工作中的小知识点

hotool工具类包

引入maven

<dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-http</artifactId>
            <version>${hutool.version}</version>
        </dependency>
        <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-core</artifactId>
            <version>${hutool.version}</version>
        </dependency>

http

获取网络图片的byte数组

String url = "https://img.yzcdn.cn/upload_files/2019/11/04/FkKxYNaJw26i906ze8SUIx4BRjlt.jpg";
//获取图片的byte数组
byte[] bytes = HttpRequest.get(url).timeout(20000).execute().bodyBytes();
//转换为base64字符串
String str= Base64Utils.encodeToString(bytes)；

 Controller

返回byte[],转成图片produces = MediaType.IMAGE_JPEG_VALUE

 @GetMapping(value = "/pic", produces = MediaType.IMAGE_JPEG_VALUE)
 public byte[] getAImg(@Valid @RequestParam(value = "goods_spu_id") Long goodsSpuId, @ApiIgnore UserInfo userInfo) {

get请求写法

注解@RequestParam

value路径参数名

required是否必填

注解@Valid参数效验

注解@NotNull不能为null

注解@ApiIgnore忽略不用传的参数

swagger注解：@ApiParam(value=参数的描述,required=是否必传)

@GetMapping("/getByid")

public String getById(@RequestParam(value = "id",required = true)

@ApiParam(value = "id",required = true)

@Valid @NotNull(message = "id不能为空") Long id, @ApiIgnore UserInfo userInfo) {

 jsckson配置

定义返回实体Data类型统一格式

定义返回的数字类型为String（原因：Long类型超过16位，前端js会丢失精度）

spring:
  jackson:
    date-format: yyyy-MM-dd HH:mm:ss
    time-zone: GMT+8
    generator:
      write_numbers_as_strings: true

在springboot项目中还可以使用如下代码（Long类型转换为String）

@Configuration
public class JacksonConfig {
    /**
     * Jackson全局转化long类型为String，解决jackson序列化时long类型缺失精度问题
     * @return Jackson2ObjectMapperBuilderCustomizer 注入的对象
     */
    @Bean
    public Jackson2ObjectMapperBuilderCustomizer jackson2ObjectMapperBuilderCustomizer() {
        Jackson2ObjectMapperBuilderCustomizer cunstomizer = (builder)->builder.serializerByType(Long.TYPE, ToStringSerializer.instance).serializerByType(Long.class, ToStringSerializer.instance);
        return cunstomizer;
    }
}