如何在外部循环中从[0到9]访问字符串列表？

Question

I am trying to write a code that allows me to access String msgbody and place it in an email. However, using the following code only the final String shows up outside the for loop. I searched many times for an answer, and am a bit new to Java.

    List<String> urls = new ArrayList<String>();
    String msgbody = "";
       for (int i = 0; i < urls.size(); i++) {
            //urls.get(i); unecessary
            // String msgbody0; - Used to attempt msgbody0 = url.get(i); then msgbody += msgbody0; but only prints first url
            int sum = i + 1;
            for (j = 1; j < 2 ; j++)
            {
                msgbody = urls.get(i);

                //urls.add(msgbody); not needed
                System.out.print("("+ sum +")" +"");
                System.out.println(msgbody); 
            }
            if(i==9){
                break;
            }
        } // Inside the for loop everything prints properly.

       System.out.println(msgbody); // How can i replicate it here?(Outside for loop)

Edit: THIS worked: (Initially -The following only shows the first link repeatedly:) I changed from Java to Java EE and it worked? What was i missing?

    msgbody += urls.get(i);

I can make it work without the for loop, but its sloppy.

Answer 1

You could change msgbody = urls.get(i); to msgbody += urls.get(i); (otherwise you're completely replacing the msgbody with each iteration). Also, I would prefer a StringBuilder , the diamond operator <> and a for-each loop . Like,

List<String> urls = new ArrayList<>();
StringBuilder sb = new StringBuilder();
for (String url : urls) {
    sb.append(urls.get(url));
}
System.out.println(sb);

Answer 2

only the minor change is that you are replacing msgbody rather than to concatenate it.

List<String> urls = new ArrayList<String>();
    String msgbody = "";
       for (int i = 0; i < urls.size(); i++) {
            //urls.get(i); unecessary
            // String msgbody0; - Used to attempt msgbody0 = url.get(i); then msgbody += msgbody0; but only prints first url
            int sum = i + 1;
            for (j = 1; j < 2 ; j++)
            {
                msgbody += urls.get(i);

                urls.add(msgbody);
                System.out.print("("+ sum +")" +"");
                System.out.println(msgbody); 
            }
            if(i==9){
                break;
            }
        } // Inside the for loop everything prints properly.

       System.out.println(msgbody);