如何从字符串数组或arraylist创建一个字符串？

使用

StringBuilder

String[] strings = {"Java", "is", "cool"};StringBuilder builder = new StringBuilder();for (String string : strings) {    if (builder.length() > 0) {        builder.append(" ");    }    builder.append(string);}String string = builder.toString();System.out.println(string); // Java is cool

或使用Apache Commons Lang

StringUtils#join()

String[] strings = {"Java", "is", "cool"};String string = StringUtils.join(strings, ' ');System.out.println(string); // Java is cool

或使用Java8的

Arrays#stream()

String[] strings = {"Java", "is", "cool"};String string = Arrays.stream(strings).collect(Collectors.joining(" "));System.out.println(string); // Java is cool