首先,我们使用stringBuilder.append("List of strings:")语句将标题添加到字符串中。然后,我们使用一个for-each循环遍历stringList中的每个字符串,并通过stringBuilder.append()方法将每个字符串添加到输出字符串的新行中。 最后,我们使用System.out.println(stringBuilder.toString())语句将构建好的字符串打印出来。 运行...
*/@Testpublicvoidtest2(){actorList.stream()// 过滤演员年龄小于40的.filter(c->c.getAge()<40)// 用id进行排序.sorted(comparing(Actor::getId))// 合并map,拿到名字相同的去作用于各个演员.map(Actor::getName)// 转为list.collect(toList())// 输入.forEach(System.out::println);} 结果同样符合...
"木");list.add(2,"水");list.add(3,"超人强");list.add(4,"小呆呆");//集合中有“金”元素,返回索引位置 0System.out.println(list.indexOf("金"));//集合中没有“火”元素,返回 -1System.out.println(list.lastIndexOf("火"));print(list);//删除集合...
Java中对List集合的常用操作 其他 List中添加,获取,删除元素 List<String> person = new ArrayList<String>(); // 添加元素 person.add("A"); person.add("B"); person.add("C"); person.add("D"); System.out.print(person); // 删除元素 person.remove(2); person.remove("D"); System.out....
import java.util.*; public class PrintCollection { public static void main(String[] args) { printArray(); printList(); printSet(); printMap(); } public static void printArray(){ Object[] array=new Object[4]; array[0]=123; array[1]="hello"; array[2]=false; array[3]=new Date()...
import java.util.Scanner; public class PowerCalculator { public static void main(Strings) { // 创建 Scanner 对象以读取用户输入 Scanner scanner = new Scanner(System.in); // 提示用户输入一个数字 System.out.print("请输入一个数字: ");
(Arrays.asList(array2)); System.out.println("set:"+set); //将数组转成list集合 List<String> list_1=new ArrayList<String>(); for (int i = 0; i < array2.length; i++) { list_1.add(array2[i]); } System.out.println("list_1:"+list_1); String[] arrStrings2={"1","2",...
(a comma-separated list of strings) CodebaseEntry -> codebase (a string representation of a URL) PrincipalEntry -> OnePrincipal | OnePrincipal, PrincipalEntry OnePrincipal -> principal [ principal_class_name ] "principal_name" (a principal) PermissionEntry -> OnePermission | OnePermission ...
Formatting Numeric Print OutputEarlier you saw the use of the print and println methods for printing strings to standard output (System.out). Since all numbers can be converted to strings (as you will see later in this lesson), you can use these methods to print out an arbitrary mixture ...
converted to strings (as you will see later in this lesson), you can use these methods to print out an arbitrary mixture of strings and numbers. The Java programming language has other methods, however, that allow you to exercise much more control over your print output when numbers are ...