springmvc对出参和入参有非常友好的拓展支持,方便你对数据的输入和输出有更大的执行权，我们如何通过springmvc定义的结果做一系列处理呢？
入参
requestbodyadvice : 针对所有以@requestbody的参数做处理
参考案例 : jsonviewrequestbodyadvice
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public class jsonviewrequestbodyadvice extends requestbodyadviceadapter {
/**
* 这里是一个前置拦截匹配操作,其实就是告诉你满足为true的才会执行下面的beforebodyread方法,这里可以定义自己业务相关的拦截匹配
* @param methodparameter
* @param targettype
* @param convertertype
* @return
*/
@override
public boolean supports(methodparameter methodparameter, type targettype,
class<? extends httpmessageconverter<?>> convertertype) {
return (abstractjackson2httpmessageconverter.class.isassignablefrom(convertertype) &&
methodparameter.getparameterannotation(jsonview.class) != null);
}
// 这里就是具体的前置操作了... 下面的例子就是查找这个入参方法是否有@jsonview修饰
@override
public httpinputmessage beforebodyread(httpinputmessage inputmessage, methodparameter methodparameter,
type targettype, class<? extends httpmessageconverter<?>> selectedconvertertype) throws ioexception {
jsonview annotation = methodparameter.getparameterannotation(jsonview.class);
class<?>[] classes = annotation.value();
if (classes.length != 1) {
throw new illegalargumentexception(
"@jsonview only supported for request body advice with exactly 1 class argument: " + methodparameter);
}
return new mappingjacksoninputmessage(inputmessage.getbody(), inputmessage.getheaders(), classes[0]);
}
}
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出参
responsebodyadvice: 针对所有以@responsebody的参数做处理
参考案例:
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@controlleradvice
public class logresponsebodyadvice implements responsebodyadvice {
/**
*
* @param returntype
* @param convertertype
* @return
*/
@override
public boolean supports(methodparameter returntype, class convertertype) {
return true;
}
@override
public object beforebodywrite(object body, methodparameter returntype, mediatype selectedcontenttype, class selectedconvertertype, serverhttprequest request, serverhttpresponse response) {
// 做任何事情 body 就是返回的结果对象,没有处理之前
return body;
}
}
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注意事项
自定义的处理对象类上必须得加上@controlleradvice注解!
为什么?
源码中requestmappinghandleradapter类在执行initcontrolleradvicecache()做初始化的时候会执行一个
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list<controlleradvicebean> beans = controlleradvicebean.findannotatedbeans(getapplicationcontext());
annotationawareordercomparator.sort(beans);
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而controlleradvicebean.findannotatedbeans方法会查找类上有controlleradvice注解的类才会加入到处理当中..
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public static list<controlleradvicebean> findannotatedbeans(applicationcontext applicationcontext) {
list<controlleradvicebean> beans = new arraylist<controlleradvicebean>();
for (string name : beanfactoryutils.beannamesfortypeincludingancestors(applicationcontext, object.class)) {
if (applicationcontext.findannotationonbean(name, controlleradvice.class) != null) {
beans.add(new controlleradvicebean(name, applicationcontext));
}
}
return beans;
}
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所以大家可以根据自己的需要,定义结果的入参和出参结果做一些特殊处理.....
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：https://www.jianshu.com/p/5d3f701d4fc3