是否倒序，默认为false
*/
public StrComparatorUtils(String propertyName,boolean isDesc){
this.propertyName = propertyName;
this.propertyName = propertyName;
this.isDesc = isDesc;
}
public int compare(T o1, T o2){
if(isDesc){
str2 =getPropertyValue(o1);
str1 =getPropertyValue(o2);
}else{
str1 =getPropertyValue(o1);
str2 =getPropertyValue(o2);
}
len1 = str1.length();
len2 = str2.length();
pos1 = pos2 =0;
int result =0;
while(result ==0&& pos1 < len1 && pos2 < len2){
char ch1 = str1.charAt(pos1);
char ch2 = str2.charAt(pos2);
if(Character.isDigit(ch1)){
result = Character.isDigit(ch2)?compareNumbers():-1;
}else if(Character.isLetter(ch1)){
result = Character.isLetter(ch2)?compareOther(true):1;
}else{
result = Character.isDigit(ch2)?1
: Character.isLetter(ch2)?-1
:compareOther(false);
}
pos1++;
pos2++;
}
return result ==0? len1 - len2 : result;
}
private String getPropertyValue(T o1){
String str ="";
try{
Field field = o1.getClass().getDeclaredField(propertyName);            field.setAccessible(true);
Object obj = (o1);
if(obj != null){
String();
}
}catch(Exception e){
e.printStackTrace();
}
return str;
}
private int compareNumbers(){
int end1 = pos1 +1;
while(end1 < len1 && Character.isDigit(str1.charAt(end1))){            end1++;
}
int fullLen1 = end1 - pos1;
while(pos1 < end1 && str1.charAt(pos1)=='0'){
pos1++;
}
int end2 = pos2 +1;
while(end2 < len2 && Character.isDigit(str2.charAt(end2))){            end2++;
}
}
int fullLen2 = end2 - pos2;
while(pos2 < end2 && str2.charAt(pos2)=='0'){
pos2++;
}
int delta =(end1 - pos1)-(end2 - pos2);
if(delta !=0){
return delta;
}
while(pos1 < end1 && pos2 < end2){
delta = str1.charAt(pos1++)- str2.charAt(pos2++);
if(delta !=0){
return delta;
}
}
pos1--;
pos2--;
return fullLen2 - fullLen1;
}
private int compareOther(boolean isLetters){
char ch1 = str1.charAt(pos1);
char ch2 = str2.charAt(pos2);
if(ch1 == ch2){
return0;
}
if(isLetters){
ch1 = UpperCase(ch1);
ch2 = UpperCase(ch2);
if(ch1 != ch2){
ch1 = LowerCase(ch1);
ch2 = LowerCase(ch2);
}
}
return ch1 - ch2;
}
}
3、测试实体类
public class SortDto {
private String name;
private Integer age;
public SortDto(){
}
public SortDto(String name,int age){
this.name = name;
this.age = 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;
}
@Override
public String toString(){
return"SortDomain{"+
"name='"+ name +'\''+
", age="+ age +
'}';
}
}

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