可以看第三部分的例子， @Builder 注解产生的 Builder 类的构造方法默认并不能限定必传参数。

如果非要使用 @Builder ，那么不要用 @Data ，要用 @Getter。相对来说，反而 @Accessors 的行为更符合这个要求。

实际使用中经常发现 @Builder 滥用的情况，有些仅仅一两个属性的类也都要用 @Builder，真的没必要用，直接用全参的构造方法都比这更简洁。

package io.gitrebase.demo;
import lombok.AllArgsConstructor;import lombok.Builder;import lombok.Data;import lombok.NoArgsConstructor;
@Data@NoArgsConstructor@AllArgsConstructorpublic class APIResponse<T> {
    private T payload;
    private Status status;
}

使用示例：

package io.gitrebase.demo;
import lombok.extern.slf4j.Slf4j;import org.springframework.http.HttpStatus;import org.springframework.web.bind.annotation.ResponseStatus;import org.springframework.web.bind.annotation.RestControllerAdvice;
@Slf4j@RestControllerAdvice(assignableTypes = io.gitrebase.demo.RestApplication.class)public class ApplicationExceptionHandler {
    @ResponseStatus(code = HttpStatus.INTERNAL_SERVER_ERROR)    public APIResponse handleException(Exception exception) {        log.error("Unhandled Exception", exception);        Status status = new Status();        status.setResponseCode("RESPONSE_CODE_IDENTIFIER");        status.setDescription("Bla Bla Bla");        APIResponse response = new APIResponse();        response.setStatus(status);        return response;    }
}

package io.gitrebase.demo;
import lombok.AllArgsConstructor;import lombok.Builder;import lombok.Data;import lombok.NoArgsConstructor;
@Builder@Data@NoArgsConstructor@AllArgsConstructorpublic class APIResponse<T> {
    private T payload;
    private Status status;
}

等价代码：

package io.gitrebase.demo;
import lombok.AccessLevel;import lombok.AllArgsConstructor;import lombok.Getter;
@Getter// Make constructor private so object cannot be created outside the class// Allowing only PersonBuilder.build to create an instance of the class@AllArgsConstructor(access = AccessLevel.PRIVATE)public class Person {
    private String firstName;    private String lastName;    private String email;    private String mobile;
    // PersonBuilder can only be created with  firstName, lastName    // which implies that Person object ll always be instantiated with firstName & lastName    public static PersonBuilder builder(String firstName, String lastName) {        return new PersonBuilder(firstName, lastName);    }
    public static class PersonBuilder {
        private final String firstName;        private final String lastName;        private String email;        private String mobile;
        // Make constructor private so object cannot be created outside the class        // Allowing only Person.builder to create an instance of  PersonBuilder        private PersonBuilder(String firstName, String lastName) {            this.firstName = firstName;            this.lastName = lastName;        }
        public PersonBuilder email(String email) {            this.email = email;            return this;        }
        public PersonBuilder mobile(String mobile) {            this.mobile = mobile;            return this;        }
        public Person build() {            return new Person(firstName, lastName, email, mobile);        }
    }
}

使用示例：

package io.gitrebase.demo;
import lombok.extern.slf4j.Slf4j;import org.springframework.http.HttpStatus;import org.springframework.web.bind.annotation.ResponseStatus;import org.springframework.web.bind.annotation.RestControllerAdvice;
@Slf4j@RestControllerAdvice(basePackageClasses = io.gitrebase.demo.RestApplication.class)public class ApplicationExceptionHandler {
    @ResponseStatus(code = HttpStatus.INTERNAL_SERVER_ERROR)    public APIResponse handleException(Exception exception) {        log.error("Unhandled Exception", exception);        return APIResponse.builder().status(Status.builder()                .responseCode("RESPONSE_CODE_IDENTIFIER")                .description("Bla Bla Bla")                .build())                .build();    }
}

package io.gitrebase.demo;
import lombok.Data;import lombok.experimental.Accessors;

@Data@Accessors(chain = true)public class APIResponse<T> {
    private T payload;
    private Status status;
}

等价代码：

package io.gitrebase.demo;
import lombok.experimental.Accessors;
@Accessors(chain = true)public class APIResponse<T> {
    private T payload;
    private Status status;
    public T getPayload() {        return this.payload;    }
    public APIResponse<T> setPayload(T payload) {        this.payload = payload;        return this;    }
    public Status getStatus() {        return this.status;    }
    public APIResponse<T> setStatus(Status status) {        this.status = status;        return this;    }}

使用示例：

package io.gitrebase.demo;
import lombok.extern.slf4j.Slf4j;import lombok.var;import org.springframework.http.HttpStatus;import org.springframework.web.bind.annotation.ResponseStatus;import org.springframework.web.bind.annotation.RestControllerAdvice;
@Slf4j@RestControllerAdvice(basePackageClasses = io.gitrebase.demo.RestApplication.class)public class ApplicationExceptionHandler {
    @ResponseStatus(code = HttpStatus.INTERNAL_SERVER_ERROR)    public APIResponse handleException(Exception exception) {        log.error("Unhandled Exception", exception);        var status = new Status().setResponseCode("RESPONSE_CODE_IDENTIFIER").setDescription("Bla Bla Bla");        return new APIResponse().setStatus(status);    }
}

原文中给的示例相对简单，实际运用时，如果属性较多，且分为必传属性和选填属性时，可以将必传参数定义在构造方法中，加上 @Accessors 注解，这样就可以实现必传参数的传入，又可以实现选填参数的链式调用。

import lombok.Accessors;
// 使用 @Accessors 注解，设置 chain = true，生成返回 this 的 setter 方法@Accessors(chain = true)public class Student {    // 定义必传属性，使用 final 修饰，不提供 setter 方法    private final int studentId; // 学生ID    private final int grade; // 年级    private final int classNum; // 班级
    // 定义选填属性，提供 setter 方法    private String name; // 姓名    private String gender; // 性别    private String address; // 住址
    // 定义构造方法，接收必传参数    public Student(int studentId, int grade, int classNum) {        this.studentId = studentId;        this.grade = grade;        this.classNum = classNum;    }
    // 省略 getter 和 setter 方法}
// 使用示例Student student = new Student(1001, 3, 8) // 创建一个学生对象，传入必传参数        .setName("张三") // 设置姓名        .setGender("男") // 设置性别        .setAddress("北京市朝阳区"); // 设置住址

另外该注解还有很多设置项，感兴趣可以进一步研究：

/** * A container for settings for the generation of getters, setters and "with"-ers. * <p> * Complete documentation is found at <a href="https://projectlombok.org/features/experimental/Accessors">the project lombok features page for &#64;Accessors</a>. * <p> * Using this annotation does nothing by itself; an annotation that makes lombok generate getters, setters, or "with"-ers * such as {@link lombok.Setter} or {@link lombok.Data} is also required. */@Target({ElementType.TYPE, ElementType.FIELD})@Retention(RetentionPolicy.SOURCE)public @interface Accessors {    /**     * If true, accessors will be named after the field and not include a {@code get} or {@code set}     * prefix. If true and {@code chain} is omitted, {@code chain} defaults to {@code true}.<br>     * NB: This setting has no effect on {@code @With}; they always get a "with" prefix.<br>     * <strong>default: false</strong>     *      * @return Whether or not to make fluent methods (named {@code fieldName()}, not for example {@code setFieldName}).     */    boolean fluent() default false;        /**     * If true, setters return {@code this} instead of {@code void}.     * <strong>default: false</strong>, unless {@code fluent=true}, then <strong>default: true</strong>     *      * @return Whether or not setters should return themselves (chaining) or {@code void} (no chaining).     */    boolean chain() default false;        /**     * If true, generated accessors will be marked  {@code final}.     * <strong>default: false</strong>     *      * @return Whether or not accessors should be marked {@code final}.     */    boolean makeFinal() default false;        /**     * If present, only fields with any of the stated prefixes are given the getter/setter treatment.     * Note that a prefix only counts if the next character is NOT a lowercase character or the last     * letter of the prefix is not a letter (for instance an underscore). If multiple fields     * all turn into the same name when the prefix is stripped, an error will be generated.     *      * @return If you are in the habit of prefixing your fields (for example, you name them {@code fFieldName}, specify such prefixes here).     */    String[] prefix() default {};}

参考链接：

[1]https://medium.com/gitrebase/oh-stop-using-builder-9061a5911d8c

[2]https://www.baeldung.com/lombok-builder-inheritance