关于@Value注入List,Map及设置默认值问题

populate:
  string: stringValue

    @Value("${populate.string2:}")	// 默认值是空字符串“”
    private String stringV;
    
    @Value("${populate.string:null}")	// 默认值是null
    private String stringV2;
    
    @Value("${populate.string:defaultValue}")	// 默认值是“defaultValue”
    private String stringV3;

populate:
  array: array1,array2,array3

    @Value("${populate.array:}") // 默认值是[]
    private String[] array;
    
    @Value("${populate.array:a1,a2,a3}") // 默认值是[a1,a2,a3]
    private String[] array1;

populate:
  list: list1,list2,list3

    @Value("${populate.list:}")  // 默认值是空List，{}
    private List<String> list0;

    @Value("#{'${populate.list:}'.split(',')}") // 默认值是包含一个空字符串的List {“”}
    private List<String> list1;

    @Value("${populate.list:l1,l2,l3}")  // 默认值是{l1,l2,l3}
    private List<String> list2;
    
    @Value("#{'${populate.list:l1,l2,l3}'.split(',')}") // 默认值是{l1,l2,l3}
    private List<String> list3;
    
    @Value("#{'${populate.list:,}'.split(',')}") // 默认值是空List，{}
    private List<String> list4;

populate:
  map: "{
         'key1': 'value1',
         'key2': 'value2',
         'key3': 'value3'
         }"
         
  mapList: "{
          key1: 'v11,v12',
          key2: 'v21,v22',
          key3: 'v31,v32'
         }"

   @Value("#{${populate.map:{}}}")		// 默认值是null
   private Map<String,String> map;

   @Value("#{${populate.map:null}}}")  // 默认值是null
   private Map<String, String> map2;
   
   @Value("#{${populate.map:{k1:'v1',k2:'v2'}}}")  // 默认值是{"k1":"v1","k2":"v2"}
   private Map<String, String> map3;


   
   @Value("#{${populate.mapList:{}}}")		// 值为{"key1":["v11","v12"],"key2":["v21","v22"],"key3":["v31","v32"]}
   private Map<String,List<String>> mapList;