/** * list转换为字符串 */  @Test  public void joinTest(){  List<String> names = Lists.newArrayList("John", "Jane", "Adam", "Tom");  String result = Joiner.on(",").join(names);  assertEquals(result, "John,Jane,Adam,Tom");  }  /** * map转换为字符串 */  @Test  public void whenConvertMapToString_thenConverted() {  Map<String, Integer> salary = Maps.newHashMap();  salary.put("John", 1000);  salary.put("Jane", 1500);  String result = Joiner.on(" , ").withKeyValueSeparator(" = ")  .join(salary);  System.out.println(result);  }  /** * list转String，跳过null */  @Test  public void whenConvertListToStringAndSkipNull_thenConverted() {  List<String> names = Lists.newArrayList("John", null, "Jane", "Adam", "Tom");  String result = Joiner.on(",").skipNulls().join(names);  System.out.println(result);  assertEquals(result, "John,Jane,Adam,Tom");  }  /** * list转String，将null变成其他值 */  @Test  public void whenUseForNull_thenUsed() {  List<String> names = Lists.newArrayList("John", null, "Jane", "Adam", "Tom");  String result = Joiner.on(",").useForNull("nameless").join(names);  System.out.println(result);  assertEquals(result, "John,nameless,Jane,Adam,Tom");  }  /** * String to List */  @Test  public void whenCreateListFromString_thenCreated() {  String input = "apple - banana - orange";  List<String> result = Splitter.on("-").trimResults().splitToList(input);  System.out.println(result);  //assertThat(result, contains("apple", "banana", "orange"));  }  /** * String to Map */  @Test  public void whenCreateMapFromString_thenCreated() {  String input = "John=first,Adam=second";  Map<String, String> result = Splitter.on(",")  .withKeyValueSeparator("=")  .split(input);  assertEquals("first", result.get("John"));  assertEquals("second", result.get("Adam"));  }  /** * 多个字符进行分割 */  @Test  public void whenSplitStringOnMultipleSeparator_thenSplit() {  String input = "apple.banana,,orange,,.";  List<String> result = Splitter.onPattern("[.|,]")  .omitEmptyStrings()  .splitToList(input);  System.out.println(result);  }  /** * 每隔多少字符进行分割 */  @Test  public void whenSplitStringOnSpecificLength_thenSplit() {  String input = "Hello world";  List<String> result = Splitter.fixedLength(3).splitToList(input);  System.out.println(result);  }  /** * 限制分割多少字后停止 */  @Test  public void whenLimitSplitting_thenLimited() {  String input = "a,b,c,d,e";  List<String> result = Splitter.on(",")  .limit(4)  .splitToList(input);  assertEquals(4, result.size());  System.out.println(result);  }