Spring Boot 统一设置Json数据返回风格（Java驼峰命名转下划线）

绝地灬酷狼 2022-04-05 13:23 1321阅读 0赞

# 编写重写了WebMvcConfigurerAdapter的配置类 #

@Configuration
    @EnableWebMvc
    public class WebMvcConfig extends WebMvcConfigurerAdapter { 
    
    	/** * 统一输出风格 * See {@link com.fasterxml.jackson.databind.PropertyNamingStrategy.SnakeCaseStrategy} for details. * @param converters */
    	@Override
    	public void extendMessageConverters(List<HttpMessageConverter<?>> converters) { 
    		for (int i = 0; i < converters.size(); i++) { 
    			if (converters.get(i) instanceof MappingJackson2HttpMessageConverter) { 
    				ObjectMapper objectMapper = new ObjectMapper();
    				// 统一返回数据的输出风格
    				objectMapper.setPropertyNamingStrategy(new PropertyNamingStrategy.SnakeCaseStrategy());
    				objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
    				objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
    				objectMapper.setTimeZone(TimeZone.getTimeZone("GMT+8"));
    				MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();
    				converter.setObjectMapper(objectMapper);
    				converters.set(i, converter);
    				break;
    			}
    		}// end for
    	}
    }

# 编写Controller #

@GetMapping("/api/getUser")
    	public Object getUser() { 
    		List<User> users = new ArrayList<User>();
    		users.add(new User("1", "小京", "北京"));
    		users.add(new User("2", "小海", "上海"));
    		users.add(new User("1", "小广", null));
    		return users;
    	}
    
    	@Data
    	@AllArgsConstructor
    	class User { 
    		private String id;
    
    		private String userName;
    
    		private String addr;
    	}

# 查看返回结果 #

调用`/api/getUser`：

[
        { 
            "id": "1",
            "user_name": "小京",
            "addr": "北京"
        },
        { 
            "id": "2",
            "user_name": "小海",
            "addr": "上海"
        },
        { 
            "id": "1",
            "user_name": "小广"
        }
    ]

# 风格阐述 #

*  Java属性名称统一为如下规则

"userName" is translated to "user_name"
    "UserName" is translated to "user_name"
    "USER_NAME" is translated to "user_name"
    "user_name" is translated to "user_name" (unchanged)
    "user" is translated to "user" (unchanged)
    "User" is translated to "user"
    "USER" is translated to "user"
    "_user" is translated to "user"
    "_User" is translated to "user"
    "__user" is translated to "_user" (the first of two underscores was removed)
    "user__name" is translated to "user__name" (unchanged, with two underscores)

*  空字段不进行返回。如：测试数据中的`小广`，没有地址信息，则不返回’addr’字段