ini4j 的单例模式

Question

原问题：程序正在读取旧配置文件 (.ini) 的输入

新问题：尝试使用 stream/ini 的单例模式后，我无法再写入文件。它抛出 java.io.FileNotFoundException.

我是否可以修改我的配置 class 使其正常工作？

提前致谢。

配置class：

import org.ini4j.Wini;
import java.io.*;

//http://www.javenue.info/post/40

public class Configuration {
    private static Configuration _instance = null;

    private Wini ini = null;
    FileInputStream stream;

    private Configuration() {
        ini= new Wini();
        try {
            stream = new FileInputStream(Constants.PATH);
            ini.load(stream);
        }
        catch (Exception e) {
            System.out.println("FILE NOT FOUND!");
        }
    }

    public synchronized static Configuration getInstance() {
        if (_instance == null)
            _instance = new Configuration();
        return _instance;
    }

    public String getConfig(String xSectionName, String xFieldValue){

        String readValue = null;

        if (ini.get(xSectionName, xFieldValue) != null) {
            readValue = ini.get(xSectionName, xFieldValue);
        } else {
            // TODO: What should happen
        }
        return readValue;
    }

    public void setConfig(String xSectionName, String xFieldValue, String xValue){

        System.out.println("Section: " + xSectionName);
        System.out.println("Field:   " + xFieldValue);
        System.out.println("Value:   " + xValue + "\n\n");

        try {
            ini.put(xSectionName, xFieldValue, xValue);
            ini.store();
        } catch (Exception e1) {
            System.out.println(xValue + " could not be stored.");
            e1.printStackTrace();
        }
    }
}

Section: drift

Field: mu

Value: 5

5 could not be stored.

java.io.FileNotFoundException at org.ini4j.Ini.store(Ini.java:126) at application.prototypes.Configuration.setConfig(Configuration.java:72) at application.prototypes.UserInputs.lambda[=12=](UserInputs.java:92) at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86) at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238) at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191) at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59) at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58) at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56) at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56) at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114) at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74) at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54) at javafx.event.Event.fireEvent(Event.java:198) at javafx.scene.Scene$KeyHandler.process(Scene.java:3964) at javafx.scene.Scene$KeyHandler.access00(Scene.java:3910) at javafx.scene.Scene.impl_processKeyEvent(Scene.java:2040) at javafx.scene.Scene$ScenePeerListener.keyEvent(Scene.java:2501) at com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:216) at com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:148) at java.security.AccessController.doPrivileged(Native Method) at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleKeyEvent3(GlassViewEventHandler.java:247) at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389) at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleKeyEvent(GlassViewEventHandler.java:246) at com.sun.glass.ui.View.handleKeyEvent(View.java:546) at com.sun.glass.ui.View.notifyKey(View.java:966) at com.sun.glass.ui.win.WinApplication._runLoop(Native Method) at com.sun.glass.ui.win.WinApplication.lambda$null8(WinApplication.java:191) at java.lang.Thread.run(Unknown Source)

新问题的解决方案：请参阅下面的答案。

原始问题的解决方案：

我正在使用 Java-Runtime-Compiler 库动态加载 class。经过一些研究，我读到一个 ClassLoader 只能有一个特定 class 的实例。因此，解决方案是在 .loadFromJava() 方法中创建一个 ClassLoader 的新实例，然后 boom 问题就解决了。

这是一些代码。

import net.openhft.compiler.CompilerUtils;

...

ClassLoader classloader = new ClassLoader() {
        };

Class aClass = CompilerUtils.CACHED_COMPILER.loadFromJava(classloader, className, javaCode);

Callable<Object[]> caller = (Callable<Object[]>) aClass.newInstance();

Object[] obj = (Object[]) caller.call();

...

动态 class 实现 Callable 和 returns 对象 - 因此可以检索它在其中创建的任何内容。

Answer 1

我刚刚查看了源代码。
问题是Wini中的void load(InputStream input) class如果要使用相同的Wini实例调用store()方法应该避免加载ini文件.
为什么？因为 store() 方法期望在当前 Wini 的实例中有一个现有的文件字段，但是它找不到它，因为您从流而不是文件加载了 ini。

所以你应该使用 Wini 构造函数加载 ini 文件。构造函数以 a File 作为参数，它还额外设置实例中的字段以加载 ini 内容。

看看这个：

public Wini(File input) throws IOException, InvalidFileFormatException{
        this();
        setFile(input);
        load();
}

所以替换：

 private Configuration() {
        ini = new Wini();
        try {
            stream = new FileInputStream(Constants.PATH);
            ini.load(stream);
        }
        catch (Exception e) {
            System.out.println("FILE NOT FOUND!");
        }
    }

通过这个 :

private Configuration()  {
    try {
        ini= new Wini(new File(Constants.PATH));
    }
    catch (Exception e) {
        LOGGER.error("Exception during init of Configuration",e);
    }
}

这是完整的 class 使用日志记录来记录异常，它使用惰性单例实现而不使用任何显式同步 synchronized:

public class Configuration {

    private static Logger LOGGER = Logger.getLogger(Configuration.class)//

    private static class HolderLazySingleton {
        private static Configuration instance = new Configuration();
    }

    private Wini ini = null;

    private Configuration() {    
        try {
            ini = new Wini(new File(Constants.PATH));    
        } catch (Exception e) {
            LOGGER.error("Exception during init of Configuration",e);
        }
    }

    public static Configuration getInstance() {
        return HolderLazySingleton.instance;
    }

    public String getConfig(String xSectionName, String xFieldValue) {

        String readValue = null;

        if (ini.get(xSectionName, xFieldValue) != null) {
            readValue = ini.get(xSectionName, xFieldValue);
        } else {
            // TODO: What should happen
        }
        return readValue;
    }

    public void setConfig(String xSectionName, String xFieldValue, String xValue) {

        System.out.println("Section: " + xSectionName);
        System.out.println("Field:   " + xFieldValue);
        System.out.println("Value:   " + xValue + "\n\n");

        try {
            ini.put(xSectionName, xFieldValue, xValue);
            ini.store();
        } catch (Exception e1) {
            LOGGER.error(xValue + " could not be stored.", e1);         
        }
    }
}

ini4j 的单例模式

Singleton pattern with ini4j

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fileinputstream