Here you can find the source of joinColumnArray(List
public static String joinColumnArray(List<String> columnArray)
//package com.java2s; /**/*from w w w. j av a 2 s . c o m*/ * Copyright 2011-2016 Asakusa Framework Team. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import java.util.List; public class Main { public static String joinColumnArray(List<String> columnArray) { if (columnArray == null || columnArray.size() == 0) { return null; } StringBuilder column = new StringBuilder(); int columnSize = columnArray.size(); for (int i = 0; i < columnSize; i++) { column.append(columnArray.get(i)); if (i + 1 < columnSize) { column.append(","); } } return column.toString(); } }