filter
新建 timefilter
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@component
public class timefilter implements filter {
@override
public void init(filterconfig filterconfig) throws servletexception {
system.out.println("time filter init");
}
@override
public void dofilter(servletrequest servletrequest, servletresponse servletresponse, filterchain filterchain) throws ioexception, servletexception {
system.out.println("time filter start");
long starttime = system.currenttimemillis();
filterchain.dofilter(servletrequest, servletresponse);
long endtime = system.currenttimemillis();
system.out.println("time filter consume " + (endtime - starttime) + " ms");
system.out.println("time filter end");
}
@override
public void destroy() {
system.out.println("time filter init");
}
}
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启动服务器，在浏览器输入：http://localhost:8080/hello?name=tom
可以在控制台输出如下结果：
time filter start
name: tom
time filter consume 3 ms
time filter end
可以看到，filter 先执行，再到真正执行 hellocontroller.sayhello() 方法。
通过 timefilter.dofilter(servletrequest servletrequest, servletresponse servletresponse, filterchain filterchain) 方法的参数可以看出，我们只能得到原始的 request 和 response对象，不能得到这个请求被哪个 controller 以及哪个方法处理了，使用interceptor 就可以获得这些信息。
interceptor
新建 timeinterceptor
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@component
public class timeinterceptor extends handlerinterceptoradapter {
private final namedthreadlocal<long> starttimethreadlocal = new namedthreadlocal<>("starttimethreadlocal");
@override
public boolean prehandle(httpservletrequest request, httpservletresponse response, object handler) throws exception {
system.out.println("time interceptor prehandle");
handlermethod handlermethod = (handlermethod) handler;
// 获取处理当前请求的 handler 信息
system.out.println("handler 类：" + handlermethod.getbeantype().getname());
system.out.println("handler 方法：" + handlermethod.getmethod().getname());
methodparameter[] methodparameters = handlermethod.getmethodparameters();
for (methodparameter methodparameter : methodparameters) {
string parametername = methodparameter.getparametername();
// 只能获取参数的名称，不能获取到参数的值
//system.out.println("parametername: " + parametername);
}
// 把当前时间放入 threadlocal
starttimethreadlocal.set(system.currenttimemillis());
return true;
}
@override
public void posthandle(httpservletrequest request, httpservletresponse response, object handler, modelandview modelandview) throws exception {
system.out.println("time interceptor posthandle");
}
@override
public void aftercompletion(httpservletrequest request, httpservletresponse response, object handler, exception ex) throws exception {
// 从 threadlocal 取出刚才存入的 starttime
long starttime = starttimethreadlocal.get();
long endtime = system.currenttimemillis();
system.out.println("time interceptor consume " + (endtime - starttime) + " ms");
system.out.println("time interceptor aftercompletion");
}
}
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注册 timeinterceptor
把 timeinterceptor 注入 spring 容器
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@configuration
public class webconfig extends webmvcconfigureradapter {
@autowired
private timeinterceptor timeinterceptor;
@override
public void addinterceptors(interceptorregistry registry) {
registry.addinterceptor(timeinterceptor);
}
}
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启动服务器，在浏览器输入：http://localhost:8080/hello?name=tom
可以在控制台输出如下结果：
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time filter start
time interceptor prehandle
handler 类：com.nextyu.demo.web.controller.hellocontroller
handler 方法：sayhello
name: tom
time interceptor posthandle
time interceptor consume 40 ms
time interceptor aftercompletion
time filter consume 51 ms
time filter end
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可以看到，filter 先于 interceptor 执行，再到真正执行 hellocontroller.sayhello() 方法。通过 interceptor 方法上的 handler 参数，我们就可以得到这个请求被哪个 controller 以及哪个方法处理了。但是不能直接获取到这个方法上的参数值（在这里就是 hellocontroller.sayhello(string name) 方法参数 name 的值），通过 aspect 就可以获取到。
aspcet
新建 timeaspect
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@aspect
@component
public class timeaspect {
@around("execution(* com.nextyu.demo.web.controller.*.*(..))")
public object handlecontrollermethod(proceedingjoinpoint pjp) throws throwable {
system.out.println("time aspect start");
object[] args = pjp.getargs();
for (object arg : args) {
system.out.println("arg is " + arg);
}
long starttime = system.currenttimemillis();
object object = pjp.proceed();
long endtime = system.currenttimemillis();
system.out.println("time aspect consume " + (endtime - starttime) + " ms");
system.out.println("time aspect end");
return object;
}
}
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启动服务器，在浏览器输入：http://localhost:8080/hello?name=tom
可以在控制台输出如下结果：
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time filter start
time interceptor prehandle
handler 类：com.nextyu.demo.web.controller.hellocontroller
handler 方法：sayhello
time aspect start
arg is tom
name: tom
time aspect consume 0 ms
time aspect end
time interceptor posthandle
time interceptor consume 2 ms
time interceptor aftercompletion
time filter consume 4 ms
time filter end
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可以看到，filter 先执行，再到 interceptor 执行，再到 aspect 执行，再到真正执行 hellocontroller.sayhello() 方法。
我们也获取到了 hellocontroller.sayhello(string name) 方法参数 name 的值。
请求拦截过程图
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graph td
httprequest-->filter
filter-->interceptor
interceptor-->aspect
aspect-->controller
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