java threadlocal

Why ThreadLocal? In any case, to write a multithreaded security (Thread-safe) program is difficult, in order to allow the thread to share resources, must be careful to synchronize the shared resources, synchronization brings certain performance delays, on the other hand, in the process of synchronization, but also attention to the lock and release of objects, to avoid the deadlock, All sorts of factors make it difficult to write multithreaded programm

the other thread independent of the initialized copy of the variable , threadlocal can give an initial value, and each thread will get a copy of the initialization value to ensure that different threads have a copy. The state is associated with a thread , and ThreadLocal is not used to solve the problem of shared variables, not to reconcile thread synchronization, but to introduce a mechanism to fa

key stored in the map, and the value entered by the user is values.It's too messy. It's not clear, draw a picture to see (see Figure 5-7).Simply put, this map object exists as a private variable inside thread, so it is thread-safe. Threadlocal gets the current thread by Thread.CurrentThread () to get the map object. At the same time, it initiates writes and reads itself as a key, because it takes itself as a key, so that a

, threadlocal assigns a separate copy of the variable to each thread that uses the variable. So each thread can change its own copy independently, without affecting the copy of the other thread. from the thread's point of view, this variable is like a thread's local variable, which is the meaning of the "local" in the class name.Thread-local variables are not a new Java invention, and many languages (such a

, if E is not null and key is the same return e;2, if E is null or key inconsistency is queried to the next location, if the next key and the current need to query the key is equal, then the corresponding entry is returned, otherwise, if the key value is null, then the location of the entry is erased, otherwise continue to the next location query. In this process encountered the key is NULL entry will be erased, then the value within the entry will not have a strong reference chain, will natural

affects system performance. In addition, it is very challenging to solve thread security through code synchronization, which may increase the implementation difficulty several times. What kind of magic does the template rely on to solve the thread security problem without thread synchronization? The answer is ThreadLocal!ThreadLocal plays an important role in Spring. It has appeared in Bean, transaction ma

The threadlocal differs from the thread member variable, threadlocal This class provides a thread-local variable. This local variable is not the same as the general member variable, threadlocal variables are used by multiple threads, each thread can only get a copy of the variable, which is described in the Java API, t

ThreadLocal in Java is another-achieve thread-safety apart from writing immutable classes. If you had been writing multi-threaded or concurrent code in Java then you must being familiar with cost of synchronization or locking which can greatly affect Scalability of application, but there was no choice other than synchronize if you are S Haring objects between mul

Brief introductionAs early as the version of JDK 1.2, Java.lang.threadlocal,threadlocal provides a new way to solve the concurrency problem of multi-threaded threads. Using this tool class, you can write beautiful multithreaded programs very concisely. When you use threadlocal to maintain variables, Threadlocal provides a separate copy of the variable for each th

Introduction to the ThreadLocal class in Java, javathreadlocal First, we must make it clear that ThreadLocal is not a multi-threaded class, or it should be called a local variable of the thread. This can be seen from the JDK definition of ThreadLocal. public class ThreadLocal