Java实现HashMap排序方法的示例详解

package org.example.a;

import java.util.*;

public class Demo {

     public static void main(String[] args) {

         Map<String, String> map = new HashMap<>();

         map.put( "ad" , "dd" );

         map.put( "bc" , "ee" );

         map.put( "cb" , "ff" );

         for (Map.Entry<String, String> entry : map.entrySet()) {

             System.out.println(entry.getKey() + ":" + entry.getValue());

         }

         System.out.println();

         Map<String, String> linkedHashMap = new LinkedHashMap<>();

         // 默认按照升序排列

         map.entrySet().stream().sorted(Map.Entry测试数据paringByKey())

                 .forEach(o -> linkedHashMap.put(o.getKey(), o.getValue()));

         for (Map.Entry<String, String> entry : linkedHashMap.entrySet()) {

             System.out.println(entry.getKey() + ":" + entry.getValue());

         }

         System.out.println();

         Map<String, String> linkedHashMap1 = new LinkedHashMap<>();

         // 自定义排序（降序）

         map.entrySet().stream().sorted(Map.Entry测试数据paringByKey( new Comparator<String>() {

             @Override

             public int compare(String o1, String o2) {

                 return o2测试数据pareTo(o1);

             }

         })).forEach(o -> linkedHashMap1.put(o.getKey(), o.getValue()));

         for (Map.Entry<String, String> entry : linkedHashMap1.entrySet()) {

             System.out.println(entry.getKey() + ":" + entry.getValue());

         }

     }

}

package org.example.a;

import java.util.Comparator;

import java.util.HashMap;

import java.util.Map;

import java.util.TreeMap;

public class Demo {

     public static void main(String[] args) {

         Map<String, String> map = new HashMap<>();

         map.put( "ad" , "dd" );

         map.put( "bc" , "ee" );

         map.put( "cb" , "ff" );

         for (Map.Entry<String, String> entry : map.entrySet()) {

             System.out.println(entry.getKey() + ":" + entry.getValue());

         }

         System.out.println();

         // 默认按照升序排序

         Map<String, String> map1 = new TreeMap<>();

         map.forEach(map1::put);

         for (Map.Entry<String, String> entry : map1.entrySet()) {

             System.out.println(entry.getKey() + ":" + entry.getValue());

         }

         System.out.println();

         // 自定义排序（降序）

         Map<String, String> map2 = new TreeMap<>( new Comparator<String>() {

             @Override

             public int compare(String o1, String o2) {

                 return o2测试数据pareTo(o1);

             }

         });

         map.forEach(map2::put);

         for (Map.Entry<String, String> entry : map2.entrySet()) {

             System.out.println(entry.getKey() + ":" + entry.getValue());

         }

     }

}

package org.example.a;

import java.util.*;

public class Demo {

     public static void main(String[] args) {

         Map<String, String> map = new HashMap<>();

         map.put( "ad" , "dd" );

         map.put( "bc" , "ee" );

         map.put( "cb" , "ff" );

         for (Map.Entry<String, String> entry : map.entrySet()) {

             System.out.println(entry.getKey() + ":" + entry.getValue());

         }

         System.out.println();

         Map<String, String> linkedHashMap = new LinkedHashMap<>();

         // 默认按照升序排列

         map.entrySet().stream().sorted(Map.Entry测试数据paringByValue())

                 .forEach(o -> linkedHashMap.put(o.getKey(), o.getValue()));

         for (Map.Entry<String, String> entry : linkedHashMap.entrySet()) {

             System.out.println(entry.getKey() + ":" + entry.getValue());

         }

         System.out.println();

         Map<String, String> linkedHashMap1 = new LinkedHashMap<>();

         // 自定义排序（降序）

         map.entrySet().stream().sorted(Map.Entry测试数据paringByValue( new Comparator<String>() {

             @Override

             public int compare(String o1, String o2) {

                 return o2测试数据pareTo(o1);

             }

         })).forEach(o -> linkedHashMap1.put(o.getKey(), o.getValue()));

         for (Map.Entry<String, String> entry : linkedHashMap1.entrySet()) {

             System.out.println(entry.getKey() + ":" + entry.getValue());

         }

     }

}

package org.example.a;

import java.util.*;

public class Demo {

     public static void main(String[] args) {

         Map<String, String> map = new HashMap<>();

         map.put( "ad" , "dd" );

         map.put( "bc" , "ee" );

         map.put( "cb" , "ff" );

         for (Map.Entry<String, String> entry : map.entrySet()) {

             System.out.println(entry.getKey() + ":" + entry.getValue());

         }

         System.out.println();

         Map<String, String> sortedMap = new LinkedHashMap<>();

         List<Map.Entry<String, String>> entryList = new ArrayList<Map.Entry<String, String>>(

                 map.entrySet());

         Collections.sort(entryList, new Comparator<Map.Entry<String, String>>() {

             @Override

             public int compare(Map.Entry<String, String> me1, Map.Entry<String, String> me2) {

                 return me1.getValue()测试数据pareTo(me2.getValue());

             }

         });

         for (Map.Entry<String, String> stringStringEntry : entryList) {

             sortedMap.put(stringStringEntry.getKey(), stringStringEntry.getValue());

         }

         for (Map.Entry<String, String> entry : sortedMap.entrySet()) {

             System.out.println(entry.getKey() + ":" + entry.getValue());

         }

     }

}

package org.example.a;

import java.util.*;

public class Demo{

     public static List arrayList = new ArrayList();

     public static void main(String[] args) {

         Map<String, String> hashMap = new HashMap<String, String>();

         hashMap.put( "name1" , "josan1" );

         hashMap.put( "name2" , "josan2" );

         hashMap.put( "name3" , "josan3" );

         Set<Map.Entry<String, String>> set = hashMap.entrySet();

         Iterator<Map.Entry<String, String>> iterator = set.iterator();

         while (iterator.hasNext()) {

             Map.Entry entry = iterator.next();

             String key = (String) entry.getKey();

             String value = (String) entry.getValue();

             System.out.println( "key:" + key + ", value:" + value);

         }

     }

}

package org.example.a;

import java.util.*;

public class Demo{

     public static List arrayList = new ArrayList();

     public static void main(String[] args) {

         Map<String, String> hashMap = new LinkedHashMap<String, String>();

         hashMap.put( "name1" , "josan1" );

         hashMap.put( "name2" , "josan2" );

         hashMap.put( "name3" , "josan3" );

         Set<Map.Entry<String, String>> set = hashMap.entrySet();

         Iterator<Map.Entry<String, String>> iterator = set.iterator();

         while (iterator.hasNext()) {

             Map.Entry entry = iterator.next();

             String key = (String) entry.getKey();

             String value = (String) entry.getValue();

             System.out.println( "key:" + key + ", value:" + value);

         }

     }

}