我有一个包含国家名称的List<String>对象。我如何按字母顺序对这个列表排序?


当前回答

Java 8,

countries.sort((country1, country2) -> country1.compareTo(country2));

如果String的compareTo不适合您的需要,您可以提供任何其他比较器。

其他回答

下行字母:

List<String> list;
...
Collections.sort(list);
Collections.reverse(list);

你可以使用下面这行

集合。排序(listOfCountryNames String.CASE_INSENSITIVE_ORDER)

它类似于Thilo的建议,但不会区分大小写字符。

//Here is sorted List alphabetically with syncronized
package com.mnas.technology.automation.utility;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;

import org.apache.log4j.Logger;
/**
* 
* @author manoj.kumar
*/
public class SynchronizedArrayList {
static Logger log = Logger.getLogger(SynchronizedArrayList.class.getName());
@SuppressWarnings("unchecked")
public static void main(String[] args) {

List<Employee> synchronizedList = Collections.synchronizedList(new ArrayList<Employee>());
synchronizedList.add(new Employee("Aditya"));
synchronizedList.add(new Employee("Siddharth"));
synchronizedList.add(new Employee("Manoj"));
Collections.sort(synchronizedList, new Comparator() {
public int compare(Object synchronizedListOne, Object synchronizedListTwo) {
//use instanceof to verify the references are indeed of the type in question
return ((Employee)synchronizedListOne).name
.compareTo(((Employee)synchronizedListTwo).name);
}
}); 
/*for( Employee sd : synchronizedList) {
log.info("Sorted Synchronized Array List..."+sd.name);
}*/

// when iterating over a synchronized list, we need to synchronize access to the synchronized list
synchronized (synchronizedList) {
Iterator<Employee> iterator = synchronizedList.iterator();
while (iterator.hasNext()) {
log.info("Sorted Synchronized Array List Items: " + iterator.next().name);
}
}

}
}
class Employee {
String name;
Employee (String name) {
this.name = name;

}
}

在一行中,使用Java 8:

list.sort(Comparator.naturalOrder());

JAVA 8相同:-

//Assecnding order
        listOfCountryNames.stream().sorted().forEach((x) -> System.out.println(x));

//Decending order
        listOfCountryNames.stream().sorted((o1, o2) -> o2.compareTo(o1)).forEach((x) -> System.out.println(x));