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Editor to share with you what skills to write concise java code, I believe most people do not know much about it, so share this article for your reference, I hope you can learn a lot after reading this article, let's go to know it!

1. Define profile information

Sometimes we put some variables in the yml configuration file for unified management.

For example

Replace @ Value with @ ConfigurationProperties

Usage

Define the entity of the corresponding field

@ Data// specifies the prefix @ ConfigurationProperties (prefix = "developer") @ Componentpublic class DeveloperProperty {private String name; private String website; private String qq; private String phoneNumber;}

Inject this bean when you use it

@ RestController@RequiredArgsConstructorpublic class PropertyController {final DeveloperProperty developerProperty; @ GetMapping ("/ property") public Object index () {return developerProperty.getName ();} 2. Replace @ Autowired with @ RequiredArgsConstructor

We all know that there are three ways to inject a bean (set injection, constructor injection, annotation injection). Spring recommends that we use a constructor to inject Bean.

Let's take a look at what the previous code looks like after it has been compiled

Provided by RequiredArgsConstructor:lombok

3. Do not return null

Counterexample

Positive example

Avoid unnecessary null pointers when calling methods elsewhere

Optional null judgment

/ / get subdirectory list public List getChild (String pid) {if (V.isEmpty (pid)) {pid = BasicDic.TEMPORARY_DIRECTORY_ROOT;} CatalogueTreeNode node = treeNodeMap.get (pid); return Optional.ofNullable (node) .map (CatalogueTreeNode::getChild) .orElse (Collections.emptyList ());} 4. If else

Not too much if else if, try strategic mode instead

5. Reduce controller business code

The business code is processed on the service layer as far as possible, and it is easy to operate and beautiful to maintain in the later stage.

Counterexample

Positive example

6. Convert an array of strings to a comma-separated string

It usually goes like this:

Public static void main (String [] args) {String strs = ""; String [] arr = new String [] {"aa", "cc", "bb"}; / / string array before conversion StringBuilder sb = new StringBuilder (); for (String ele: arr) {if (sb.length () > 0) {sb.append (",");} sb.append (ele) } strs = sb.toString (); / / comma-delimited string System.out.println (strs);}

A simpler way to write:

Public static void main (String [] args) {String [] arr = new String [] {"aa", "cc", "bb"}; / / pre-converted string array String strs = String.join (",", arr); / / comma-separated string System.out.println (strs) after conversion;} above is all the content of this article entitled "what are the techniques for writing concise java code?" Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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