我编写了一个SpringBoot应用程序，它使用了一个rest api并提供了一个rest api。我的模型pojo有camelCase命名属性。应用程序消耗的json具有under_score属性名称。应用程序生成的json具有under_score属性名称。我想使用一个PropertyNamingStrategy，它将在编组/解组时在Java和json名称之间自动进行转换。
我有Java配置尝试设置可以处理此问题的命名策略;
/**
* Configuration for Rest api.
* <p>
* Created by emurphy on 2/25/16.
*/
@Configuration
public class RestConfig
{
/**
* Bean to make jackson automatically convert from
* camelCase (java) to under_scores (json) in property names
*
* @return ObjectMapper that maps from Java camelCase to json under_score names
*/
@Bean
public ObjectMapper jacksonObjectMapper()
{
return new ObjectMapper().setPropertyNamingStrategy(new UpperCaseUnderscoreStrategy());
}
/**
* Property naming strategy that converts both ways between camelCase and under_score
* property names.
*/
public static class UpperCaseUnderscoreStrategy extends PropertyNamingStrategy.PropertyNamingStrategyBase
{
/**
* Converts camelCase to under_score and
* visa versa. The idea is that this
* name strategy can be used for both
* marshalling and unmarshaling.
*
* For example, "userName" would be converted to
* "user_name" and conversely "user_name" would
* be converted to "userName".
*
* @param input formatted as camelCase or under_score string
* @return input converted to opposite format
*/
@Override
public String translate(String input)
{
if (input == null || input.length() == 0)
{
return input; // garbage in, garbage out
}
//
// we always take the first character;
// this preserves initial underscore
//
StringBuilder sb = new StringBuilder();
final int length = input.length();
int i = 0;
//
// skip initial underscores
//
while ((i < length) && ('_' == input.charAt(i)))
{
sb.append(input.charAt(i));
i += 1;
}
while (i < length)
{
//
// find underscores, remove and capitalize next letter
//
while ((i < length) && ('_' != input.charAt(i)) && !Character.isUpperCase(input.charAt(i)))
{
sb.append(input.charAt(i));
i += 1;
}
if(i < length)
{
if('_' == input.charAt(i))
{
// underscore to uppercase
//
// skip underscores
//
while ((i < length) && ('_' == input.charAt(i)))
{
// skip underscores
i += 1;
}
//
// capitalize
//
if (i < length)
{
sb.append(Character.toUpperCase(input.charAt(i)));
i += 1;
}
}
else // uppercase to unscore + lowercase
{
sb.append('_');
sb.append(Character.toLowerCase(input.charAt(i)));
i += 1;
}
}
}
return sb.toString();
}
}
当我的休息服务将Java pojos转换为json以获得响应时，我可以看到命名策略的translate方法被调用。然而，当我通过RestTemplate消耗休息api时，我不会看到这个被调用，并且我生成的pojos没有从传入的json正确初始化;名称需要翻译的所有属性都为null。这迫使我在大多数属性上使用@JsonProperty。我有很多属性和很多pojos - 这是SpringBoot应该帮助的一种非常不优雅的样板解决方案。有没有办法设置一个PropertyNamingStrategy，RestTemplate将用于将传入的json名称从under_score转换为camelCase？
感谢您的帮助。
答案 0 :(得分：6)
创建RestTemplate时，您需要将objectMapper设置为您的@Bean。
此外，您应该将自定义ObjectMapper声明为PropertyNamingStrategy，因此它由Spring构建为单例并为您管理。对public class RestConfig
{
/**
* Bean to make jackson automatically convert from
* camelCase (java) to under_scores (json) in property names
*
* @return ObjectMapper that maps from Java camelCase to json under_score names
*/
@Bean
public ObjectMapper jacksonObjectMapper()
{
return new ObjectMapper().setPropertyNamingStrategy(propertyNamingStrategy());
}
@Bean
public PropertyNamingStrategy propertyNamingStrategy()
{
return new UpperCaseUnderscoreStrategy();
}
@Bean
public RestTemplate restTemplate() {
RestTemplate restTemplate = new RestTemplate();
List<HttpMessageConverter<?>> messageConverters = new ArrayList<>();
MappingJackson2HttpMessageConverter jsonMessageConverter = new MappingJackson2HttpMessageConverter();
jsonMessageConverter.setObjectMapper(jacksonObjectMapper());
messageConverters.add(jsonMessageConverter);
restTemplate.setMessageConverters(messageConverters);
return restTemplate;
}
}
执行相同操作，而不是“新增＆＃39;它并将该类声明为静态。
/**
* Property naming strategy that converts both ways between camelCase and under_score
* property names.
*/
public static class UpperCaseUnderscoreStrategy extends PropertyNamingStrategy.PropertyNamingStrategyBase
{
/**
* Converts camelCase to under_score and
* visa versa. The idea is that this
* name strategy can be used for both
* marshalling and unmarshaling.
*
* For example, "userName" would be converted to
* "user_name" and conversely "user_name" would
* be converted to "userName".
*
* @param input formatted as camelCase or under_score string
* @return input converted to opposite format
*/
@Override
public String translate(String input)
{
if (input == null || input.length() == 0)
{
return input; // garbage in, garbage out
}
//
// we always take the first character;
// this preserves initial underscore
//
StringBuilder sb = new StringBuilder();
final int length = input.length();
int i = 0;
//
// skip initial underscores
//
while ((i < length) && ('_' == input.charAt(i)))
{
sb.append(input.charAt(i));
i += 1;
}
while (i < length)
{
//
// find underscores, remove and capitalize next letter
//
while ((i < length) && ('_' != input.charAt(i)) && !Character.isUpperCase(input.charAt(i)))
{
sb.append(input.charAt(i));
i += 1;
}
if(i < length)
{
if('_' == input.charAt(i))
{
// underscore to uppercase
//
// skip underscores
//
while ((i < length) && ('_' == input.charAt(i)))
{
// skip underscores
i += 1;
}
//
// capitalize
//
if (i < length)
{
sb.append(Character.toUpperCase(input.charAt(i)));
i += 1;
}
}
else // uppercase to unscore + lowercase
{
sb.append('_');
sb.append(Character.toLowerCase(input.charAt(i)));
i += 1;
}
}
}
return sb.toString();
}
}
你的班级是在一个单独的档案中吗？它不需要是静态的。
{{1}}
答案 1 :(得分：2)
只需在您将在您的请求响应中发送或接收的POJO上方添加此注释即可。
@JsonNaming（PropertyNamingStrategy.UpperCamelCaseStrategy.class）
P.S。根据需求，策略可能会有所不同。
答案 2 :(得分：1)
一个简短的答案是使用Spring的objectMapper。好处是它在application.properties中共享相同的配置。因此，您可以在其中设置spring.jackson.property-naming-strategy=SNAKE_CASE或其他任何值，并且它在包括RestTemplate在内的整个应用程序中都是一致的。代码如下。
@Configuration
@RequiredArgsConstructor
public class HTTPConfig {
public final ObjectMapper objectMapper; // provided by spring
@Bean
public RestTemplate restTemplate() {
return new RestTemplateBuilder()
.messageConverters(new MappingJackson2HttpMessageConverter(objectMapper))
.build();
}
}
答案 3 :(得分：0)
我建议你使用这种方法。您也可以将其添加为 spring bean。
private RestTemplate getRestTemplate() {
final RestTemplate restTemplate = new RestTemplate();
final List<HttpMessageConverter<?>> messageConverters = new ArrayList<>();
final MappingJackson2HttpMessageConverter jsonMessageConverter = new MappingJackson2HttpMessageConverter();
jsonMessageConverter.setObjectMapper(new ObjectMapper().setPropertyNamingStrategy(PropertyNamingStrategy.LOWER_CAMEL_CASE));
messageConverters.add(jsonMessageConverter);
restTemplate.setMessageConverters(messageConverters);
return restTemplate;
}