Java Multithreading Import Data __java

Package cn.text;


Import java.util.ArrayList;
Import java.util.List;
Import Java.util.concurrent.CountDownLatch;
Import Java.util.concurrent.ExecutorService;
Import java.util.concurrent.Executors;


public class Text {



Test
public static void Main (string[] args) {
list<string> list = new arraylist<string> ();
The larger the data, the more threads
for (int i = 0; i < 3000000; i++) {
List.add ("Hello" +i);
}
try {
exec (list);
catch (Interruptedexception e) {
E.printstacktrace ();
}
}
public static void exec (List<string> List) throws interruptedexception{
int count = 300;//300 data for one thread processing
int listsize = List.size ();//data collection size
int runsize = (listsize/count) +1; Number of threads turned on
list<string> NewList = null;//Store execution data for each thread
Executorservice executor = Executors.newfixedthreadpool (runsize);//Create a thread pool with the same number as the number of open threads
Create two counters
Countdownlatch begin = New Countdownlatch (1);
Countdownlatch end = new Countdownlatch (runsize);
Looping to create a thread
for (int i = 0; i < runsize; i++) {
Calculate the data that each thread executes
if ((i+1) ==runsize) {
int startIndex = (i*count);
int endindex = List.size ();
Newlist= list.sublist (StartIndex, endindex);
}else{
int startIndex = (i*count);
int endindex = (i+1) *count;
Newlist= list.sublist (StartIndex, endindex);
}
Thread class
Mythread mythead = new Mythread (newlist,begin,end);
The way the thread is executed here is the Executor.execute (Mythead) method of the calling line Cheng Chili.
Executor.execute (Mythead);
}

Begin.countdown ();
End.await ();

Finish closing the thread pool
Executor.shutdown ();
}
Thread classes are not written separately, written in the same file, there is a need to write separately
private static class Mythread implements runnable{
Private list<string> List;
Private Countdownlatch begin;
Private Countdownlatch end;

Create a constructor initialization list, and other parameters used
Public Mythread (list<string> list,countdownlatch Begin,countdownlatch end) {
This.list = list;
This.begin = begin;
This.end = end;
}

@Override
public void Run () {
try {
for (int i = 0; i < list.size (); i++) {
Here again, because in the real project, when the data being processed has a wait timeout and an error causes the thread to remain in the waiting state
This is just a simple process,
System.out.println (List.get (i));
}
//....
Run the thread straight into the wait
Begin.await ();
catch (Interruptedexception e) {
TODO auto-generated Catch block
E.printstacktrace ();
}finally{
Here is the main, when a thread is done counting to reduce a don't this thread will be hung all the time
, End.countdown (), this method is to directly reduce the counter by one
End.countdown ();
}
}


}



}