public class JoinerTest { public static void main(String args[]){ //1、将list字符串集合,以,形式转为字符串 List<String> list =new ArrayList<String>(); list.add("xx"); list.add("zz"); list.add("dd"); //Joiner.on(",")获得Joiner实例对象 Joiner joiner = Joiner.on(","); //joiner.join(list)传入操作的集合,并转成字符串格式 System.out.println(joiner.join(list)); //输出结果:xx,zz,dd //2、将Iterator<T>列表,转为字符串 Iterator<String> it=list.iterator(); String str=Joiner.on("|").join(it); System.out.println(str); //输出结果:xx|zz|dd //3、连接多个字符串 String str1=Joiner.on(",").join("小小","爸爸","妈妈","爷爷","奶奶"); System.out.println(str1); //输出:小小,爸爸,妈妈,爷爷,奶奶 //4、连接字符串与列表 StringBuilder builder=new StringBuilder("小小最乖"); //返回StringBuilder类型 StringBuilder str2=Joiner.on(",").appendTo(builder,list); System.out.println(str2); //输出:小小最乖xx,zz,dd //5、跳过null值连接 list.add(null); list.add("小小"); //skipNulls()代表去除null String str3=Joiner.on(",").skipNulls().join(list); System.out.println(str3); //输出:xx,zz,dd,小小 //6、替换null值进行连接 String str4=Joiner.on(",").useForNull("空").join(list); System.out.println(str4); //输出:xx,zz,dd,空,小小 //7、Map的键值对打印出来 Map<String, String> map = new HashMap<>(); map.put("key1", "value1"); map.put("key2", "value2"); map.put("key3", "value3"); Joiner.MapJoiner mapJoiner = Joiner.on(",").withKeyValueSeparator("="); System.out.println(mapJoiner.join(map)); //输出:key1=value1,key2=value2,key3=value3 //8、一步将字符串转为List<Long>集合(前面先转为list<String>,后面用java8特性将List<String>转为List<Long>) List<Long> list=Splitter.on("#").splitToList("111#222#333").stream().mapToLong(str->Long.parseLong(str)).boxed().distinct().collect(Collectors.toList()); } }