import java.util.StringJoiner;public class StringJoinTest {    public static void main(String[] args) {        String[] fields = { "name", "position", "salary" };        String table = "employee";        String select = buildSelectSql(table, fields);        System.out.println(select);        System.out.println("SELECT name, position, salary FROM employee".equals(select) ? "测试成功" : "测试失败");    }    static String buildSelectSql(String table, String[] fields) {        // TODO:        StringJoiner joiner = new StringJoiner(", ", "SELECT ", " FROM " + table);        for (String str:fields) {            joiner.add(str);        }        return joiner.toString();    }}