慎用lombok.Builder

本文主要是介绍慎用lombok.Builder，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

lombok是一个Java库，使用注解方式来简化 Java 代码，可以减少诸如getter、setter的方法。
它常用的注解有：

@Getter、@Setter、@ToString 不必多说，分别实现getter、setter、toString、hashCode等方法。
@Data 则是包含上面的那些，有这个可以不需要写上面的注解
@NoArgsConstructor 生成无参构造函数
@AllArgsConstructor 生成有参构造函数
@Builder 、@Accessors 是定义链式调用设置属性值，其中@Accessors需要配置属性(chain = true)才能使用链式调用

在使用lombok.Builder时遇到一个问题，代码如下
请求实体

import lombok.Builder;
import lombok.Data;
import javax.validation.constraints.NotBlank;
import javax.validation.constraints.NotNull;@Data
@Builder
public class SettingRequest {private Long id;@NotNull(message = "请选择店铺")private Integer storeId;... .../*** 配置项，json格式*/@NotBlank(message = "请填写配置项")private String configOptions;
}

controller

@PostMapping("/saveSetting")
public Result<Boolean> saveSetting(@RequestBody @Validated SettingRequest request) {Boolean res = settingService.saveSetting(request);return Result.success(res);
}

前端代码

let obj = {setting: this.form.setting, sales: this.form.other};
this.form.configOptions = JSON.stringify(obj);
saveSetting(this.form).then(res => {if(res.code === 0){this.$modal.msgSuccess("操作成功");}this.getList();
});

请求时后端直接报错

Resolved[org.springframework.http.converter.HttpMessageNotReadableException: 
JSON parse error: Cannot construct instance of `com.xxx.request.SettingRequest` (although at least one Creator exists): cannot deserialize from Object value (no delegate- or property-based Creator); 
nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance of `com.xxx.request.SettingRequest` (although at least one Creator exists): cannot deserialize from Object value (no delegate- or property-based Creator)at [Source: (PushbackInputStream); line: 1, column: 2]]

报错的原因就是无法正常反序列化，最后的解决办法是使用@Accessors(chain = true)替代@Builder即可解决。
具体原因可以分别看一下两个注解生成的代码。

使用@Accessors(chain = true)编译后的代码

public SettingRequest() {
}public Long getId() {return this.id;
}@NotNull(message = "请选择店铺"
)
public Integer getStoreId() {return this.storeId;
}@NotNull(message = "请填写配置项"
)
public String getConfigOptions() {return this.configOptions;
}public SettingRequest setId(Long id) {this.id = id;return this;
}public SettingRequest setStoreId(@NotNull(message = "请选择店铺") Integer storeId) {this.storeId = storeId;return this;
}public SettingRequest setConfigOptions(@NotNull(message = "请填写配置项") String configOptions) {this.configOptions = configOptions;return this;
}//toString()

使用@Builder编译后的代码

SettingRequest(Long id, @NotNull(message = "请选择店铺") Integer storeId, @NotNull(message = "请填写配置项") String configOptions) {this.id = id;this.storeId = storeId;this.configOptions = configOptions;
}public static SettingRequest.SettingRequestBuilder builder() {return new SettingRequest.SettingRequestBuilder();
}@NotNull(message = "请填写配置项"
)
public String getConfigOptions() {return this.configOptions;
}public void setConfigOptions(@NotNull(message = "请填写配置项") String configOptions) {this.configOptions = configOptions;
}public static class SettingRequestBuilder {private Long id;private Integer storeId;private String configOptions;SettingRequestBuilder() {}public SettingRequest.SettingRequestBuilder id(Long id) {this.id = id;return this;}public SettingRequest.SettingRequestBuilder storeId(@NotNull(message = "请选择店铺") Integer storeId) {this.storeId = storeId;return this;}public SettingRequest.SettingRequestBuilder configOptions(@NotNull(message = "请填写配置项") String configOptions) {this.configOptions = configOptions;return this;}public SettingRequest build() {return new SettingRequest(this.id, this.storeId, this.whiteList, this.configOptions);}// toString()}