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学习记录：DAY28

news 来源：原创 2025/5/10 8:38:24

DispatcherController 功能完善与接口文档编写

前言

没什么动力说废话了。
今天来完善 DispatcherController 的功能，然后写写接口文档。

日程

早上：本来只有早八，但是早上摸鱼了，罪过罪过。
下午：把 DispatcherController 完善得比较充足了（我认为的哈）。
晚上 10 点：现在的时间，deepseek 卡爆了，先来写写 blog。
晚上 10 点半：摆烂了，开摆！

学习内容

省流

DispatcherController 完善

1. `DispatcherController` 完善（有点水了）

主要是兼容各种询问参数，注解如下：

@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
public @interface KatPathVariable {String value() default "";
}@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
public @interface KatRequestBody {boolean required() default true;
}@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
public @interface KatRequestParam {String value() default "";  // 参数名boolean required() default true;  // 是否必须String defaultValue() default "";  // 默认值
}

1）路径参数 `KatPathVariable`

private Object resolvePathVariable(KatPathVariable annotation,java.lang.reflect.Parameter parameter,Class<?> paramType,HttpServletRequest req) {Map<String, String> pathVariables = (Map<String, String>) req.getAttribute("pathVariables");// 获取参数名，优先使用注解值，其次使用参数名String paramName = annotation.value().isEmpty()? parameter.getName(): annotation.value();String value = pathVariables.get(paramName);if (value == null) {throw new IllegalArgumentException("Path variable '" + paramName + "' not found");}try {// 使用 TypeConverter 进行类型转换return TypeConverter.convertValue(value, paramType);} catch (IllegalArgumentException e) {throw new IllegalArgumentException(String.format("Failed to convert path variable '%s' value '%s' to type %s",paramName, value, paramType.getName()),e);}
}

TypeConverter 是从原来 SimpleMapper 类中拆出来的方法：

public static Object convertValue(Object value, Class<?> targetType) {if (value == null) {if (targetType == Number.class) { // Number类型检查return 0;}return null;}if (targetType.isInstance(value)) {return value;}// 数值类型转换if (value instanceof Number number) {if (targetType == Double.class || targetType == double.class) {return number.doubleValue();}if (targetType == Float.class || targetType == float.class) {return number.floatValue();}if (targetType == Integer.class || targetType == int.class) {return number.intValue();}// 其他数值类型省略...}// 字符串到其他类型的转换if (value instanceof String strValue) {try {if (targetType == Integer.class || targetType == int.class) {return Integer.parseInt(strValue);}if (targetType == Long.class || targetType == long.class) {return Long.parseLong(strValue);}// 其他类型省略...} catch (NumberFormatException e) {throw new IllegalArgumentException("Failed to convert string '" + strValue +"' to type " + targetType.getName(), e);}}// 日期类型转换if (value instanceof java.sql.Date sqlDate) {if (targetType == LocalDate.class) {return sqlDate.toLocalDate();}if (targetType == LocalDateTime.class) {return sqlDate.toLocalDate().atStartOfDay();}}// 布尔类型转换、时间戳转换等省略...log.warn("Cannot convert value '{}' of type {} to target type {}",value, value.getClass().getName(), targetType.getName());throw new IllegalArgumentException("Cannot convert value '" + value +"' of type " + value.getClass().getName() +" to target type " + targetType.getName());
}

2）询问参数 `KatRequestParam`

也是差不多的逻辑：

private Object resolveRequestParam(KatRequestParam annotation,java.lang.reflect.Parameter parameter,Class<?> paramType,HttpServletRequest req) {// 获取参数名，优先使用注解值，其次使用参数名String paramName = annotation.value().isEmpty()? parameter.getName(): annotation.value();String paramValue = req.getParameter(paramName);// 处理参数缺失情况if (paramValue == null || paramValue.isEmpty()) {if (annotation.required()) {throw new IllegalArgumentException("Required request parameter '" + paramName + "' is not present");}if (!annotation.defaultValue().isEmpty()) {paramValue = annotation.defaultValue();} else {return null; // 非必需且无默认值，返回null}}try {// 使用 TypeConverter 进行类型转换return TypeConverter.convertValue(paramValue, paramType);} catch (IllegalArgumentException e) {throw new IllegalArgumentException(String.format("Failed to convert request parameter '%s' value '%s' to type %s",paramName, paramValue, paramType.getName()),e);}
}

3）请求体参数 `KatRequestBody`

private Object resolveRequestBody(Class<?> paramType,HttpServletRequest req,KatRequestBody annotation) throws IOException {// 检查请求体是否为空if (req.getContentLength() == 0) {if (annotation.required()) {throw new IllegalArgumentException("Required request body is missing");}return null;}try {String requestBody = ServletUtils.getRequestBody(req); // 如果是String类型，直接返回if (paramType.equals(String.class)) {return requestBody;}// 构建对象return JsonUtils.parseJson(requestBody, paramType); //这里借助了Jakson工具} catch (Exception e) {throw new IllegalArgumentException("Failed to parse request body", e);}
}

4）对应代理方法的装配也有比较大的改动

private Object invokeHandlerMethod(HandlerMethod handler,HttpServletRequest req,HttpServletResponse resp) throws Exception {Method method = handler.method();Object[] args = new Object[method.getParameterCount()];Class<?>[] paramTypes = method.getParameterTypes();Annotation[][] paramAnnotations = method.getParameterAnnotations(); //一个for (int i = 0; i < paramTypes.length; i++) {// 处理 @KatPathVariable 注解参数KatPathVariable pathVar = findAnnotation(paramAnnotations[i],KatPathVariable.class);if (pathVar != null) {args[i] = resolvePathVariable(pathVar, method.getParameters()[i],paramTypes[i], req);continue;}// 处理 @KatRequestParam 注解参数KatRequestParam requestParam = findAnnotation(paramAnnotations[i], KatRequestParam.class);if (requestParam != null) {args[i] = resolveRequestParam(requestParam,method.getParameters()[i], paramTypes[i], req);continue;}// 处理 @KatRequestBody 注解参数KatRequestBody requestBody = findAnnotation(paramAnnotations[i], KatRequestBody.class);if (requestBody != null) {args[i] = resolveRequestBody(paramTypes[i], req, requestBody);continue;}// 处理 HttpServletRequest/HttpServletResponse 参数if (paramTypes[i].equals(HttpServletRequest.class)) {args[i] = req;} else if (paramTypes[i].equals(HttpServletResponse.class)) {args[i] = resp;}}return method.invoke(handler.controllerInstance(), args);
}