Java示例只读集合 Java示例打印集合 Java示例集合删除 Java示例只读集合 import java.util.ArrayList; import java.util.Arrays; import java.util.Collections; import java.util.HashMap; import java.util.HashSet; import java.util.List; import java.util.Map; import java.util.Set; public class Main { public static void main(String[] argv) throws Exception { List stuff = Arrays.asList(new String[] { "a", "b" }); List list = new ArrayList(stuff); list = Collections.unmodifiableList(list); try { list.set(0, "new value"); } catch (UnsupportedOperationException e) { } Set set = new HashSet(stuff); set = Collections.unmodifiableSet(set); Map map = new HashMap(); map = Collections.unmodifiableMap(map); System.out.println("Collection is read-only now."); } } Java示例打印集合 Java示例集合删除