我正在学习C++ interface Java的Swing。我这个程序是接收用户输入的数字来输出相应数量的随机数，然后计算这些随机数的平均数和标准差。当我点击Go后出现了以下报错，请问怎么解决？

报错：

Exception in thread "AWT-EventQueue-0" java.lang.UnsatisfiedLinkError: HelloJNI.HelloJNI.calculateMean([I)D
   at HelloJNI.HelloJNI.calculateMean(Native Method)
   at HelloJNI.HelloJNI.lambda$0(HelloJNI.java:35)
   at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
   at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
   at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
   at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
   at javax.swing.plaf.basic.BasicButtonListener.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)

Java代码：

import javax.swing.*;
import java.awt.*;
import java.util.Random;

public class HelloJNI {
private static JTextField mean; // Save as HelloJNI.java
private static JTextField std;

static {
System.loadLibrary("hello"); // Load native library hello.dll (Windows) or libhello.so (Unixes)
// at runtime
// This library contains a native method called sayHello()
}

// Test Driver
public static void main(String[] args) {
HelloJNI obj = new HelloJNI(); // Create an instance and invoke the native method

JFrame.setDefaultLookAndFeelDecorated(true);
JFrame frame = new JFrame("Layout");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

// Define new buttons
JLabel jl = new JLabel("Enter the number of samples to generate:");
jl.setAlignmentX(Component.CENTER_ALIGNMENT);
JTextField textField = new JTextField("TextBox");
textField.setMaximumSize(textField.getPreferredSize());
JButton jb1 = new JButton("Go");
jb1.addActionListener(e -> {
int n = Integer.parseInt(textField.getText());
if (n > 0) {
int[] arr = generateArray(n);
update(obj.calculateMean(arr), obj.calculateSTDDev(arr));
}
});
jb1.setAlignmentX(Component.CENTER_ALIGNMENT);
System.out.println();
JLabel mean_label = new JLabel("Mean =");
mean = new JTextField("TextBox");
mean.setSize(mean.getPreferredSize());
JPanel mean_panel = new JPanel();
mean_panel.setLayout(new FlowLayout());
mean_panel.add(mean_label);
mean_panel.add(mean);
mean_panel.setAlignmentX(Component.CENTER_ALIGNMENT);

JLabel std_label = new JLabel("Standard deviation =");
std = new JTextField("TextBox");
std.setSize(std.getPreferredSize());
JPanel std_panel = new JPanel();
std_panel.setLayout(new FlowLayout());
std_panel.add(std_label);
std_panel.add(std);
std_panel.setAlignmentX(Component.CENTER_ALIGNMENT);

// Define the panel to hold the buttons
JPanel panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
panel.add(jl);
panel.add(textField);
panel.add(jb1);
panel.add(mean_panel);
panel.add(std_panel);

// Set the window to be visible as the default to be false
frame.add(panel);
frame.pack();
frame.setVisible(true);
}

private static void update(double calculateMean, double calculateSTDDev) {
mean.setText(String.format("%.3f", calculateMean));
std.setText(String.format("%.3f", calculateSTDDev));
}

private static int[] generateArray(int n) {
int[] arr = new int[n];
Random r = new Random();
for (int i = 0; i < n; i++) {
arr[i] = r.nextInt(100);
}
return arr;
}

public native double calculateSTDDev(int[] numbers);

public native double calculateMean(int[] numbers);
}

Week8.cpp file:

#include "Week8.h"

#include <jni.h>
#include <iostream>
#include <math.h>
#include "Week8.h"
using namespace std;

JNIEXPORT jdouble JNICALL Java_ClinkGUI_calculateSTDDev(JNIEnv* env, jobject thisObj, jintArray inJNIArray) {
jdouble mean = Java_ClinkGUI_calculateMean(env, thisObj, inJNIArray);
jint* inCArray = env->GetIntArrayElements(inJNIArray, NULL);
if (NULL == inCArray) return 0;
jsize length = env->GetArrayLength(inJNIArray);
jdouble var = 0.0;
for (int i = 0; i < length; ++i)
var += pow((double)inCArray[i] - mean, 2);
env->ReleaseIntArrayElements(inJNIArray, inCArray, 0); // release resources
jdouble std = sqrt(var / length);
return std;
}

JNIEXPORT jdouble JNICALL Java_ClinkGUI_calculateMean(JNIEnv* env, jobject thisObj, jintArray inJNIArray) {
jint* inCArray = env->GetIntArrayElements(inJNIArray, NULL);
if (NULL == inCArray) return 0;
jsize length = env->GetArrayLength(inJNIArray);
// Step 2: Perform its intended operations
jint sum = 0;
int i;
for (i = 0; i < length; i++) {
sum += inCArray[i];
}
jdouble average = (jdouble)sum / length;
env->ReleaseIntArrayElements(inJNIArray, inCArray, 0); // release resources

return average;
}

Week8.h file:

#include <iostream>
#include <jni.h>

#ifndef _Included_ClinkGUI
#define _Included_ClinkGUI
#ifdef __cplusplus
extern "C" {
#endif

   JNIEXPORT jdouble JNICALL Java_ClinkGUI_calculateSTDDev
   (JNIEnv*, jobject, jintArray);

   JNIEXPORT jdouble JNICALL Java_ClinkGUI_calculateMean
   (JNIEnv*, jobject, jintArray);

#ifdef __cplusplus
}
#endif
#endif

使用Spring上传，实现上传进度条

aaron7524

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