StringJoiner 小练习之二

`import java.util.StringJoiner;
public class Demo13{
public static void main(String[] args) {

	String[] names = {"Bob", "Alice", "Grace"};
	
	
	//数组元素间用分隔符"," 打印出来Hello Bob, Alice, Grace !
	
	//这是一个重载构造器，第一个参数表示分隔符，第二个参数表示开头，第三个参数表示结尾

	StringJoiner sj = new StringJoiner(", ","Hello "," ！");
	
	for(String name:names){
		sj.add(name);
	}
	
	System.out.println(sj.toString());

}

}`