真香警告！扩展 swagger支持文档自动列举所有枚举值
承接上篇文章 《一站式解决使用枚举的各种痛点》 文章最后提到：在使用 swagger 来编写接口文档时，需要告诉前端枚举类型有哪些取值，每次增加取值之后，不仅要改代码，还要找到对应的取值在哪里使用了，然后修改 swagger 文档。反正小黑我觉得这样做很不爽，那有没有什么办法可以让 swagger 框架来帮我们自动列举出所有的枚举数值呢？
这期小黑同学就来讲讲解决方案。
先来看一下效果，有一个感性的认识
请注意哦，这里是课程类型不是我们手动列举出来的，是swagger框架帮我们自动列举的。对应的代码如下：
那么，这是怎么做到的呢？
简单描述一下实现：
1、自定义 SwaggerDisplayEnum 注解，注解中有两个属性，这两个属性是用来干什么的呢？小黑我先不说，大家往下阅读，相信就能明白啦~
@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface SwaggerDisplayEnum {
String index() default "index";
String name() default "name";
}
2、在我们的自定义枚举类中标记 @SwaggerDisplayEnum 注解
@Getter
@AllArgsConstructor
@SwaggerDisplayEnum(index = "type", name = "desc")
public enum CourseType {
/**
* 图文
*/
PICTURE(102, "图文"),
/**
* 音频
*/
AUDIO(103, "音频"),
/**
* 视频
*/
VIDEO(104, "视频"),
/**
* 外链
*/
URL(105, "外链"),
;
@JsonValue
private final int type;
private final String desc;
private static final Map<Integer, CourseType> mappings;
static {
Map<Integer, CourseType> temp = new HashMap<>();
for (CourseType courseType : values()) {
temp.put(courseType.type, courseType);
}
mappings = Collections.unmodifiableMap(temp);
}
@EnumConvertMethod
@JsonCreator(mode = JsonCreator.Mode.DELEGATING)
@Nullable
public static CourseType resolve(int index) {
return mappings.get(index);
}
}
3、实现 ModelPropertyBuilderPlugin 接口，扩展 swagger，实现在文档中列举所有的枚举值。
public class EnumModelPropertyBuilderPlugin implements ModelPropertyBuilderPlugin {
@Override
public void apply(ModelPropertyContext context) {
Optional<BeanPropertyDefinition> optional = context.getBeanPropertyDefinition();
if (!optional.isPresent()) {
return;
}
final Class<?> fieldType = optional.get().getField().getRawType();
addDescForEnum(context, fieldType);
}
@Override
public boolean supports(DocumentationType delimiter) {
return true;
}
private void addDescForEnum(ModelPropertyContext context, Class<?> fieldType) {
if (Enum.class.isAssignableFrom(fieldType)) {
SwaggerDisplayEnum annotation = AnnotationUtils.findAnnotation(fieldType, SwaggerDisplayEnum.class);
if (annotation != null) {
String index = annotation.index();
String name = annotation.name();
Object[] enumConstants = fieldType.getEnumConstants();
List<String> displayValues =
Arrays.stream(enumConstants)
.filter(Objects::nonNull)
.map(item -> {
Class<?> currentClass = item.getClass();
Field indexField = ReflectionUtils.findField(currentClass, index);
ReflectionUtils.makeAccessible(indexField);
Object value = ReflectionUtils.getField(indexField, item);
Field descField = ReflectionUtils.findField(currentClass, name);
ReflectionUtils.makeAccessible(descField);
Object desc = ReflectionUtils.getField(descField, item);
return value + ":" + desc;
}).collect(Collectors.toList());
ModelPropertyBuilder builder = context.getBuilder();
Field descField = ReflectionUtils.findField(builder.getClass(), "description");
ReflectionUtils.makeAccessible(descField);
String joinText = ReflectionUtils.getField(descField, builder)
+ " (" + String.join("; ", displayValues) + ")";
builder.description(joinText).type(context.getResolver().resolve(Integer.class));
}
}
}
}
4、实现 ParameterBuilderPlugin 和 OperationBuilderPlugin 接口，列举枚举参数的所有取值。
public class EnumParameterBuilderPlugin implements ParameterBuilderPlugin, OperationBuilderPlugin {
private static final Joiner joiner = Joiner.on(",");
@Override
public void apply(ParameterContext context) {
Class<?> type = context.resolvedMethodParameter().getParameterType().getErasedType();
if (Enum.class.isAssignableFrom(type)) {
SwaggerDisplayEnum annotation = AnnotationUtils.findAnnotation(type, SwaggerDisplayEnum.class);
if (annotation != null) {
String index = annotation.index();
String name = annotation.name();
Object[] enumConstants = type.getEnumConstants();
List<String> displayValues = Arrays.stream(enumConstants).filter(Objects::nonNull).map(item -> {
Class<?> currentClass = item.getClass();
Field indexField = ReflectionUtils.findField(currentClass, index);
ReflectionUtils.makeAccessible(indexField);
Object value = ReflectionUtils.getField(indexField, item);
Field descField = ReflectionUtils.findField(currentClass, name);
ReflectionUtils.makeAccessible(descField);
Object desc = ReflectionUtils.getField(descField, item);
return value.toString();
}).collect(Collectors.toList());
ParameterBuilder parameterBuilder = context.parameterBuilder();
AllowableListValues values = new AllowableListValues(displayValues, "LIST");
parameterBuilder.allowableValues(values);
}
}
}
@Override
public boolean supports(DocumentationType delimiter) {
return true;
}
@Override
public void apply(OperationContext context) {
Map<String, List<String>> map = new HashMap<>();
List<ResolvedMethodParameter> parameters = context.getParameters();
parameters.forEach(parameter -> {
ResolvedType parameterType = parameter.getParameterType();
Class<?> clazz = parameterType.getErasedType();
if (Enum.class.isAssignableFrom(clazz)) {
SwaggerDisplayEnum annotation = AnnotationUtils.findAnnotation(clazz, SwaggerDisplayEnum.class);
if (annotation != null) {
String index = annotation.index();
String name = annotation.name();
Object[] enumConstants = clazz.getEnumConstants();
List<String> displayValues = Arrays.stream(enumConstants).filter(Objects::nonNull).map(item -> {
Class<?> currentClass = item.getClass();
Field indexField = ReflectionUtils.findField(currentClass, index);
ReflectionUtils.makeAccessible(indexField);
Object value = ReflectionUtils.getField(indexField, item);
Field descField = ReflectionUtils.findField(currentClass, name);
ReflectionUtils.makeAccessible(descField);
Object desc = ReflectionUtils.getField(descField, item);
return value + ":" + desc;
}).collect(Collectors.toList());
map.put(parameter.defaultName().or(""), displayValues);
OperationBuilder operationBuilder = context.operationBuilder();
Field parametersField = ReflectionUtils.findField(operationBuilder.getClass(), "parameters");
ReflectionUtils.makeAccessible(parametersField);
List<Parameter> list = (List<Parameter>) ReflectionUtils.getField(parametersField, operationBuilder);
map.forEach((k, v) -> {
for (Parameter currentParameter : list) {
if (StringUtils.equals(currentParameter.getName(), k)) {
Field description = ReflectionUtils.findField(currentParameter.getClass(), "description");
ReflectionUtils.makeAccessible(description);
Object field = ReflectionUtils.getField(description, currentParameter);
ReflectionUtils.setField(description, currentParameter, field + " , " + joiner.join(v));
break;
}
}
});
}
}
});
}
}
这篇文章比较枯燥，小黑我也不知道该怎么去讲述，只是将源码附录了出来。如果有读者看了之后还是不清楚的话，可以给我留言，我会一一解答。感谢你的阅读~~
相关源码已经上传到了 github：https://github.com/shenjianeng/solution-for-enums
