例如,我喜欢初始化一个类似[1,2,3,...,100]的集合.
通常,我们做如下:
for(int i = 1;i <= 100;i++ ){
set.add(i);
}
有没有方法可以更方便地做到这一点？
如 someMethod(startIndex, endIndex, step);
通过使用它,我们可以轻松地初始化[1,2,3,4,5]或[1,3,5,7,9]或其他集合.
假设我们有两个流如下:
IntStream stream1 = Arrays.stream(new int[] {13, 1, 3, 5, 7, 9});
IntStream stream2 = Arrays.stream(new int[] {1, 2, 6, 14, 8, 10, 12});
stream1.merge(stream2); // some method which is used to merge two streams.
是否有任何方便的方法使用Java 8流API将两个流合并到[13,1,2,3,5,6,7,8,9,10,12,14](顺序无关紧要) .或者我们只能同时处理一个流？
此外,如果两个流是对象流,如何只保留不同的对象,而不覆盖equals()和hashCode()方法？例如:
public class Student {
private String no;
private String name;
}
Student s1 = new Student("1", "May");
Student s2 = new Student("2", "Bob");
Student s3 = new Student("1", "Marry");
Stream<Student> stream1 = Stream.of(s1, s2);
Stream<Student> stream2 = …我从http://maven.springframework.org/release/org/springframework/spring/下载了spring-framework-4.1.6.RELEASE
然后我跟随Spring网站http://spring.io/guides/gs/rest-service/开始一个项目,但我发现它有一个问题.
//The import org.springframework.boot cannot be resolved
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
好像它找不到jar文件所以无法导入它,但我已经添加了所有jar文件来构建路径.
我该如何解决？Spring和SpringFramework是一样的吗？
我在jdk8中找到了HashMap函数resize()的源代码:
final Node<K,V>[] resize() {
Node<K,V>[] oldTab = table;
int oldCap = (oldTab == null) ? 0 : oldTab.length;
int oldThr = threshold;
int newCap, newThr = 0;
if (oldCap > 0) {
if (oldCap >= MAXIMUM_CAPACITY) {
threshold = Integer.MAX_VALUE;
return oldTab;
}
else if ((newCap = oldCap << 1) < MAXIMUM_CAPACITY &&
oldCap >= DEFAULT_INITIAL_CAPACITY)
newThr = oldThr << 1; // double threshold
}
else if (oldThr > 0) // initial capacity was placed in threshold
newCap = …