尝试重写toString()方法，因为您希望元素将被打印。 打印的方法可以是这样的:

for(int i=0;i<list.size();i++){
    System.out.println(list.get(i).toString());
} 

    list.stream().map(x -> x.getName()).forEach(System.out::println);

You haven't specified what kind of elements the list contains, if it is a primitive data type then you can print out the elements. But if the elements are objects then as Kshitij Mehta mentioned you need to implement (override) the method "toString" within that object - if it is not already implemented - and let it return something meaning full from within the object, example: class Person { private String firstName; private String lastName; @Override public String toString() { return this.firstName + " " + this.lastName; } }

   List<String> textList=  messageList.stream()
                            .map(Message::getText)
                            .collect(Collectors.toList());

        textList.stream().forEach(System.out::println);
        public class Message  {

        String name;
        String text;

        public Message(String name, String text) {
            this.name = name;
            this.text = text;
        }

        public String getName() {
            return name;
        }

      public String getText() {
        return text;
     }
   }

我写了一个转储函数，它基本上打印出对象的公共成员，如果它没有覆盖toString()。可以很容易地将其扩展为调用getter。 Javadoc:

将给定对象转储到系统。Out，使用以下规则: 如果对象是Iterable，则它的所有组件都将被转储。 如果Object或它的一个超类覆盖了toString()，则“toString”将被转储 否则，该方法将为对象的所有公共成员递归调用

/**
 * Dumps an given Object to System.out, using the following rules:<br>
 * <ul>
 * <li> If the Object is {@link Iterable}, all of its components are dumped.</li>
 * <li> If the Object or one of its superclasses overrides {@link #toString()}, the "toString" is dumped</li>
 * <li> Else the method is called recursively for all public members of the Object </li>
 * </ul>
 * @param input
 * @throws Exception
 */
public static void dump(Object input) throws Exception{
    dump(input, 0);
}

private static void dump(Object input, int depth) throws Exception{
    if(input==null){
        System.out.print("null\n"+indent(depth));
        return;
    }

    Class<? extends Object> clazz = input.getClass();
    System.out.print(clazz.getSimpleName()+" ");
    if(input instanceof Iterable<?>){
        for(Object o: ((Iterable<?>)input)){
            System.out.print("\n"+indent(depth+1));
            dump(o, depth+1);
        }
    }else if(clazz.getMethod("toString").getDeclaringClass().equals(Object.class)){
        Field[] fields = clazz.getFields();
        if(fields.length == 0){
            System.out.print(input+"\n"+indent(depth));
        }
        System.out.print("\n"+indent(depth+1));
        for(Field field: fields){
            Object o = field.get(input);
            String s = "|- "+field.getName()+": ";
            System.out.print(s);
            dump(o, depth+1);
        }
    }else{

        System.out.print(input+"\n"+indent(depth));
    }
}

private static String indent(int depth) {
    StringBuilder sb = new StringBuilder();
    for(int i=0; i<depth; i++)
        sb.append("  ");
    return sb.toString();
}

你可以试试:

2D(或以上) System.out.println (Arrays.deepToString (list.toArray ())); 1 d System.out.println (Arrays.toString (list.toArray ()))