Before I discovered the new writing method in Java, I always initialized List and Map like this:
//初始化List List<string> list = new ArrayList</string><string>(); list.add("www.php.cn"); list.add("string2"); //some other list.add() code...... list.add("stringN"); //初始化Map Map</string><string , String> map = new HashMap</string><string , String>(); map.put("key1", "value1"); map.put("key2", "value2"); //.... some other map.put() code map.put("keyN", "valueN"); </string>
It’s so troublesome. . . . . One day I came across such a method:
//初始化List List<string> list = new ArrayList</string><string>(){{ add("string1"); add("string2"); //some other add() code...... add("stringN"); }}; //初始化Map Map</string><string , String> map = new HashMap</string><string , String>(){{ put("key1", "value1"); put("key2", "php.cn"); //.... some other put() code put("keyN", "valueN"); }}; </string>
Although it seems that I haven’t written much less code, I personally feel that this method is much simpler and smoother haha~
Example, now Yiju editor tested two examples of List to make it simpler
Method one:
Use the mutual conversion method between Array and ArrayList, the code is as follows:
rrayList<String> list = new ArrayList(Arrays.asList("Ryan", "Julie", "Bob"));
Method two:
Use The add method of ArrayList completes the initialization assignment. The code is as follows:
List list = new ArrayList<String>(){{ add("A"); add("B"); }}
For more articles related to some writing methods of List and Map initialization in Java, please pay attention to the PHP Chinese website!