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This article mainly introduces the relevant knowledge of "SpringBoot integrates Lombok and how to solve common problems". The editor shows you the operation process through actual cases, and the operation method is simple, fast and practical. I hope this article "SpringBoot integrates Lombok and how to solve common problems" can help you solve the problem.

Lombok

Lombok can simplify java code in the form of simple annotations, thus improving the development efficiency of developers. It is an excellent Java code base, it uses a kind of opportunistic syntax sugar, simplifies the coding of Java, and provides a way to simplify Java code, but Lombok is not a standard Java library.

Java classes that often need to be written during web development take the time to add methods such as getter/setter, constructor, and equals. When there are many attributes, there will be a large number of getter/setter methods, which are very lengthy and do not have much technical content. Once you modify the attributes, it is easy to forget to modify the corresponding methods.

Official website: Project Lombok

1. Common notes on Lombok

Annotations function @ Data annotations on the class; provide getting and setting methods for all properties of the class; provide equals, canEqual, hashCode, toString methods @ Setter annotations on the properties; provide setting methods @ Setter annotations on the properties; provide getting methods @ Log4j annotations on the class; provide a log4j log object @ NoArgsConstructor annotation on the class with the property name log; provide a parameter-free constructor @ AllArgsConstructor annotation on the class Provide the class with an all-parameter constructor @ Cleanup: close the stream @ Builder annotated class to add the constructor pattern @ Synchronized synchronization lock @ SneakyThrows to catch the exception, similar to the try/catch catch exception @ NonNull to add this note to the parameter. When the parameter is null, it throws a null pointer exception @ Value annotation and is similar to @ Data. All member variables are defined as private final modifier by default, and no set method is generated.

2. Reasons for the failure of Lombok annotations

After pom.xml introduces the Lombok dependency, you also need to install the Lombok plug-in to restart IDEA to take effect.

Integration process 1. Introduce Lombok dependencies:

Copy the following code and insert it into the pom.xml, wait for the maven repository to download and install the dependency automatically, and click manually to import the package without setting the automatic guide.

Org.projectlombok lombok 1.18.12 provided

two。 Install the Lombok plug-in

Click File- "Setting-" Plugins- in IDEA to search for Lombok to install the plug-in, and restart IDEA

3. Using Lombok to generate getter/setter and other method program code examples for attributes

a. Entity classes are not written in Lombok (the program is fat and unattractive)

These methods can be generated automatically by using the keyboard shortcuts that come with IDE:

Package com.dvms.entity;/* * filename: Anglerecord * creator: CJW * creation time: 14:40 on 2020-6-6 * description: record * / public class Record {private String time; private String device; private String state; public Record (String time, String device, String state) {this.time = time; this.device = device; this.state = state } public Record () {} public String getTime () {return this.time;} public String getDevice () {return this.device;} public String getState () {return this.state;} public Record setTime (String time) {this.time = time; return this;} public Record setDevice (String device) {this.device = device Return this;} public Record setState (String state) {this.state = state; return this;} public boolean equals (final Object o) {if (o = = this) return true; if (! (o instanceof Record)) return false; final Record other = (Record) o; if (! other.canEqual ((Object) this) return false; final Object this$time = this.getTime () Final Object other$time = other.getTime (); if (this$time = = null? Other$time! = null:! this$time.equals (other$time) return false; final Object this$device = this.getDevice (); final Object other$device = other.getDevice (); if (this$device = = null? Other$device! = null:! this$device.equals (other$device) return false; final Object this$state = this.getState (); final Object other$state = other.getState (); if (this$state = = null? Other$state! = null:! this$state.equals (other$state) return false; return true;} protected boolean canEqual (final Object other) {return other instanceof Record;} public int hashCode () {final int PRIME = 59; int result = 1; final Object $time = this.getTime (); result = result * PRIME + ($time = = null? 43: $time.hashCode (); final Object $device = this.getDevice () Result = result * PRIME + ($device= = null? 43: $device.hashCode ()); final Object $state= this.getState (); result = result * PRIME + ($state= = null? 43: $state.hashCode (); return result;} public String toString () {return "Record (time=" + this.getTime () + ", device=" + this.getDevice () + ", state=" + this.getState () + ")";}}

b. Introduce Lombok generation method (the program is slim and looks very comfortable)

You can add notes manually according to your needs, or you can right-click-"Refactor-" Lomok-

Package com.dvms.entity;/* * filename: Anglerecord * creator: CJW * creation time: 14:40 on 2020-6-6 * description: record * / import lombok.AllArgsConstructor;import lombok.Data;import lombok.NoArgsConstructor;import lombok.ToString;import lombok.experimental.Accessors;@Data@ToString@AllArgsConstructor@NoArgsConstructor@Accessors (chain = true) / / chain call public class Record {private String time; private String device; private String state } pros and cons (possible problems are solutions)

Advantages:

Lombok can automatically generate getter/setter, equals and toString for attributes at compile time through annotations, saving the trouble of manually rebuilding these codes and making the program entity class (entity/pojo) code look slimmer and more compelling.

Shortcomings (problems that may arise):

If it is a personal development, the following problems may occur:

1.Lombok currently supports JDK1.8, which may fail after upgrading the JDK version. Solution:

a. Generate getter/setter,equals,hashCode,toString and constructor through the shortcut key Alt+Insert of IDE

b. Use the DeLombok tool to generate these methods, and DeLombok is included in the latest version. Right-click Refactored- > DeLombok:

Or use a command:

Java-jar lombok.jar delombok src-d src-delomboked

Convert the class files implemented by Lombok annotations to Java source files that do not use Lombok.

2.Lombok hides the details of the JavaBean package, and the program looks simple but not readable. In addition, try not to use this annotation @ AllArgsConstructor, which provides a giant constructor that gives outsiders the opportunity to modify all properties in the class when initializing the object. After all, some properties of the object in the Java class should not be modified. At the same time, if there are many attributes in a Java class, Lombok injects a constructor with many parameters into the Java class, and the order of the constructor parameters is completely controlled by Lombok.

3. After writing Javabean code with Lombok, the rest of the code that depends on this javabean needs to introduce Lombok dependencies, resulting in increased code coupling. At the same time, you also need to install the plug-in for Lombok in IDE.

4. If it is collaborative development, you need to pay attention to the following issues:

When we introduce the Lombok plug-in into our program code, others must also download and introduce the Lombok plug-in, otherwise the Java code may not work properly.

This is the end of the introduction to "SpringBoot integrates Lombok and how to solve common problems". Thank you for your reading. If you want to know more about the industry, you can follow the industry information channel. The editor will update different knowledge points for you every day.

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