Chapter 1 Introduction and use skills of interceptors

1-1 Interceptor Getting started with interceptors

 

  Demonstrate one by one

Create a project

  take restful Copy the code from , Easy to demonstrate

open xml Increased reliance on

 provided Only in the development and compilation will reference , When packaging for final use jar Will be excluded

Add interceptor package

 

  Generate three methods

 

 

  Why introduce the dependency just now ？

because

  These three methods all point to native request and response object , If you do not introduce dependent programs, you will report compilation errors

 return true It will be delivered to the later interceptor or controller ,false It will directly return to the client , The result determines whether to continue execution or end immediately and return the response back , This is very important for program control

  After the target resource is processed successfully , But before the response text is generated , What to do

  After the corresponding text of the target is generated , That's how it works

  stay applicationContext Configure in to make springmvc To identify

  Intercept all requests , Then the intercepted request is delivered to Myinterceptor And execute it in the sequence of the implementation methods inside

function

The response returns success , View console

  This sentence is increasing  

 1-2 Interceptor Using skills

  There will be many problems to be solved in actual use

start-up

  But the controller prints out a lot of extra information

  Every time you send localhost This url Its essence is through tomcat To call springmvc The parsing function of , To get the corresponding resources , These resources are in line with /** All rules will be blocked

  The interceptor is not affected by this sentence

  Exclude some static addresses

  Run again

  At this time, only client.html Captured

There are too many static types , If you configure one by one like the above, it may be a long time , How to make us understand static resources and controller Applications are effectively differentiated ？

Unified management of static resources

By managing the static resource directory to uniformly exclude these  

  Reverse thinking is also possible, such as only restful Intercept all requests under

 

  If more than one is needed uri Where to intercept , Additional writing  

If a request is filtered by multiple interceptors at the same time , Which one is the first to execute ？

increase myinterceptor1

  Configure the new interceptor

  Two interceptors work uri It's the same , That's first ？ What about execution later ？、

  The order is reversed , Why? ？

 return false What happens when an interrupt occurs ？

 

  The request that should be executed and subsequent processing are all blocked , At the same time, the response is all produced in the current method

Pass in an array to test

 

  What you get in the corresponding part of the request is the response text generated in the interceptor

1-3 Inteceptor and Filter The difference between