Java8优雅的字符串拼接工具类StringJoiner实例代码

		String a = "w", b = "d", c = "n", d = "m", e = "d";
  List<String> list = new ArrayList<>();
  list.add(a);
  list.add(b);
  list.add(c);
  list.add(d);
  list.add(e);

	
		String result = "";
  for (String str : list) {
   result += str + ".";
  }
  // 最后在处理掉最后一个 “.” 齐活儿，收工
  System.err.println(result.substring(0, result.length() - 1));
  

	
		StringBuilder builder = new StringBuilder();
  list.forEach(str -> builder.append(str).append("."));
  System.err.println(builder.toString().substring(0, builder.length() - 1));
  

	
  // 声明StringJoiner, 每个元素通过 "." 分割 		
  StringJoiner joiner = new StringJoiner(".");
  list.forEach(joiner::add);
  System.err.println(joiner.toString());
  

  // 每个元素通过 "." 分割，并且用 "[" 和 "]" 包住前后 		
  StringJoiner joiner2 = new StringJoiner(".", "[", "]");
  list.forEach(joiner2::add);
  System.err.println(joiner2.toString());
  

  // 每个元素通过 "." 分割，并且用 "[" 和 "]" 包住前后 		
  StringJoiner joiner2 = new StringJoiner(".", "[", "]");
  list.forEach(joiner2::add);
  // 将joner和joner2的元素合并，并且每个元素通过 "." 分割，并且用 "[" 和 "]" 包住前后 
  joiner2.merge(joiner);
  System.err.println(joiner2.toString());
  

		StringJoiner joiner = new StringJoiner(".");
  list.forEach(joiner::add);
  System.err.println(joiner.toString());
  joiner.setEmptyValue("abc");
  System.err.println(joiner.toString());