使用 Collection 类的 Collections.unmodifiableList() 方法来设置集合为只读

完整代码

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", "c" });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("集合只读设置完成！");}
}

结果输出

集合只读设置完成！