我正在练习如何使用数组实现队列。我已经轻松实现了如何将队列中的元素入队和出列。但是我在使用堆栈实现队列反向时遇到了异常
lib/ext错误日志是 -
java.lang.IllegalStateException: Invalid use of BasicClientConnManager: connection still allocated.
Make sure to release the connection before allocating another one.
at org.apache.http.util.Asserts.check(Asserts.java:34)
at org.apache.http.impl.conn.BasicClientConnectionManager.getConnection(BasicClientConnectionManager.java:166)
at org.apache.http.impl.conn.BasicClientConnectionManager$1.getConnection(BasicClientConnectionManager.java:148)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:424)
at org.apache.http.impl.client.AbstractHttpClient.doExecute(AbstractHttpClient.java:884)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:82)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:107)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:55)
at org.jmeterplugins.repository.PluginManager.getJSON(PluginManager.java:137)
at org.jmeterplugins.repository.PluginManager.load(PluginManager.java:78)
at org.jmeterplugins.repository.PluginManagerDialog.componentShown(PluginManagerDialog.java:178)
at java.awt.Component.processComponentEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Window.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.WaitDispatchSupport$2.run(Unknown Source)
at java.awt.WaitDispatchSupport$4.run(Unknown Source)
at java.awt.WaitDispatchSupport$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.awt.WaitDispatchSupport.enter(Unknown Source)
at java.awt.Dialog.show(Unknown Source)
at java.awt.Component.show(Unknown Source)
at java.awt.Component.setVisible(Unknown Source)
at java.awt.Window.setVisible(Unknown Source)
at java.awt.Dialog.setVisible(Unknown Source)
at org.jmeterplugins.repository.PluginManagerMenuItem.actionPerformed(PluginManagerMenuItem.java:41)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.AbstractButton.doClick(Unknown Source)
at javax.swing.plaf.basic.BasicMenuItemUI.doClick(Unknown Source)
at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
答案 0 :(得分：0)
您的出列方法存在问题： 1.你在前面= 0并试图访问前-1，即-1 结果引发了异常。
更正了工作代码。
public class QueueImpl {
private int capacity;
int queueArr[];
int front = 0;
int rear = -1;
int currentSize = 0;
QueueImpl(int queueSize) {
this.capacity = queueSize;
queueArr = new int[this.capacity];
}
public void enqueue(int data) {
if (isQueueFull()) {
System.out.println("Overflow");
return;
} else {
rear = rear + 1;
if (rear == capacity - 1) {
rear = 0;
}
queueArr[rear] = data;
currentSize++;
System.out.println("Element " + data + " is pushed to Queue !");
}
}
public int dequeue() {
int element=-1;
if (isQueueEmpty()) {
System.out.println("UnderFlow");
} else {
element = queueArr[front];
front=front+1;
if (front == capacity - 1) {
System.out.println("Pop operation done ! removed: "
+ queueArr[front - 1]);
front = 0;
} else {
System.out.println("Pop operation done ! removed: "
+ queueArr[front - 1]);
}
currentSize--;
}
return element;
}
private boolean isQueueEmpty() {
boolean status = false;
if (currentSize == 0) {
status = true;
}
return status;
}
private boolean isQueueFull() {
boolean status = false;
if (currentSize == capacity) {
status = true;
}
return status;
}
public static void main(String arg[]) {
QueueImpl queueImpl = new QueueImpl(5);
queueImpl.enqueue(5);
queueImpl.enqueue(2);
queueImpl.enqueue(9);
queueImpl.enqueue(1);
queueImpl.printQueue(queueImpl);
queueImpl.reverse(queueImpl);
queueImpl.printQueue(queueImpl);
}
private void printQueue(QueueImpl queueImpl) {
System.out.println(queueImpl.toString());
}
@Override
public String toString() {
return "Queue [front=" + front + ", rear=" + rear + ", size="
+ currentSize + ", queue=" + Arrays.toString(queueArr) + "]";
}
private QueueImpl reverse(QueueImpl queueImpl)
throws ArrayIndexOutOfBoundsException {
Stack<Integer> stack = new Stack<Integer>();
while (!queueImpl.isQueueEmpty()) {
stack.push(queueImpl.dequeue());
}
while (!stack.isEmpty()) {
queueImpl.enqueue(stack.pop());
}
return queueImpl;
}
}