为什么在ide中运行.jar要比运行相同的.java文件花费2-3倍的时间？

复活节期间，我制作了一个程序，它将获取一个大的日志文件，读入并解析它，然后用javafx将其输出到一个表视图。该程序工作正常，因此使用Intellij将其制作成一个.jar，这样就可以在没有IDE的情况下轻松使用

然而，当以JAR形式运行I/O方法时，运行程序所需的时间大约是运行程序的2-3倍

（.java文件）3.5秒读入->（.jar文件）11.3秒

（.java文件）0.014秒写入->（.jar文件）0.034秒

/**
 * Method that filters a file based on a search string and a selected radio button
 *
 * @param num          index of a selected radio button
 * @param filterSearch String that is being searched for
 * @param path         Of the log file that is being filtered through
 * @return The new file that contains only the desired lines
 */
public static String filterFile(int num, String filterSearch, String path) {

    long startTime = System.currentTimeMillis();


    ArrayList<String> toOutput = new ArrayList<>();

    BufferedReader  reader = null;

    File inputFile = new File(path);
    try {

        reader = new BufferedReader(new FileReader(inputFile));
        String searchString = null;

        //While the log file has a line
        //the next line to be searched is stored in searchString
        while ((searchString = reader.readLine())!=null) {

            switch (num) {
                //if the user radio button is selected
                case 1:
                    //if the searchString contains the filter search
                    //print the whole line to the new file
                    if (searchString.contains("user=\"" + filterSearch)) {
                      toOutput.add(searchString);
                    }
                    break;
                case 2:
                    //if the searchString contains the filter search
                    //print the whole line to the new file
                    if (searchString.contains("srcip=\"" + filterSearch)) {
                        toOutput.add(searchString);
                    }
                    break;
            }

        }

    } catch (IOException e) {
        System.out.println("Cannot open file: ");
        System.exit(0);
    }finally {

        try{
            reader.close();

        }catch (IOException ef){

        }

    }
    long endTime = System.currentTimeMillis();
    double duration = (endTime - startTime)/1000.0;


    System.out.println("first formatedSeconds = "+ duration);
    return createFilterFile(toOutput);
}

我已经阅读了有关这方面的老问题。我已经尝试过对这些方法进行计时，确保使用最新的JDK/JRE

我敢肯定，作为jar运行时，这些方法的速度会减慢：

/**
 * Method that filters a file based on a search string and a selected radio button
 *
 * @param num          index of a selected radio button
 * @param filterSearch String that is being searched for
 * @param path         Of the log file that is being filtered through
 * @return The new file that contains only the desired lines
 */
public static String filterFile(int num, String filterSearch, String path) {

    long startTime = System.currentTimeMillis();


    ArrayList<String> toOutput = new ArrayList<>();

    Scanner in = null;

    File inputFile = new File(path);
    try {
        in = new Scanner(inputFile);

        String searchString = null;

        //While the log file has a line
        while (in.hasNext()) {
            //the next line to be searched is stored in searchString
            searchString = in.nextLine();

            switch (num) {
                //if the user radio button is selected
                case 1:
                    //if the searchString contains the filter search
                    //print the whole line to the new file
                    if (searchString.contains("user=\"" + filterSearch)) {
                        //System.out.println(searchString);
                      toOutput.add(searchString);
                    }
                    break;
                case 2:
                    //if the searchString contains the filter search
                    //print the whole line to the new file
                    if (searchString.contains("srcip=\"" + filterSearch)) {
                        toOutput.add(searchString);
                    }
                    break;
            }

        }


    } catch (Exception e) {
        System.out.println("Cannot open file: ");
        System.exit(0);
    }finally {
        in.close();
    }
    long endTime = System.currentTimeMillis();
    double duration = (endTime - startTime)/1000.0;


    System.out.println("first formatedSeconds = "+ duration);
    return createFilterFile(toOutput);
}

/**
 *  Create a new file with the filtered results inside
 * @param toPrint lines from the log file that have been filtered out
 * @return Path to this new file
 */
private static String createFilterFile(ArrayList<String> toPrint){
    long startTime = System.currentTimeMillis();

    Date date = new Date();
    String fileName = "New filtered search file " + sdf.format(date) + ".log";
    PrintWriter out = null;
    try{
        FileWriter outputFile = new FileWriter(fileName, true);


        out = new PrintWriter(outputFile);

        for(String item: toPrint){
            out.println(item);
        }


    }catch(Exception e){
        e.printStackTrace();
    }finally {
        out.close();
    }
    long endTime = System.currentTimeMillis();
    double duration = (endTime - startTime)/1000.0;

    // formatedSeconds = (0.xy seconds)

    System.out.println("second formatedSeconds = "+ duration);

    return fileName;
}

/**
*方法，该方法基于搜索字符串和选定单选按钮筛选文件
*
*@param num所选单选按钮的索引
*@param filterSearch正在搜索的字符串
*正在筛选的日志文件的@param路径
*@返回仅包含所需行的新文件
*/
公共静态字符串筛选器文件（int num、字符串筛选器搜索、字符串路径）{
long startTime=System.currentTimeMillis（）；
ArrayList toOutput=新的ArrayList（）；
扫描仪输入=空；
文件输入文件=新文件（路径）；
试一试{
in=新扫描仪（输入文件）；
字符串searchString=null；
//而日志文件有一行
while（在.hasNext（）中）{
//要搜索的下一行存储在searchString中
searchString=in.nextLine（）；
开关（num）{
//如果选择了用户单选按钮
案例1：
//如果searchString包含筛选器搜索
//将整行打印到新文件中
if（searchString.contains（“用户=\”“+filterSearch））{
//System.out.println（搜索字符串）；
添加（搜索字符串）；
}
打破
案例2：
//如果searchString包含筛选器搜索
//将整行打印到新文件中
if（searchString.contains（“srcip=\”“+filterSearch））{
添加（搜索字符串）；
}
打破
}
}
}捕获（例外e）{
System.out.println（“无法打开文件：”）；
系统出口（0）；
}最后{
in.close（）；
}
long-endTime=System.currentTimeMillis（）；
双持续时间=（结束时间-开始时间）/1000.0；
System.out.println（“第一个格式化的秒数=+持续时间”）；
返回createFilterFile（toOutput）；
}
/**
*创建一个包含筛选结果的新文件
*@param toPrint已从日志文件中筛选出的行
*@返回此新文件的路径
*/
私有静态字符串createFilterFile（ArrayList toPrint）{
long startTime=System.currentTimeMillis（）；
日期=新日期（）；
String fileName=“新筛选的搜索文件”+sdf.format（date）+“.log”；
PrintWriter out=null；
试一试{
FileWriter outputFile=新的FileWriter（文件名，true）；
out=新的PrintWriter（输出文件）；
用于（字符串项：toPrint）{
out.println（项目）；
}
}捕获（例外e）{
e、 printStackTrace（）；
}最后{
out.close（）；
}
long-endTime=System.currentTimeMillis（）；
双持续时间=（结束时间-开始时间）/1000.0；
//FormattedSeconds=（0.xy秒）
System.out.println（“第二个格式化秒数=+持续时间”）；
返回文件名；
}

Edit在这两种方法中都添加了finally子句，没有改变任何性能

这段代码获取大日志文件，在每行中搜索搜索字符串并将其添加到数组列表中，然后创建一个新文件。此文件要小得多，因此可以轻松打开

任何对提高jar性能的帮助都将不胜感激，因为我对.jar文件没有太多经验

编辑：从扫描仪更改为缓冲读卡器大大提高了性能

（.java文件）1.39秒读入->（.jar文件）1.82秒

（.java文件）0.014秒写入->（.jar文件）0.034秒

/**
 * Method that filters a file based on a search string and a selected radio button
 *
 * @param num          index of a selected radio button
 * @param filterSearch String that is being searched for
 * @param path         Of the log file that is being filtered through
 * @return The new file that contains only the desired lines
 */
public static String filterFile(int num, String filterSearch, String path) {

    long startTime = System.currentTimeMillis();


    ArrayList<String> toOutput = new ArrayList<>();

    BufferedReader  reader = null;

    File inputFile = new File(path);
    try {

        reader = new BufferedReader(new FileReader(inputFile));
        String searchString = null;

        //While the log file has a line
        //the next line to be searched is stored in searchString
        while ((searchString = reader.readLine())!=null) {

            switch (num) {
                //if the user radio button is selected
                case 1:
                    //if the searchString contains the filter search
                    //print the whole line to the new file
                    if (searchString.contains("user=\"" + filterSearch)) {
                      toOutput.add(searchString);
                    }
                    break;
                case 2:
                    //if the searchString contains the filter search
                    //print the whole line to the new file
                    if (searchString.contains("srcip=\"" + filterSearch)) {
                        toOutput.add(searchString);
                    }
                    break;
            }

        }

    } catch (IOException e) {
        System.out.println("Cannot open file: ");
        System.exit(0);
    }finally {

        try{
            reader.close();

        }catch (IOException ef){

        }

    }
    long endTime = System.currentTimeMillis();
    double duration = (endTime - startTime)/1000.0;


    System.out.println("first formatedSeconds = "+ duration);
    return createFilterFile(toOutput);
}

/**
*方法，该方法基于搜索字符串和选定单选按钮筛选文件
*
*@param num所选单选按钮的索引
*@param filterSearch正在搜索的字符串
*正在筛选的日志文件的@param路径
*@返回仅包含所需行的新文件
*/
公共静态字符串筛选器文件（int num、字符串筛选器搜索、字符串路径）{
long startTime=System.currentTimeMillis（）；
ArrayList toOutput=新的ArrayList（）；
BufferedReader reader=null；
文件输入文件=新文件（路径）；
试一试{
reader=newbufferedreader（newfilereader（inputFile））；
字符串searchString=null；
//而日志文件有一行
//要搜索的下一行存储在searchString中
而（（searchString=reader.readLine（））！=null）{
开关（num）{
//如果选择了用户单选按钮
案例1：
//如果searchString包含筛选器搜索
//将整行打印到新文件中
if（searchString.contains（“用户=\”“+filterSearch））{
添加（搜索字符串）；
}
打破
案例2：
//如果searchString包含筛选器搜索
//将整行打印到新文件中
if（searchString.contains（“srcip=\”“+filterSearch））{
添加（搜索字符串）；
}