lombok@Data和@Builder一起用无法添加无参构造方法的坑
今天和小伙伴讨论一个mybatis-plus的一个诡异问题，最后定位到原因竟然是lombok@Data和@Builder一起用无法添加无参构造方法引起的,非常隐蔽。
很多框架都是同反射等调用无参数构造方法来创建实例的，需要注意。
单独使用@Data注解，编译后的类文件会生成无参数构造方法（这并不是@Data提供的特性，而是Java自带的特性）。
代码语言：javascript复制 // IntelliJ API Decompiler stub source generated from a class file // Implementation of methods is not available package com.chujianyun.util; public class Dog { private java.lang.String name; private java.lang.Integer age; private java.lang.String nickName; private java.lang.String test; public Dog() { /* compiled code */ } public java.lang.String getName() { /* compiled code */ } public java.lang.Integer getAge() { /* compiled code */ } public java.lang.String getNickName() { /* compiled code */ } public java.lang.String getTest() { /* compiled code */ } public void setName(java.lang.String name) { /* compiled code */ } public void setAge(java.lang.Integer age) { /* compiled code */ } public void setNickName(java.lang.String nickName) { /* compiled code */ } public void setTest(java.lang.String test) { /* compiled code */ } public boolean equals(java.lang.Object o) { /* compiled code */ } protected boolean canEqual(java.lang.Object other) { /* compiled code */ } public int hashCode() { /* compiled code */ } public java.lang.String toString() { /* compiled code */ }}单独使用@Builder注解，发现生成了全属性的构造方法。
代码语言：javascript复制package com.chujianyun.util; public class Dog { private java.lang.String name; private java.lang.Integer age; private java.lang.String nickName; private java.lang.String test; Dog(java.lang.String name, java.lang.Integer age, java.lang.String nickName, java.lang.String test) { /* compiled code */ } public static com.chujianyun.util.Dog.DogBuilder builder() { /* compiled code */ } public static class DogBuilder { private java.lang.String name; private java.lang.Integer age; private java.lang.String nickName; private java.lang.String test; DogBuilder() { /* compiled code */ } public com.chujianyun.util.Dog.DogBuilder name(java.lang.String name) { /* compiled code */ } public com.chujianyun.util.Dog.DogBuilder age(java.lang.Integer age) { /* compiled code */ } public com.chujianyun.util.Dog.DogBuilder nickName(java.lang.String nickName) { /* compiled code */ } public com.chujianyun.util.Dog.DogBuilder test(java.lang.String test) { /* compiled code */ } public com.chujianyun.util.Dog build() { /* compiled code */ } public java.lang.String toString() { /* compiled code */ } }}@Data和@Builder一起用
代码语言：javascript复制@Data@Builderpublic class Dog { private String name; private Integer age; private String nickName; private String test; }效果
代码语言：javascript复制 // IntelliJ API Decompiler stub source generated from a class file // Implementation of methods is not available package com.chujianyun.util; public class Dog { private java.lang.String name; private java.lang.Integer age; private java.lang.String nickName; private java.lang.String test; Dog(java.lang.String name, java.lang.Integer age, java.lang.String nickName, java.lang.String test) { /* compiled code */ } public static com.chujianyun.util.Dog.DogBuilder builder() { /* compiled code */ } public java.lang.String getName() { /* compiled code */ } public java.lang.Integer getAge() { /* compiled code */ } public java.lang.String getNickName() { /* compiled code */ } public java.lang.String getTest() { /* compiled code */ } public void setName(java.lang.String name) { /* compiled code */ } public void setAge(java.lang.Integer age) { /* compiled code */ } public void setNickName(java.lang.String nickName) { /* compiled code */ } public void setTest(java.lang.String test) { /* compiled code */ } public boolean equals(java.lang.Object o) { /* compiled code */ } protected boolean canEqual(java.lang.Object other) { /* compiled code */ } public int hashCode() { /* compiled code */ } public java.lang.String toString() { /* compiled code */ } public static class DogBuilder { private java.lang.String name; private java.lang.Integer age; private java.lang.String nickName; private java.lang.String test; DogBuilder() { /* compiled code */ } public com.chujianyun.util.Dog.DogBuilder name(java.lang.String name) { /* compiled code */ } public com.chujianyun.util.Dog.DogBuilder age(java.lang.Integer age) { /* compiled code */ } public com.chujianyun.util.Dog.DogBuilder nickName(java.lang.String nickName) { /* compiled code */ } public com.chujianyun.util.Dog.DogBuilder test(java.lang.String test) { /* compiled code */ } public com.chujianyun.util.Dog build() { /* compiled code */ } public java.lang.String toString() { /* compiled code */ } }}我们发现外层的Dog类没有了默认的构造方法。
如果手动添加无参数构造方法或者用@NoArgsConstructor注解都会报错！
代码语言：javascript复制@Builder@Data@NoArgsConstructorpublic class Dog { private String name; private Integer age; private String nickName; private String test; }
正确写法如下：
代码语言：javascript复制@Builder@Datapublic class Dog { private String name; private Integer age; private String nickName; private String test; @Tolerate Dog() {}}解释如下
添加函数或者构造方法，让lombok假装它不存在（不感知）。
效果如下：
代码语言：javascript复制package com.chujianyun.util; public class Dog { private java.lang.String name; private java.lang.Integer age; private java.lang.String nickName; private java.lang.String test; Dog() { /* compiled code */ } Dog(java.lang.String name, java.lang.Integer age, java.lang.String nickName, java.lang.String test) { /* compiled code */ } public static com.chujianyun.util.Dog.DogBuilder builder() { /* compiled code */ } public java.lang.String getName() { /* compiled code */ } public java.lang.Integer getAge() { /* compiled code */ } public java.lang.String getNickName() { /* compiled code */ } public java.lang.String getTest() { /* compiled code */ } public void setName(java.lang.String name) { /* compiled code */ } public void setAge(java.lang.Integer age) { /* compiled code */ } public void setNickName(java.lang.String nickName) { /* compiled code */ } public void setTest(java.lang.String test) { /* compiled code */ } public boolean equals(java.lang.Object o) { /* compiled code */ } protected boolean canEqual(java.lang.Object other) { /* compiled code */ } public int hashCode() { /* compiled code */ } public java.lang.String toString() { /* compiled code */ } public static class DogBuilder { private java.lang.String name; private java.lang.Integer age; private java.lang.String nickName; private java.lang.String test; DogBuilder() { /* compiled code */ } public com.chujianyun.util.Dog.DogBuilder name(java.lang.String name) { /* compiled code */ } public com.chujianyun.util.Dog.DogBuilder age(java.lang.Integer age) { /* compiled code */ } public com.chujianyun.util.Dog.DogBuilder nickName(java.lang.String nickName) { /* compiled code */ } public com.chujianyun.util.Dog.DogBuilder test(java.lang.String test) { /* compiled code */ } public com.chujianyun.util.Dog build() { /* compiled code */ } public java.lang.String toString() { /* compiled code */ } }}完美。
