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eter, exMsg));
}
}
throw ex;
}
}
return args;
}
// 最终会使用AbstractNamedValueMethodArgumentResolver来进行处理
public final Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory) throws Exception {
NamedValueInfo namedValueInfo = getNamedValueInfo(parameter);
MethodParameter nestedParameter = parameter.nestedIfOptional();
// 得到请求参数名称为"localdate"
Object resolvedName = resolveEmbeddedValuesAndExpressions(namedValueInfo.name);
if (resolvedName == null) {
throw new IllegalArgumentException(
"Specified name must not resolve to null: [" + namedValueInfo.name + "]");
}
// 获取请求的locadate的值，此时为字符串格式"yyyy-mm-dd"
Object arg = resolveName(resolvedName.toString(), nestedParameter, webRequest);
if (arg == null) {
if (namedValueInfo.defaultValue != null) {
arg = resolveEmbeddedValuesAndExpressions(namedValueInfo.defaultValue);
}
else if (namedValueInfo.required && !nestedParameter.isOptional()) {
handleMissingValue(namedValueInfo.name, nestedParameter, webRequest);
}
arg = handleNullValue(namedValueInfo.name, arg, nestedParameter.getNestedParameterType());
}
else if ("".equals(arg) && namedValueInfo.defaultValue != null) {
arg = resolveEmbeddedValuesAndExpressions(namedValueInfo.defaultValue);
}
// 这里就会使用bindFactory进行处理
if (binderFactory != null) {
WebDataBinder binder = binderFactory.createBinder(webRequest, null, namedValueInfo.name);
try {
// 经过这里进行处理，输入的string类型就会转为LocalDate了
arg = binder.convertIfNecessary(arg, parameter.getParameterType(), parameter);
}
catch (ConversionNotSupportedException ex) {
throw new MethodArgumentConversionNotSupportedException(arg, ex.getRequiredType(),
namedValueInfo.name, parameter, ex.getCause());
}
catch (TypeMismatchException ex) {
throw new MethodArgumentTypeMismatchException(arg, ex.getRequiredType(),
namedValueInfo.name, parameter, ex.getCause());
}
// Check for null value after conversion of incoming argument value
if (arg == null && namedValueInfo.defaultValue == null &&
namedValueInfo.required && !nestedParameter.isOptional()) {
handleMissingValueAfterConversion(namedValueInfo.name, nestedParameter, webRequest);
}
}
handleResolvedValue(arg, namedValueInfo.name, parameter, mavContainer, webRequest);
return arg;
}
最后附上上面调用过程中一些类的介绍
以上就是ControllerAdivce的全介绍。通过对源码的学习，加深了对HTTP请求过程的理解。
参考:https://blog.csdn.net/zmm__1377445292/article/details/116158554
作者：京东物流 付鹏嘎
来源：京东云开发者社区 自猿其说Tech
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