每日日报

今天看网课

1）StingBuilder和StringJoiner

package liuer;
import java.util.StringJoiner;

public class StringBuilderDemo {
public static void main(String[] args){
StringBuilder sb=new StringBuilder();
sb.append(52);
sb.append(1).append("中国");
System.out.println(sb.toString());
int[] arr=new int[]{12,24,35,46};
StringJoiner sj=new StringJoiner(", ","[","]");
for(int x:arr){
sj.add(Integer.toString(x));
}
System.out.println(sj.toString());
}
}

2)Intege

package liuer;

public class IntegerDemo {
public static void main(String[] args){
Integer a=12;
System.out.print(a.valueOf(a));
}

}