How can I get multiple Strings from an ArrayList in a simplified way and merge into just one string variable? I'm new to Java and I'm having trouble completing this change in a simplified way, avoiding long, unnecessary lines of code.
List<String> fields_list = new ArrayList<String>();
Saída: ["Campo1, Campo2, Campo3"]
This should be my String variable:
String fields = "Campo1 Campo2 Campo3";
Use the join () of the String class:
String fields = String.join(" ", fields_list);
Note: Requires JAVA 8
Use StringBuilder to group your values and for iterate over the list, for example:
StringBuilder sb = new StringBuilder();
for (String s : fields_list)
{
sb.append(s);
sb.append(" ");
}
System.out.println(sb.toString().trim());
s1 + s2
In this way, for each concatenated one, the compiler generates a new instance of StringBuilder implicitly, so the best way is to use only 1 as the example.
Or you can loop:
String listString;
for (String s : list)
{
listString += s + " ";
}
Or you can use StringUtils, which is located in commons -lag
listString = StringUtils.join(list, " ");