java实现中文汉字的首字母排序
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java中可以排序的工具类和接口共有五个SortedMap 、SortedSet、TreeMap 、TreeSet和Collections,Collections中需要显式调用sort()方法。
- import
java.util.List; - import
java.util.ArrayList; - import
java.util.Arrays; - import
java.util.Collections; - import
myUtil.myArrayComparator; - import
java.util.Map; - import
java.util.HashMap; - import
java.util.TreeMap; - import
java.util.Collection; - import
java.util.Iterator; - import
myUtil.myMapComparator; -
- public
class mySort { -
public mySort() { -
} -
-
-
public void arraySort() { -
-
String[] sortArray = {"中山", "汕尾", "广州", "汕头", "阳江"}; -
Arrays.sort(sortArray); -
for ( inti 0;= i 5;< i++) { -
System.out.println( (String) sortArray[i]); -
}
-
String[]
reverseArray "中山",= { "汕尾", "广州", "汕头", "阳江"}; -
Collections.reverse(Arrays.asList(reverseArray)); -
for ( inti 0;= i 5;< i++) { -
System.out.println( (String) reverseArray[i]); -
}
- import
java.text.Collator; - import
java.util.Arrays; - import
java.util.Comparator; - public
class test { -
-
public static void main(String[] args) { -
// TODO Auto-generated method stub -
Comparator -
String[] newArray={"中山","汕头","广州","安庆","阳江","南京","武汉","北京","安阳","北方"}; -
Arrays.sort(newArray,com); -
for(String i:newArray){ -
System.out.print(i+" );" -
} -
} - }
- public
void listSort(){ -
List sortList=new ArrayList(); -
sortList.add("中山"); -
sortList.add("汕尾"); -
sortList.add("广州"); -
sortList.add("汕头"); -
sortList.add("阳江"); -
-
myArrayComparator comparator = new myArrayComparator(); -
Collections.sort(sortList,comparator); -
for(int i= 0;i -
//因为ArrayList实现的是RandomAccess 随机访问接口。使用get()要比迭代的效率高。 -
//如果实现的是SequenceAccess(顺序访问接口。如:LinkList),使用迭代的效率高。 -
System.out.println(sortList.get(i)); -
}
-
Object[]
listToArray=sortList.toArray(); -
Arrays.sort(listToArray, comparator); -
for ( inti 0;= i < listToArray.length; i++) { -
System.out.println( (String) listToArray[i]); -
}
- public
void mapSort(){ -
// 按照键值排序 -
myArrayComparator comparator = new myArrayComparator(); -
Map sortMap= new TreeMap(comparator); -
sortMap.put("中山", "a"); -
sortMap.put("广州", "b"); -
sortMap.put("潮州", "c"); -
//注意:每次对TreeMap进行put()时,TreeMap都会自动调用它的compare(key,Entry.key) -
//按照key进行排序 -
Collection col = sortMap.keySet(); -
Iterator it = col.iterator(); -
while (it.hasNext()) { -
System.out.println(it.next()); -
} -
-
}
}
//重写compare方法
- package
myUtil; - import
java.util.Comparator; - import
java.text.Collator; - import
java.text.CollationKey; -
- public
class myComparator implementsComparator { -
-
//关于Collator。 -
private Collator //点击查看中文api详解collator = Collator.getInstance(); -
-
public myComparator() { -
} -
-
-
-
public int compare(Object o1, Object o2) { -
-
//把字符串转换为一系列比特,它们可以以比特形式与 CollationKeys 相比较 -
CollationKey key1=collator.getCollationKey(o1.toString());//要想不区分大小写进行比较用o1.toString().toLowerCase() -
CollationKey key2=collator.getCollationKey(o2.toString()); -
-
return key1.compareTo(key2); //返回的分别为1,0,-1分别代表大于,等于,小于。要想按照字母降序排序的话 加个“-”号 -
} - }

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