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嗨，大家好，我正在嘗試使用線程池對二維數組進行排序來測量執行時間，並在增加線程數和數組中元素總數時進行比較。我做了一些編碼，但顯然它運行速度很慢，出於某種原因，我得到空指針異常。我認爲原因在於使用Integer數組，因爲Callable不能使用原始的int []數組。幫助將非常理解如何使用線程池和Callable接口對二維數組進行排序？
public class MatrixBubbleSort {
public static void main(String[] args) throws InterruptedException, ExecutionException {
MatrixBubbleSort obj = new MatrixBubbleSort();
String resultMatrix = "";
resultMatrix = obj.sort2D();
System.out.println(resultMatrix);
}
public String sort2D() throws InterruptedException, ExecutionException {
long start = 0;
long end = 0;
int rows = 5;
int cols = 5;
Integer[][] matrix = new Integer[rows][cols];
Future<Integer[]>[] returned;
returned = new Future[rows];
Sorter[] tasks = new Sorter[rows];
ExecutorService executer = Executors.newFixedThreadPool(5);
for(int r = 0; r< rows; r++){
for(int c = 0; c < cols; cols++){
matrix[r][c] = (int) (Math.random() * (rows*cols));
}
}
System.out.print(printArr(matrix) + "\n");
start = System.currentTimeMillis();
for(int r = 0; r< rows; r++){
tasks[r] = new Sorter(matrix[r]);
returned[r] = executer.submit(tasks[r]);
}
executer.shutdown();
executer.awaitTermination(1, TimeUnit.DAYS);
end = System.currentTimeMillis();
for(int r = 0; r< rows; r++){
matrix[r] = returned[r].get();
}
System.out.print("Time taken = " + (end - start) + "\n");
return printArr(matrix);
}
public static String printArr(Integer[][] arr){
String out = "";
for(int i = 0; i < arr.length;i++){
for(int c = 0; c < arr[i].length;c++){
out += arr[i][c].intValue();
}
out += "\n";
}
return out;
} }
類分揀機實現可贖回{ 私人最終整數[]數組;
Sorter(Integer[] array){
this.array = array.clone();
}
@Override
public Integer[] call() throws Exception {
boolean swap = true;
int buffer = 0;
while(swap){
swap = false;
for(int i = 0; i < array.length -1; i++){
if(array[i].intValue() > array[i+1].intValue()){
buffer = array[i].intValue();
array[i]= array[i+1].intValue();
array[i+1] = buffer;
swap = true;
}
}
}
return array;
}
}