Java Collections unmodifiableSortedMap()
Java集合类的
unmodifiableSortedMap()方法用于获取不可修改的指定的排序图的视图。
语法
以下是
unmodifiableSortedMap()方法的声明:
public static <K,V> SortedMap<K,V> unmodifiableSortedMap(SortedMap<K,? extends V> m)
参数
| 参数 |
说明 |
必需/可选 |
| m |
这是要返回其不可修改视图的排序映射。 |
必需 |
返回
unmodifiableSortedMap()方法返回指定排序地图的不可修改视图。
异常
NA
示例1
import java.util.*;
public class CollectionsUnmodifiableSortedMapExample1 {
public static void main(String[] args) {
SortedMap<Integer, Integer> map = new TreeMap<Integer, Integer>();
map.put(1, 1001);
map.put(4, 1004);
map.put(2, 1002);
map.put(3, 1003);
System.out.println("Original Map: " + map);
SortedMap<Integer, Integer> map2 = Collections.unmodifiableSortedMap</span>(map);
map.put(5, 1005);
System.out.println("Unmodifiable Sorted Map: " + map2);
}
}
输出:
Original Map: {1=1001, 2=1002, 3=1003, 4=1004}
Unmodifiable Sorted Map: {1=1001, 2=1002, 3=1003, 4=1004, 5=1005}
示例2
import java.util.*;
public class CollectionsUnmodifiableSortedMapExample2 {
public static void main(String[] args) {
SortedMap<String, String> map = new TreeMap<String, String>();
map.put("1", "Whatsapp");
map.put("4", "Instagram");
map.put("3", "Facebook");
map.put("2", "Twitter");
System.out.println("Original Map: " + map);
SortedMap<String, String> map2 = Collections.unmodifiableSortedMap</span>(map);
map.put("5","Hangout");
System.out.println("Unmodifiable Sorted Map: " + map2);
}
}
输出:
Original Map: {1=Whatsapp, 2=Twitter, 3=Facebook, 4=Instagram}
Unmodifiable Sorted Map: {1=Whatsapp, 2=Twitter, 3=Facebook, 4=Instagram, 5=Hangout}
示例3
import java.util.*;
public class CollectionsUnmodifiableSortedMapExample3 {
public static void main(String[] args) {
SortedMap<Integer, String> map = new TreeMap<>();
map.put(1, "one");
map.put(2, "two");
System.out.println("Original Map: " + map);
SortedMap<Integer, String> map2 = Collections.unmodifiableSortedMap</span>(map);
map2.remove(1);
}
}
输出:
Original Map: {1=one, 2=two}
Exception in thread "main" java.lang.UnsupportedOperationException
at java.base/java.util.Collections$UnmodifiableMap.remove(Collections.java:1456)
at myPackage.CollectionsUnmodifiableSortedMapExample3.main(CollectionsUnmodifiableSortedMapExample3.java:10)
