绑定Spring MVC命令对象时如何自定义参数名称?


76

我有一个命令对象:

public class Job {
    private String jobType;
    private String location;
}

这受spring-mvc约束:

@RequestMapping("/foo")
public Strnig doSomethingWithJob(Job job) {
   ...
}

哪个适用于http://example.com/foo?jobType=permanent&location=Stockholm。但是现在我需要使它适用于以下URL:

http://example.com/foo?jt=permanent&loc=Stockholm

显然,我不想更改命令对象,因为字段名称必须保持较长(因为它们在代码中使用了)。我该如何自定义呢?是否可以选择执行以下操作:

public class Job {
    @RequestParam("jt")
    private String jobType;
    @RequestParam("loc")
    private String location;
}

这是行不通的(@RequestParam无法应用于字段)。

我正在考虑的事情是类似于FormHttpMessageConverter目标对象并读取目标对象上的自定义注释的自定义消息转换器


2
Spring 4中已经没有一些“本机”解决方案了吗?
MartinŽdila'15

请与我类似的问题在这里帮助stackoverflow.com/questions/38171022/...
SourceVisor

Answers:


33

该解决方案更加简洁,但是需要使用RequestMappingHandlerAdapter,该<mvc:annotation-driven />功能在启用时由Spring使用。希望它能帮助到别人。想法是像这样扩展ServletRequestDataBinder:

 /**
 * ServletRequestDataBinder which supports fields renaming using {@link ParamName}
 *
 * @author jkee
 */
public class ParamNameDataBinder extends ExtendedServletRequestDataBinder {

    private final Map<String, String> renameMapping;

    public ParamNameDataBinder(Object target, String objectName, Map<String, String> renameMapping) {
        super(target, objectName);
        this.renameMapping = renameMapping;
    }

    @Override
    protected void addBindValues(MutablePropertyValues mpvs, ServletRequest request) {
        super.addBindValues(mpvs, request);
        for (Map.Entry<String, String> entry : renameMapping.entrySet()) {
            String from = entry.getKey();
            String to = entry.getValue();
            if (mpvs.contains(from)) {
                mpvs.add(to, mpvs.getPropertyValue(from).getValue());
            }
        }
    }
}

合适的处理器:

/**
 * Method processor supports {@link ParamName} parameters renaming
 *
 * @author jkee
 */

public class RenamingProcessor extends ServletModelAttributeMethodProcessor {

    @Autowired
    private RequestMappingHandlerAdapter requestMappingHandlerAdapter;

    //Rename cache
    private final Map<Class<?>, Map<String, String>> replaceMap = new ConcurrentHashMap<Class<?>, Map<String, String>>();

    public RenamingProcessor(boolean annotationNotRequired) {
        super(annotationNotRequired);
    }

    @Override
    protected void bindRequestParameters(WebDataBinder binder, NativeWebRequest nativeWebRequest) {
        Object target = binder.getTarget();
        Class<?> targetClass = target.getClass();
        if (!replaceMap.containsKey(targetClass)) {
            Map<String, String> mapping = analyzeClass(targetClass);
            replaceMap.put(targetClass, mapping);
        }
        Map<String, String> mapping = replaceMap.get(targetClass);
        ParamNameDataBinder paramNameDataBinder = new ParamNameDataBinder(target, binder.getObjectName(), mapping);
        requestMappingHandlerAdapter.getWebBindingInitializer().initBinder(paramNameDataBinder, nativeWebRequest);
        super.bindRequestParameters(paramNameDataBinder, nativeWebRequest);
    }

    private static Map<String, String> analyzeClass(Class<?> targetClass) {
        Field[] fields = targetClass.getDeclaredFields();
        Map<String, String> renameMap = new HashMap<String, String>();
        for (Field field : fields) {
            ParamName paramNameAnnotation = field.getAnnotation(ParamName.class);
            if (paramNameAnnotation != null && !paramNameAnnotation.value().isEmpty()) {
                renameMap.put(paramNameAnnotation.value(), field.getName());
            }
        }
        if (renameMap.isEmpty()) return Collections.emptyMap();
        return renameMap;
    }
}

注解:

/**
 * Overrides parameter name
 * @author jkee
 */

@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface ParamName {

    /**
     * The name of the request parameter to bind to.
     */
    String value();

}

春季配置:

<mvc:annotation-driven>
    <mvc:argument-resolvers>
        <bean class="ru.yandex.metrika.util.params.RenamingProcessor">
            <constructor-arg name="annotationNotRequired" value="true"/>
        </bean>
    </mvc:argument-resolvers>
</mvc:annotation-driven> 

最后,用法(如Bozho解决方案):

public class Job {
    @ParamName("job-type")
    private String jobType;
    @ParamName("loc")
    private String location;
}

非常感谢您的解决方案!注意事项:这保留了DateTimeFormat注释的功能,即@ParamName注释Date字段可以另外使用注释@DateTimeFormat(pattern = "yyyy-MM-dd")
西蒙(Simon)

6
对于所有Java配置风扇,Java中的Spring上下文配置如下所示: @Configuration public class WebContextConfiguration extends WebMvcConfigurationSupport { @Override protected void addArgumentResolvers( List<HandlerMethodArgumentResolver> argumentResolvers) { argumentResolvers.add(renamingProcessor()); } @Bean protected RenamingProcessor renamingProcessor() { return new RenamingProcessor(true); } } 注意,extends WebMvcConfigurationSupport替换为@EnableWebMvc<mvc:annotation-driven />
西蒙(Simon)

请与我类似的问题在这里帮助stackoverflow.com/questions/38171022/...
SourceVisor

2
从Spring 4.2开始,有什么可以帮助简化此过程的吗?
chrismarx '16

2
我已经通过替换addArgumentResolvers为bean后处理器来解决:pastebin.com/07ws0uUZ
dtrunk

15

这是我的工作:

首先,一个参数解析器:

/**
 * This resolver handles command objects annotated with @SupportsAnnotationParameterResolution
 * that are passed as parameters to controller methods.
 * 
 * It parses @CommandPerameter annotations on command objects to
 * populate the Binder with the appropriate values (that is, the filed names
 * corresponding to the GET parameters)
 * 
 * In order to achieve this, small pieces of code are copied from spring-mvc
 * classes (indicated in-place). The alternative to the copied lines would be to
 * have a decorator around the Binder, but that would be more tedious, and still
 * some methods would need to be copied.
 * 
 * @author bozho
 * 
 */
public class AnnotationServletModelAttributeResolver extends ServletModelAttributeMethodProcessor {

    /**
     * A map caching annotation definitions of command objects (@CommandParameter-to-fieldname mappings)
     */
    private ConcurrentMap<Class<?>, Map<String, String>> definitionsCache = Maps.newConcurrentMap();

    public AnnotationServletModelAttributeResolver(boolean annotationNotRequired) {
        super(annotationNotRequired);
    }

    @Override
    public boolean supportsParameter(MethodParameter parameter) {
        if (parameter.getParameterType().isAnnotationPresent(SupportsAnnotationParameterResolution.class)) {
            return true;
        }
        return false;
    }

    @Override
    protected void bindRequestParameters(WebDataBinder binder, NativeWebRequest request) {
        ServletRequest servletRequest = request.getNativeRequest(ServletRequest.class);
        ServletRequestDataBinder servletBinder = (ServletRequestDataBinder) binder;
        bind(servletRequest, servletBinder);
    }

    @SuppressWarnings("unchecked")
    public void bind(ServletRequest request, ServletRequestDataBinder binder) {
        Map<String, ?> propertyValues = parsePropertyValues(request, binder);
        MutablePropertyValues mpvs = new MutablePropertyValues(propertyValues);
        MultipartRequest multipartRequest = WebUtils.getNativeRequest(request, MultipartRequest.class);
        if (multipartRequest != null) {
            bindMultipart(multipartRequest.getMultiFileMap(), mpvs);
        }

        // two lines copied from ExtendedServletRequestDataBinder
        String attr = HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE;
        mpvs.addPropertyValues((Map<String, String>) request.getAttribute(attr));
        binder.bind(mpvs);
    }

    private Map<String, ?> parsePropertyValues(ServletRequest request, ServletRequestDataBinder binder) {

        // similar to WebUtils.getParametersStartingWith(..) (prefixes not supported)
        Map<String, Object> params = Maps.newTreeMap();
        Assert.notNull(request, "Request must not be null");
        Enumeration<?> paramNames = request.getParameterNames();
        Map<String, String> parameterMappings = getParameterMappings(binder);
        while (paramNames != null && paramNames.hasMoreElements()) {
            String paramName = (String) paramNames.nextElement();
            String[] values = request.getParameterValues(paramName);

            String fieldName = parameterMappings.get(paramName);
            // no annotation exists, use the default - the param name=field name
            if (fieldName == null) {
                fieldName = paramName;
            }

            if (values == null || values.length == 0) {
                // Do nothing, no values found at all.
            } else if (values.length > 1) {
                params.put(fieldName, values);
            } else {
                params.put(fieldName, values[0]);
            }
        }

        return params;
    }

    /**
     * Gets a mapping between request parameter names and field names.
     * If no annotation is specified, no entry is added
     * @return
     */
    private Map<String, String> getParameterMappings(ServletRequestDataBinder binder) {
        Class<?> targetClass = binder.getTarget().getClass();
        Map<String, String> map = definitionsCache.get(targetClass);
        if (map == null) {
            Field[] fields = targetClass.getDeclaredFields();
            map = Maps.newHashMapWithExpectedSize(fields.length);
            for (Field field : fields) {
                CommandParameter annotation = field.getAnnotation(CommandParameter.class);
                if (annotation != null && !annotation.value().isEmpty()) {
                    map.put(annotation.value(), field.getName());
                }
            }
            definitionsCache.putIfAbsent(targetClass, map);
            return map;
        } else {
            return map;
        }
    }

    /**
     * Copied from WebDataBinder.
     * 
     * @param multipartFiles
     * @param mpvs
     */
    protected void bindMultipart(Map<String, List<MultipartFile>> multipartFiles, MutablePropertyValues mpvs) {
        for (Map.Entry<String, List<MultipartFile>> entry : multipartFiles.entrySet()) {
            String key = entry.getKey();
            List<MultipartFile> values = entry.getValue();
            if (values.size() == 1) {
                MultipartFile value = values.get(0);
                if (!value.isEmpty()) {
                    mpvs.add(key, value);
                }
            } else {
                mpvs.add(key, values);
            }
        }
    }
}

然后使用后处理器注册参数解析器。它应该注册为<bean>

/**
 * Post-processor to be used if any modifications to the handler adapter need to be made
 * 
 * @author bozho
 *
 */
public class AnnotationHandlerMappingPostProcessor implements BeanPostProcessor {

    @Override
    public Object postProcessAfterInitialization(Object bean, String arg1)
            throws BeansException {
        return bean;
    }

    @Override
    public Object postProcessBeforeInitialization(Object bean, String arg1)
            throws BeansException {
        if (bean instanceof RequestMappingHandlerAdapter) {
            RequestMappingHandlerAdapter adapter = (RequestMappingHandlerAdapter) bean;
            List<HandlerMethodArgumentResolver> resolvers = adapter.getCustomArgumentResolvers();
            if (resolvers == null) {
                resolvers = Lists.newArrayList();
            }
            resolvers.add(new AnnotationServletModelAttributeResolver(false));
            adapter.setCustomArgumentResolvers(resolvers);
        }

        return bean;
    }

}

拥有一个完整的示例将非常有帮助,因为我无法构建上述示例。
Ismar Slomic

请与我类似的问题在这里帮助stackoverflow.com/questions/38171022/...
SourceVisor

这个不完整的代码如何成为公认的答案?它缺少一些类,如SupportsAnnotationParameterResolution@CommandPattern@SupportsCustomizedBinding,以及在进口Maps.*Lists.*
membersound

好的,SupportsAnnotationParameterResolution为SupportsCustomizedBinding。因此,在创建两个注释时,该方法都行得通!
membersound

9

在Spring 3.1中,ServletRequestDataBinder为附加绑定值提供了一个钩子:

protected void addBindValues(MutablePropertyValues mpvs, ServletRequest request) {
}

ExtendedServletRequestDataBinder子类使用它来添加URI模板变量作为绑定值。您可以进一步扩展它,以便添加特定于命令的字段别名。

您可以重写RequestMappingHandlerAdapter.createDataBinderFactory(..)以提供自定义WebDataBinder实例。从控制器的角度来看,它可能看起来像这样:

@InitBinder
public void initBinder(MyWebDataBinder binder) {
   binder.addFieldAlias("jobType", "jt");
   // ...
}

谢谢,但是如果我需要重写.createDtaBinderFactory,这意味着我应该替换RequestMappingHandlerAdapter,这意味着我不能使用<mvc:annotation-driven />,对吧?
博若

别客气。是的,使用<mvc:annotation-driven />不能插入自定义RequestMappingHandlerMapping。但是,您可以使用MVC Java配置很容易地做到这一点。
罗森·斯托扬切夫

@RossenStoyanchev:你能解释我如何能插上定制MyWebDataBinder@EnableWebMvc?我看到我必须继承ExtendedServletRequestDataBinder并通过继承返回它ServletRequestDataBinderFactory。现在,我可以通过子类化RequestMappingHandlerAdapter和重写来返回这家新工厂createDataBinderFactory()。但是如何强制Spring MVC使用我的子类RequestMappingHandlerAdapter?它创建于WebMvcConfigurationSupport...
Tomasz Nurkiewicz 2012年

1
@TomaszNurkiewicz,也许您已经弄清楚了,但是如果没有看的话,请参阅参考文档..static.springsource.org
spring/

@RossenStoyanchev:其实不是很紧急,但是感谢您的建议,它终于可以工作了,+ 1!
Tomasz Nurkiewicz 2012年

5

感谢@jkee的回答。
这是我的解决方案。
首先,一个自定义注释:

@Inherited
@Documented
@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface ParamName {

  /**
   * The name of the request parameter to bind to.
   */
  String value();

}

客户DataBinder:

public class ParamNameDataBinder extends ExtendedServletRequestDataBinder {

  private final Map<String, String> paramMappings;

  public ParamNameDataBinder(Object target, String objectName, Map<String, String> paramMappings) {
    super(target, objectName);
    this.paramMappings = paramMappings;
  }

  @Override
  protected void addBindValues(MutablePropertyValues mutablePropertyValues, ServletRequest request) {
    super.addBindValues(mutablePropertyValues, request);
    for (Map.Entry<String, String> entry : paramMappings.entrySet()) {
      String paramName = entry.getKey();
      String fieldName = entry.getValue();
      if (mutablePropertyValues.contains(paramName)) {
        mutablePropertyValues.add(fieldName, mutablePropertyValues.getPropertyValue(paramName).getValue());
      }
    }
  }

}

参数解析器:

public class ParamNameProcessor extends ServletModelAttributeMethodProcessor {

  @Autowired
  private RequestMappingHandlerAdapter requestMappingHandlerAdapter;

  private static final Map<Class<?>, Map<String, String>> PARAM_MAPPINGS_CACHE = new ConcurrentHashMap<>(256);

  public ParamNameProcessor() {
    super(false);
  }

  @Override
  public boolean supportsParameter(MethodParameter parameter) {
    return parameter.hasParameterAnnotation(RequestParam.class)
        && !BeanUtils.isSimpleProperty(parameter.getParameterType())
        && Arrays.stream(parameter.getParameterType().getDeclaredFields())
        .anyMatch(field -> field.getAnnotation(ParamName.class) != null);
  }

  @Override
  protected void bindRequestParameters(WebDataBinder binder, NativeWebRequest nativeWebRequest) {
    Object target = binder.getTarget();
    Map<String, String> paramMappings = this.getParamMappings(target.getClass());
    ParamNameDataBinder paramNameDataBinder = new ParamNameDataBinder(target, binder.getObjectName(), paramMappings);
    requestMappingHandlerAdapter.getWebBindingInitializer().initBinder(paramNameDataBinder, nativeWebRequest);
    super.bindRequestParameters(paramNameDataBinder, nativeWebRequest);
  }

  /**
   * Get param mappings.
   * Cache param mappings in memory.
   *
   * @param targetClass
   * @return {@link Map<String, String>}
   */
  private Map<String, String> getParamMappings(Class<?> targetClass) {
    if (PARAM_MAPPINGS_CACHE.containsKey(targetClass)) {
      return PARAM_MAPPINGS_CACHE.get(targetClass);
    }
    Field[] fields = targetClass.getDeclaredFields();
    Map<String, String> paramMappings = new HashMap<>(32);
    for (Field field : fields) {
      ParamName paramName = field.getAnnotation(ParamName.class);
      if (paramName != null && !paramName.value().isEmpty()) {
        paramMappings.put(paramName.value(), field.getName());
      }
    }
    PARAM_MAPPINGS_CACHE.put(targetClass, paramMappings);
    return paramMappings;
  }

}

最后,一个用于将ParamNameProcessor添加到第一个参数解析器的bean配置:

@Configuration
public class WebConfig {

  /**
   * Processor for annotation {@link ParamName}.
   *
   * @return ParamNameProcessor
   */
  @Bean
  protected ParamNameProcessor paramNameProcessor() {
    return new ParamNameProcessor();
  }

  /**
   * Custom {@link BeanPostProcessor} for adding {@link ParamNameProcessor} into the first of
   * {@link RequestMappingHandlerAdapter#argumentResolvers}.
   *
   * @return BeanPostProcessor
   */
  @Bean
  public BeanPostProcessor beanPostProcessor() {
    return new BeanPostProcessor() {

      @Override
      public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        return bean;
      }

      @Override
      public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        if (bean instanceof RequestMappingHandlerAdapter) {
          RequestMappingHandlerAdapter adapter = (RequestMappingHandlerAdapter) bean;
          List<HandlerMethodArgumentResolver> argumentResolvers = new ArrayList<>(adapter.getArgumentResolvers());
          argumentResolvers.add(0, paramNameProcessor());
          adapter.setArgumentResolvers(argumentResolvers);
        }
        return bean;
      }
    };
  }

}

参数pojo:

@Data
public class Foo {

  private Integer id;

  @ParamName("first_name")
  private String firstName;

  @ParamName("last_name")
  private String lastName;

  @ParamName("created_at")
  @DateTimeFormat(pattern = "yyyy-MM-dd")
  private Date createdAt;

}

控制器方式:

@GetMapping("/foos")
public ResponseEntity<List<Foo>> listFoos(@RequestParam Foo foo, @PageableDefault(sort = "id") Pageable pageable) {
  List<Foo> foos = fooService.listFoos(foo, pageable);
  return ResponseEntity.ok(foos);
}

就这样。


这与@jkee的贡献有何不同?
弗朗斯

4

没有很好的内置方法可以执行此操作,您只能选择要应用的解决方法。处理之间的区别

@RequestMapping("/foo")
public String doSomethingWithJob(Job job)

@RequestMapping("/foo")
public String doSomethingWithJob(String stringjob)

是那个工作是一个bean,而stringjob不是(到目前为止还不足为奇)。真正的区别在于bean是使用标准的Spring bean解析器机制解析的,而字符串参数是由知道@RequestParam批注概念的Spring MVC解析的。长话短说,没有标准的Spring bean分辨率(即使用诸如PropertyValues,PropertyValue,GenericTypeAwarePropertyDescriptor之类的类)将“ jt”解析为名为“ jobType”的属性,或者至少我不知道。

解决方法可能就像其他人建议添加自定义PropertyEditor或过滤器一样,但是我认为这只是弄乱了代码。我认为最干净的解决方案是声明一个这样的类:

public class JobParam extends Job {
    public String getJt() {
         return super.job;
    }

    public void setJt(String jt) {
         super.job = jt;
    }

}

然后在控制器中使用它

@RequestMapping("/foo")
public String doSomethingWithJob(JobParam job) {
   ...
}

更新:

一个稍微简单的选择是不扩展,只需将额外的getter,setter添加到原始类中

public class Job {

    private String jobType;
    private String location;

    public String getJt() {
         return jobType;
    }

    public void setJt(String jt) {
         jobType = jt;
    }

}

@Bozho是的,它不太复杂,但至少易于阅读:)(我用简化的解决方案更新了原始帖子)
Peter Szanto 2012年

1
很简单,是的。很遗憾,春天不支持任何现成的方法=(
Vadim Kirilchuk 2015年

1
那不能解决原始问题。即使用Spring将包含连字符“ job-type”的连字符自动转换为DTO
Oscar Perez,

2

我想指出您另一个方向。但是我不知道它是否有效

我会尝试操纵绑定本身。

它是由方法完成的WebDataBinder,并将从HandlerMethodInvoker方法中调用Object[] resolveHandlerArguments(Method handlerMethod, Object handler, NativeWebRequest webRequest, ExtendedModelMap implicitModel) throws Exception

我对Spring 3.1并没有深入的了解,但是我看到的是Spring的这一部分已经进行了很多更改。因此,有可能交换WebDataBinder。在Spring 3.0中,如果不重写,就不可能进行接缝HandlerMethodInvoker


是的,这就是我现在要调查的地方。我认为我有一个
可行的

2

有一种简单的方法,您可以添加一个更多的setter方法,例如“ setLoc,setJt”。


带连字符的参数如何?Spring如何自动转换它们?
奥斯卡·佩雷斯

2

您可以使用Jackson com.fasterxml.jackson.databind.ObjectMapper将任何映射转换为带有嵌套道具的DTO / POJO类。您需要在嵌套对象上使用@JsonUnwrapped注释POJO。像这样:

public class MyRequest {

    @JsonUnwrapped
    private NestedObject nested;

    public NestedObject getNested() {
        return nested;
    }
}

而不是像这样使用它:

@RequestMapping(method = RequestMethod.GET, value = "/myMethod")
@ResponseBody
public Object myMethod(@RequestParam Map<String, Object> allRequestParams) {

    MyRequest request = new ObjectMapper().convertValue(allRequestParams, MyRequest.class);
    ...
}

就这样。一点编码。另外,您可以使用@JsonProperty给道具命名。


1

尝试使用拦截请求InterceptorAdaptor,然后使用简单的检查机制确定是否将请求转发给控制器处理程序。还要包装HttpServletRequestWrapper请求,以使您可以覆盖请求getParameter()

这样,您可以将实际的参数名称及其值重新传递回请求以供控制器查看。

示例选项:

public class JobInterceptor extends HandlerInterceptorAdapter {
 private static final String requestLocations[]={"rt", "jobType"};

 private boolean isEmpty(String arg)
 {
   return (arg !=null && arg.length() > 0);
 }

 public boolean preHandle(HttpServletRequest request,
   HttpServletResponse response, Object handler) throws Exception {

   //Maybe something like this
   if(!isEmpty(request.getParameter(requestLocations[0]))|| !isEmpty(request.getParameter(requestLocations[1]))
   {
    final String value =
       !isEmpty(request.getParameter(requestLocations[0])) ? request.getParameter(requestLocations[0]) : !isEmpty(request
        .getParameter(requestLocations[1])) ? request.getParameter(requestLocations[1]) : null;

    HttpServletRequest wrapper = new HttpServletRequestWrapper(request)
    {
     public String getParameter(String name)
     {
      super.getParameterMap().put("JobType", value);
      return super.getParameter(name);
     }
    };

    //Accepted request - Handler should carry on.
    return super.preHandle(request, response, handler);
   }

   //Ignore request if above condition was false
   return false;
   }
 }

最后HandlerInterceptorAdaptor,如下所示环绕控制器处理程序。将SelectedAnnotationHandlerMapping允许你指定哪个处理程序将被interecepted。

<bean id="jobInterceptor" class="mypackage.JobInterceptor"/>
<bean id="publicMapper" class="org.springplugins.web.SelectedAnnotationHandlerMapping">
    <property name="urls">
        <list>
            <value>/foo</value>
        </list>
    </property>
    <property name="interceptors">
        <list>
            <ref bean="jobInterceptor"/>
        </list>
    </property>
</bean>

编辑


目标方法只有1,它需要一个Job对象作为参数。这些字符串是参数,而不是位置
Bozho 2012年

处理程序方法采用Job对象,该对象与该preHandle方法持有的对象相同。因此,如上所述检查您的请求参数并返回true将导致控制器处理程序继续进行请求。
位图

我已经编辑了帖子,以显示如何拦截您的工作处理程序。
位图

还有,那将如何在Job对象上设置适当的参数?
博佐2012年

查看修改后的答案-可能会有所帮助。将“ HttpServletRequestWrapper”包装在请求周围,以使您可以重新传递参数名称和与其关联的值。
位图

1

jkee的答案有一点改进。

为了支持继承,您还应该分析父类。

/**
 * ServletRequestDataBinder which supports fields renaming using {@link ParamName}
 *
 * @author jkee
 * @author Yauhen Parmon
 */
public class ParamRenamingProcessor extends ServletModelAttributeMethodProcessor {

    @Autowired
    private RequestMappingHandlerAdapter requestMappingHandlerAdapter;

    //Rename cache
    private final Map<Class<?>, Map<String, String>> replaceMap = new ConcurrentHashMap<>();

    public ParamRenamingProcessor(boolean annotationNotRequired) {
       super(annotationNotRequired);
    }

    @Override
    protected void bindRequestParameters(WebDataBinder binder, NativeWebRequest nativeWebRequest) {
        Object target = binder.getTarget();
        Class<?> targetClass = Objects.requireNonNull(target).getClass();
        if (!replaceMap.containsKey(targetClass)) {
            replaceMap.put(targetClass, analyzeClass(targetClass));
        }
        Map<String, String> mapping = replaceMap.get(targetClass);
        ParamNameDataBinder paramNameDataBinder = new ParamNameDataBinder(target, binder.getObjectName(), mapping);
        Objects.requireNonNull(requestMappingHandlerAdapter.getWebBindingInitializer())
                .initBinder(paramNameDataBinder);    
        super.bindRequestParameters(paramNameDataBinder, nativeWebRequest);
    }

    private Map<String, String> analyzeClass(Class<?> targetClass) {
        Map<String, String> renameMap = new HashMap<>();
        for (Field field : targetClass.getDeclaredFields()) {
            ParamName paramNameAnnotation = field.getAnnotation(ParamName.class);
            if (paramNameAnnotation != null && !paramNameAnnotation.value().isEmpty()) {
               renameMap.put(paramNameAnnotation.value(), field.getName());
            }
        }
        if (targetClass.getSuperclass() != Object.class) {
            renameMap.putAll(analyzeClass(targetClass.getSuperclass()));
        }
        return renameMap;
    }
}

该处理器将分析以@ParamName注释的超类的字段。从initBinderSpring 5.0开始,它也不使用带有2个参数的方法。jkee回答中的所有其他内容都还可以。

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