[JAVA] How to use Lombok now

Introduction

When I imported the source for a project, I got a lot of build errors. There are a lot of errors that make XXXBuilder not exist. If you look at build.gradle, you can see that it uses lombok's library, but in fact, you need to install the Lombok plugin in the IDE as well.

Lombok https://projectlombok.org/

Project Lombok is a java library that automatically plugs into your editor and build tools, spicing up your java. Never write another getter or equals method again, with one annotation your class has a fully featured builder, Automate your logging variables, and much more.

Spring Tool Suite

lombok download

https://projectlombok.org/download

Double click on lombok JAR

Click Specify location to select the STS folder

Press the Select button

Click Install / update

Installation is complete.

Idea

File ⇒ Settings ⇒ Plugins ⇒ lombok Enter and search

If it already exists in Installed, you do not need to install it.

Select on the MarketPlace tab and enter lombok to search

Press the Install button

Press the Restart IDE button to complete.

VSCode You can avoid build errors with an extension called Lombok Annotations Support for VS Code. https://marketplace.visualstudio.com/items?itemName=GabrielBB.vscode-lombok

Install "Lombok Annotations Support for VS Code"

Press the Install button

After installing, restart VS Code just in case

How to use Lombok

Lombok features https://projectlombok.org/features/all

Added lombok library to build.gradle

build.gradle

    // https://mvnrepository.com/artifact/org.projectlombok/lombok
    compile group: 'org.projectlombok', name: 'lombok', version: '1.18.12'

@Getter/@Setter

It's easy to understand, but getter and setter methods are automatically generated.

@ToString The toString method is defined and controlled as @ToString (exclude =" age ", callSuper = false)

Only the excluded age field is unused.

@EqualsAndHashCode

Three methods, hashCode, equals and canEqual, are generated.

@NoArgsConstructor, @RequiredArgsConstructor, @AllArgsConstructor

@Value

@Builder

@Data

As shown in the above example, it is a summary of the following annotations.

• @ToString
• @EqualsAndHashCode --@Getter for all non-final fields --@Setter for all non-final fields
• @RequiredArgsConstructor

@Log

@Cleanup Annotation that automatically releases resources. This is convenient because you can omit the resource close process yourself.

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;

import lombok.Cleanup;

public class TestMain {

	public static void main(String[] args) throws Exception {
		@Cleanup
		InputStream in = new FileInputStream(args[0]);
		@Cleanup
		OutputStream out = new FileOutputStream(args[1]);

		byte[] b = new byte[1024];
		while (true) {
			int r = in.read(b);
			if (r == -1) {
				break;
			}
			out.write(b, 0, r);
		}
	}

}

Hakamo val, var, @ NonNull,@ Getter (lazy = true), @Helper, @ Slf4j and so on.

Using these annotations can reduce the amount of bean classes and improve maintenance.

that's all