记lombok@Data和@Builder一起用无法添加无参构造方法的坑

转自：https://blog.csdn.net/w605283073/article/details/89221853

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，会生成无参数构造方法。

// 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。

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

@Data
@Builder
public class Dog {

private String name;

private Integer age;

private String nickName;

private String test;

}
效果

// 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！

@Builder
@Data
@NoArgsConstructor
public class Dog {

private String name;

private Integer age;

private String nickName;

private String test;

}

正确写法如下：

@Builder
@Data
public 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：

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 */ }
}
}