Java Collections checkedNavigableSet()
checkedNavigableSet()是Java Collections 类的内置方法。此方法用于获取指定的导航集的动态类型安全视图。如果尝试插入值类型错误的元素，则将通过立即ClassCastException进行插入。
语法
以下是
checkedNavigableSet()方法的声明:
public static <E> NavigableSet<E> checkedNavigableSet(NavigableSet<E> s, Class<E> type)
参数
| 参数 |
说明 |
必需/可选 |
| s |
这是要为其返回动态类型安全视图的导航集。 |
必需 |
| type |
这是允许s保留的元素的类型。 |
必需 |
返回
checkedNavigableSet()方法返回指定导航集的动态类型安全视图。
异常
ClassCastException
兼容版本
Java 1.8及更高版本
示例1
import java.util.*;
public class CollectionsCheckedNavigableSetExample1 {
public static void main(String[] args) {
NavigableSet<String> set = new TreeSet<>();
//Insert values in the Map
set.add("A1");
set.add("B2");
set.add("C3");
set.add("D4");
//Create type safe view of the Set
System.out.println("Type safe view of the Navigable Set is: "+Collections.checkedNavigableSet(set,String.class));
}
}
输出:
Type safe view of the Navigable Set is: [A1, B2, C3, D4]
示例2
import java.util.*;
public class CollectionsCheckedNavigableSetExample2 {
public static void main(String[] args) {
NavigableSet<Integer> set = new TreeSet<>();
//Insert values in the Map
set.add(11);
set.add(22);
set.add(33);
set.add(44);
//Create type safe view of the Set
NavigableSet<Integer> TypeSafeSet;
TypeSafeSet = Collections.checkedNavigableSet(set,Integer.class);
System.out.println("The view of the Navigable Set is: "+TypeSafeSet);
}
}
输出:
The view of the Navigable Set is: [11, 22, 33, 44]
示例3
import java.util.*;
public class CollectionsCheckedNavigableSetExample3 {
public static void main(String[] args) {
NavigableSet<String> set = new TreeSet<>();
//Insert values in the Map
set.add("A");
set.add("B");
set.add("A");
set.add("B");
System.out.println("Type safe view of the Navigable Set1 is: "+Collections.checkedNavigableSet(set,String.class));
NavigableSet<Integer> sset = new TreeSet<>();
sset.add(11);
sset.add(12);
sset.add(11);
sset.add(12);
//Create type safe view of the Map
System.out.println("Type safe view of the Navigable Set2 is: "+Collections.checkedNavigableSet(sset,Integer.class));
Set sset2 = sset;
sset2.add("two");
System.out.println("TypeSafe View: "+sset2);
}
}
输出:
Type safe view of the Navigable Set1 is: [A, B]
Type safe view of the Navigable Set2 is: [11, 12]
Exception in thread "main" java.lang.ClassCastException: java.base/java.lang.Integer cannot be cast to java.base/java.lang.String
at java.base/java.lang.String.compareTo(String.java:124)
at java.base/java.util.TreeMap.put(TreeMap.java:566)
at java.base/java.util.TreeSet.add(TreeSet.java:255)
at myPackage.CollectionCheckedNavigableSetExample3.main(CollectionCheckedNavigableSetExample3.java:21)
