零碎的java知识点记录（一）

小知识点

1. Map有getOrDefault("1","0");取不到取默认值
2. 两个不同对象，属性相同进行赋值转换，使用modelMapper

<dependency>
    <groupId>org.modelmapper</groupId>
    <artifactId>modelmapper</artifactId>
    <version>1.1.0</version>
</dependency>

1. controller请求中BindingResult bindingResult通过bindingResult.hasErrors()判断是否报错，下列模板代码可以学习

/**
 * 新增房源接口
 * @param houseForm
 * @param bindingResult
 * @return
 */
@PostMapping("admin/add/house")
@ResponseBody
public ApiResponse addHouse(@Valid @ModelAttribute("form-house-add") HouseForm houseForm, BindingResult bindingResult) {
    if (bindingResult.hasErrors()) {
        return new ApiResponse(HttpStatus.BAD_REQUEST.value(), bindingResult.getAllErrors().get(0).getDefaultMessage(), null);
    }

    if (houseForm.getPhotos() == null || houseForm.getCover() == null) {
        return ApiResponse.ofMessage(HttpStatus.BAD_REQUEST.value(), "必须上传图片");
    }

    Map<SupportAddress.Level, SupportAddressDTO> addressMap = addressService.findCityAndRegion(houseForm.getCityEnName(), houseForm.getRegionEnName());
    if (addressMap.keySet().size() != 2) {
        return ApiResponse.ofStatus(ApiResponse.Status.NOT_VALID_PARAM);
    }

    ServiceResult<HouseDTO> result = houseService.save(houseForm);
    if (result.isSuccess()) {
        return ApiResponse.ofSuccess(result.getResult());
    }

    return ApiResponse.ofSuccess(ApiResponse.Status.NOT_VALID_PARAM);
}

@NotNull(message = "大标题不允许为空!")
@Size(min = 1, max = 30, message = "标题长度必须在1~30之间")
private String title;

@NotNull(message = "必须填写卧室数量")
@Min(value = 1, message = "非法的卧室数量")
private Integer room;

@NotNull(message = "必须选中一个租赁方式")
@Min(value = 0)
@Max(value = 1)
private Integer rentWay;

@Size(max = 255)
private String description;

1. redis管理session配置

@Configuration
@EnableRedisHttpSession(maxInactiveIntervalInSeconds = 86400)
public class RedisSessionConfig {
    @Bean
    public RedisTemplate<String, String> redisTemplate(RedisConnectionFactory factory) {

        return new StringRedisTemplate(factory);
    }
}

<!-- redis session依赖 -->
<dependency>
    <groupId>org.springframework.session</groupId>
    <artifactId>spring-session</artifactId>
</dependency>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>

# session会话存储类型
spring.session.store-type=redis

原文地址：https://www.cnblogs.com/sky-chen/p/9921818.html