Question

在发送结果之前，我们希望在JSON响应中添加公共字段（时间戳，版本等）。我们不想在每个控制器中执行此操作。在spring mvc中有没有优雅的方法呢？

另一个类似的问题是，如果参数验证失败，如何返回相同的JSON响应。

Answer 1

是的。你可以使用Spring AOP。您可以拦截您编写的每个服务并从一个地方添加参数。例如，使用Spring Around Advice。注意你需要自己编写返回JsonNode的addParameters函数。祝你好运！

public class DoAroundMethod implements MethodInterceptor {
private static final Logger LOG = LoggerFactory.getLogger(DoAroundMethod.class);
@Autowired
ObjectMapper mapper;

public Object invoke(MethodInvocation methodInvocation) throws Throwable {

    LOG.debug("****SPRING AOP**** DoAroundMethod: Method name : "
            + methodInvocation.getMethod().getName());

    LOG.debug("****SPRING AOP**** DoAroundMethod: Method name : "
            + methodInvocation.getMethod().getName());
    LOG.debug("****SPRING AOP**** DoAroundMethod: Method arguments : "
            + Arrays.toString(methodInvocation.getArguments()));
    // same with MethodBeforeAdvice
    LOG.debug("****SPRING AOP**** DoAroundMethod: Before method executing!");

    try {
        // proceed to original method call
        Object result = methodInvocation.proceed();
        // same with AfterReturningAdvice
        if(result!=null){
            //LOG.debug("Return value "+result.toString());
            try{
                JsonNode jN = mapper.readTree(result.toString());
                result=addParameters(jN);
            }catch(JsonParseException e){
                LOG.debug("****SPRING AOP**** DoAroundMethod: When JsonParse throws Exception!");
                return result;
            }
        }
        LOG.debug("****SPRING AOP**** DoAroundMethod: After method executing!");
        return result;

    } catch (IllegalArgumentException e) {
        // same with ThrowsAdvice
        LOG.debug("****SPRING AOP**** DoAroundMethod: When method throws Exception!");
        throw e;
    }
}

然后将此建议分配给您拥有的所有服务，假设它们都以* Service.java结尾

<bean class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator">
    <property name="beanNames">
        <list>
            <value>*Service</value>
        </list>
    </property>
    <property name="interceptorNames">
        <list>
            <value>regexAdvisor</value>
        </list>
    </property>
</bean>

Answer 2

也许是自定义杰克逊插件或ResponseBodyAdvice？（see this blog post for more details）。

spring mvc在json响应中添加公共字段

2 个答案: