Question

我有一个使用方法管理所有设置的类：

public class SettingsManager {

    public String settingsFileName = Start.programName + ".settings";

    public SettingsManager(String settingsFileName) {
        this.settingsFileName = settingsFileName;
    }

    public void saveIntoNewSettings(String nameOfSetting, String settingValue) {
        Properties programProperties = new Properties();
        OutputStream outputStream = null;
        try {
            outputStream = new FileOutputStream(this.settingsFileName);
            programProperties.setProperty(nameOfSetting, settingValue);
            programProperties.store(outputStream, null);
            outputStream.close();
        }
        catch (Exception errorException) {
            Common.errorEncountered(errorException, "An error occured while trying to save a setting into the file " + this.settingsFileName + ".");
        }
    }

    public void saveSetting(String nameOfSetting, String settingValue) {
        try {
            InputStream inputStream = new FileInputStream(this.settingsFileName);
            OutputStream outputStream = new FileOutputStream(this.settingsFileName);
            Properties programProperties = new Properties();
            programProperties.load(inputStream);
            inputStream.close();
            programProperties.setProperty(nameOfSetting, settingValue);
            programProperties.store(outputStream, null);
            outputStream.close();
        }
        catch (Exception errorException) {
            Common.errorEncountered(errorException, "An error occured while trying to load a setting from the file " + this.settingsFileName + ".");
        }
    }

    public String loadSetting(String nameOfSetting) {
        Properties programProperties = new Properties();
        InputStream inputStream = null;
        try {
            inputStream = new FileInputStream(this.settingsFileName);
            programProperties.load(inputStream);
            inputStream.close();
            return programProperties.getProperty(nameOfSetting);
        }
        catch (Exception errorException) {
            Common.errorEncountered(errorException, "An error occured while trying to load a setting from the file " + this.settingsFileName + ".");
        }
        return "";
    }

    public boolean settingsFileExists() {
        File settingsFile = new File(settingsFileName);
        if (settingsFile.exists() && !settingsFile.isDirectory()) {
            return true;
        }
        else {
            return false;
        }
    }
}

在创建名为＆＃34; mainSettings＆＃34;的这个类的实例后，我在我的主类中运行这两行代码：

mainSettings.saveSetting("hello1", "world1");
mainSettings.saveSetting("hello2", "world2");

在我的设置文件中，我看到的只有：

hello2=world2

出于某种原因，每次调用saveSetting方法时，它都会删除设置文件中的旧值。当我打电话给＃34; programProperties.load(inputStream);＆＃34;。

时，我认为应该保存这些值

Answer 1

创建OutputStream时，文件被截断为0字节。感染您没有阅读任何属性。试试这个：

public void saveSetting(String nameOfSetting, String settingValue) {
    try {
        InputStream inputStream = new FileInputStream(this.settingsFileName);
        Properties programProperties = new Properties();
        programProperties.load(inputStream);
        inputStream.close();
        OutputStream outputStream = new FileOutputStream(this.settingsFileName);
        programProperties.setProperty(nameOfSetting, settingValue);
        programProperties.store(outputStream, null);
        outputStream.close();
    }
    catch (Exception errorException) {
        Common.errorEncountered(errorException, "An error occured while trying to load a setting from the file " + this.settingsFileName + ".");
    }
}

应解决您的问题。

Java - 在属性文件中设置值将覆盖以前的值

1 个答案: