使用lombok的@Builder的注解的一个坑
一开发说项目报错
java.lang.Long,java.lang.String,java.lang.String,java.lang.String,java.lang.String,java.lang.Integer,java.lang.Integer,java.util.Date,java.util.Date,java.lang.Integer,java.lang.Integer,java.lang.String,java.lang.String,java.lang.String,java.lang.String,java.lang.Integer
原因: 实际参数列表和形式参数列表长度不同，看报错信息指向
@Builder奇怪了，怎么builder会报错？
正文
看报错信息说是匹配不到全参数的构造函数，因为项目用的是lombok，我的注解如下
已经有默认构造参数了，怎么还会报错？猜想难道builder默认用的是全参数构造函数？尝试加了@AllArgsConstructor，果然好了。上网查了下资料
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The builder annotation creates a so-called 'builder' aspect to the class that is annotated or the class that contains a member which is annotated with @Builder.
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If a member is annotated, it must be either a constructor or a method. If a class is annotated, then a private constructor is generated with all fields as arguments (as if @AllArgsConstructor(AccessLevel.PRIVATE) is present on the class), and it is as if this constructor has been annotated with @Builder instead.
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The effect of @Builder is that an inner class is generated named TBuilder, with a private constructor. Instances of TBuilder are made with the method named builder() which is also generated for you in the class itself (not in the builder class).
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The TBuilder class contains 1 method for each parameter of the annotated constructor / method (each field, when annotating a class), which returns the builder itself. The builder also has a build() method which returns a completed instance of the original type, created by passing all parameters as set via the various other methods in the builder to the constructor or method that was annotated with @Builder. The return type of this method will be the same as the relevant class, unless a method has been annotated, in which case it'll be equal to the return type of that method.
发现它的实现方式是会对标注这个注解的类的所有成员变量，所以在使用@Builder构建的时候如果不显式的对某变量赋值的话默认就是null，因为这个变量此时是在Builder
类里的，通过调用build()方法生成具体T类则是通过私有构造函数来实例化，默认是全参数的构造函数。
@Builder默认的实现方式是在类上添加@AllArgsConstructor(access = AccessLevel.PACKAGE)
