public class test48 {//连接字符串public static String concatString(String base,String[] str){StringBuilder builder=new StringBuilder(base);//构建可变字符串for(String s:str){builder.append(" "+s);}return  builder.toString();}//删除空格public static String deleteSpace(String target){while(target.contains(" ")){StringBuilder builder=new StringBuilder(target);int index=builder.indexOf(" ");builder.deleteCharAt(index);target=builder.toString();}return target;}
}

测试类

//stringbuilder
public class test49 {public static void main(String[] args){StringBuilder builder=new StringBuilder("我是一个热血的少年");//System.out.println(builder);String str="今天会下雨吗";String[] strs={"会的","也许会的","谁知道呢"};String str1=test48.concatString(str,strs);System.out.println(str1);String str3="我 是 歌谣";//test48.deleteSpace(str3);String str4=test48.deleteSpace(str3);System.out.println(str4);}
}