6.ThreadLocal Class and application skills

1 ImportJava.util.Random;2 3 /**4 * Threadlocal class and application skills5  * *******************************************************************6 * Each thread invokes the set method of the global Threadlocal object, which is equivalent to adding a record to its internal map, key7 * respectively is the respective thread, values is the value that the respective set method wears in. Threadlocal.clear () can be called at the end of the thread;8 * method, which frees up memory faster and does not call, because the associated threadlocal variable can also be freed automatically after the thread ends. 9 * Implement the encapsulation of the threadlocal variable, so that the outside world does not directly manipulate the threadlocal variableTen * This application is relatively rare in the encapsulation of basic types of data.  One * Encapsulation of data of an object type, which is more common, is to have a class create a separate instance object for different threads, respectively.  A * Summary: - * A threadlocal represents a variable, so it can only put one data, you have two variables to be within the thread range - * Shared, you define two Threadlocal objects. What if there are 100 variables to be shared by the thread? Package The threadlocal the * into one singleton class.  -  *  - * The thought in Struts2 is threadlocal mode -  *  +  * ******************************************************************* - * Register hook notification when virtual machine hangs + * Runtime->addshutdownhook (Thread hook) A  * @authorlitaiqing at  */ -  Public classThreadlocaltest { -     Private StaticThreadlocal<integer> ThreadLocal =NewThreadlocal<integer>(); -     //private static threadlocal<mythreadscopedata> Mythreadscopedata = new threadlocal<mythreadscopedata> (); -      Public Static voidMain (string[] args) { -          for(inti = 0; I < 2; i++){ in             NewThread (NewRunnable () { - @Override to                  Public voidrun () { +                     intdata =NewRandom (). Nextint (); -System.out.println (Thread.CurrentThread (). GetName () + "Get put data:" +data); the threadlocal.set (data); *                     //Mythreadscopedata.set (New Mythreadscopedata ("name" +data,data)); $Mythreadscopedata.getthreadinstance (). SetName ("name" +data);Panax Notoginseng mythreadscopedata.getthreadinstance (). setage (data); -                     NewA (). get (); the                     NewB (). get (); +                 } A }). Start (); the         } +     } -     Static classa{ $          Public voidget () { $             intdata =threadlocal.get (); -System.out.println ("A from" + Thread.CurrentThread (). GetName () + "Get put data:" +data); -             //Mythreadscopedata myData = Mythreadscopedata.get (); theMythreadscopedata MyData =mythreadscopedata.getthreadinstance (); -System.out.println ("A from" + Thread.CurrentThread (). GetName () + "Getmydata:" + mydata.getname () + "," +mydata.getage ());Wuyi         } the     } -     Static classb{ Wu          Public voidget () { -             intdata =threadlocal.get (); AboutSystem.out.println ("B from" + Thread.CurrentThread (). GetName () + "Get put data:" +data); $             //Mythreadscopedata myData = Mythreadscopedata.get (); -Mythreadscopedata MyData =mythreadscopedata.getthreadinstance (); -System.out.println ("B from" + Thread.CurrentThread (). GetName () + "Getmydata:" + mydata.getname () + "," +mydata.getage ()); -         } A     } + } the classmythreadscopedata{ -     Private Staticthreadlocal<mythreadscopedata> map =NewThreadlocal<mythreadscopedata>(); $     //private static Mythreadscopedata instance = null;//new Mythreadscopedata (); the      the     PrivateMythreadscopedata () {}; the     /** the * This can be used without synchronized, because it is located in different lines range are stored in threadlocal -      * @return in      */ the      Public Static /*synchronized*/mythreadscopedata getthreadinstance () { theMythreadscopedata instance =map.get (); About         //This approach is prone to multithreading concurrency problems. So it's best to use a hungry man mode the         if(instance==NULL){ theInstance =NewMythreadscopedata (); the Map.set (instance); +         } -         returninstance; the     }Bayi      the     PrivateString name; the     Private intAge ; -      - //Public Mythreadscopedata (String name, int.) { the //super (); the //this.name = name; the //this.age = age; the //    } -      PublicString GetName () { the         returnname; the     } the      Public voidsetName (String name) {94          This. Name =name; the     } the      Public intGetage () { the         returnAge ;98     } About      Public voidSetage (intAge ) { -          This. Age =Age ;101     }102}

6.ThreadLocal Class and application skills