import java.util.ArrayList;
import java.util.List;

public class StringBuilderDemo1 {

    public static String join(String join,String[] strAry){
        StringBuffer sb=new StringBuffer();
        for(int i=0;i<strAry.length;i++){
             if(i==(strAry.length-1)){
                 sb.append(strAry[i]);
             }else{
                 sb.append(strAry[i]).append(join);
             }
        }
       
        return new String(sb);
    }

    public static void main(String[] args){

        String[] sa={"a","b","c"};
        String s1=StringBuilderDemo1.join("-",sa);
        System.out.println(s1);

    }
}

------解决方案--------------------
Apache Commons组件中有一个commons-lang.jar，用StringUtils.join(array, "-")就可以了，我经常用