生成器注釋在 Java class 中不起作用

Question

---

此代碼是為學習目的而編寫的。 @Builder 和@Data 注釋已在 Book class 中實現。嘗試在 LibraryApplication.java 中創建相同的構建器時未識別構建器。

如何啟用 Book class 上的注釋

**編輯**：嘗試編譯時會生成以下錯誤。
java.lang.Error：未解決的編譯問題：com.baeldung.LibraryApplication$DataSetup.run(LibraryApplication.java:25) 類型 Book 的方法 builder() 未定義

此外，我正在使用 eclipse 的 STS 實現。我檢查了相同的代碼是否在 eclilpse Oxygen 中有效，但拋出了相同的錯誤

注：項目創建於Spring Boot

書.class

package com.baeldung.domain;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.validation.constraints.NotNull;

import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;


@Data
@NoArgsConstructor
@Builder
@Entity
@AllArgsConstructor
public class Book {

@Id
@GeneratedValue
private Long id;

@NotNull
String name, isbn;

}

LibraryApplication.java

package com.baeldung;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.stereotype.Component;

import com.baeldung.domain.Book;
import com.baeldung.repo.BookingRespository;

@SpringBootApplication
public class LibraryApplication {

@Autowired
private BookingRespository bookingRespository;

@Component
class DataSetup implements ApplicationRunner{

    @Override
    public void run(ApplicationArguments args) throws Exception {
//             bookingRespository.save(Book.builder().name("Way of Kings").isbn("123").build());

    }

}

public static void main(String[] args) {
    SpringApplication.run(LibraryApplication.class, args);
}

}

BookingRepository.java

package com.baeldung.repo;

import org.springframework.data.repository.PagingAndSortingRepository;
import org.springframework.data.rest.core.annotation.RepositoryRestResource;

import com.baeldung.domain.Book;

@RepositoryRestResource(path="books",collectionResourceRel="books")
public interface BookingRespository extends PagingAndSortingRepository<Book, Long>{

}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.1.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.baeldung</groupId>
<artifactId>library</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>library</name>
<description>Demo project for Spring Boot</description>

<properties>
    <java.version>1.8</java.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-actuator</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-rest</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-validation</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>com.h2database</groupId>
        <artifactId>h2</artifactId>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
        <exclusions>
            <exclusion>
                <groupId>org.assertj</groupId>
                <artifactId>assertj-core</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

    <dependency>
        <groupId>com.google.guava</groupId>
        <artifactId>guava</artifactId>
        <version>27.0.1-jre</version>
    </dependency>


</dependencies>

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>

Answer 1

根據@f1sh 的建議 - 如果您使用 mvn 包，這應該可以工作。 但是為了讓它在你的 IDE 中工作（這可能是你遇到這個錯誤的地方），你需要將 lombok 安裝到 eclipse 中：projectlombok.org/setup/eclipse

Answer 2

為了使用來自 Lombok 的任何注釋，必須在我們的 IDE 中安裝 Lombok 插件。 我真誠地希望它對你有用。 你不會遇到任何問題。