从.text中挑选特定数据并在csv中写为列

Question

这是.txt的一部分：

Thu Mar 28 12:18:28 EDT 2013

MemFree：601836 kB

Linux 2.6.18-308.el5（CWAPP1.conceptwave.com）03/28/2013

avg-cpu：％user％nice％system％iowait％steal％idle            0.15 0.00 0.05 0.02 0.00 99.79

========================

Thu Mar 28 12:18:38 EDT 2013

MemFree：598312 kB

Linux 2.6.18-308.el5（CWAPP1.conceptwave.com）03/28/2013

avg-cpu：％user％nice％system％iowait％steal％idle            0.15 0.00 0.05 0.02 0.00 99.79

========================

我需要读取日期，内存空闲和％空闲，并写入两个包含两列的csv文件。一个是日期和内存，另一个是日期和％空闲。所以我编写了读取数据的代码并将其附加到3个列表中。如何将它们写入2个csv文件，以满足我的要求？

提前致谢。

我的代码：

List<String> dateTime = new ArrayList<String>();
List<String> memFree = new ArrayList<String>(); 
List<String> pIdle = new ArrayList<String>();

public static void main(String[] args) 
{
    // TODO Auto-generated method stub

}

public void readFile(String file)
{

    try
    {
        BufferedReader br = new BufferedReader(new FileReader(file));
        String str = null; 

        try 
        {
            while((str=br.readLine()) != null)
            {
                String[] st = str.split("\\s+");  

                if (st[0] == "MemFree:")
                    memFree.add(st[1]); 

                if(isDouble(st))
                    pIdle.add(st[4]);                   

                if(isDate(str))
                {
                    String subStr = str.substring(0, 15);
                    dateTime.add(subStr); 
                }


            }
        }

        finally
        {
            br.close(); 
        }
    }

    catch(FileNotFoundException e)
    {
        System.out.println("File not found!");
    }

    catch(IOException e)
    {
        System.out.println(e);
    }

}

public boolean isDate(String str)
{
    DateFormat df = new SimpleDateFormat("E M d");

    try
    {
        String subStr = str.substring(0, 8);
        @SuppressWarnings("unused")
        Date currentDate = df.parse(subStr); 
        return true; 
    }

    catch(ParseException e)
    {
        return false; 
    }
}

public boolean isDouble(String[] st)
{

    try
    {
        for (int i = 0; i < st.length;)
        {
            @SuppressWarnings("unused")
            double num = Double.parseDouble(st[i]); 
            return true;
        }

    }

    catch(IllegalArgumentException ex)
    {
        return false; 
    }

    return false;
}

public void writeToCSV(List<String> dateTime, List<String> memFree, List<String> pIdle)
{
    //UNFINISHED - NEED HELP!
    String dateSepVal = "";

    if(dateTime != null && memFree != null)
    {
        Iterator<String> iter = dateTime.iterator(); 

        while(iter.hasNext())
        {
            dateSepVal += iter.next() + ","; 
        }

        if(dateSepVal.endsWith(","))
        {
            dateSepVal = dateSepVal.substring(0, dateSepVal.lastIndexOf(","));
        }
    }

    if(dateTime != null && pIdle !=null)
    {
        //TODO
    }

}

Answer 1

写入文件就像阅读一样，反过来说：

try (BufferedWriter writer = new BufferedWriter(new FileWriter("delete.me"))) {
    writer.write("something");
    writer.newLine();
}

如果您想为每个提取的日期添加一个新行＆amp;内存值，它可能看起来像这样：

public void writeToCSV(List<String> dateTime, List<String> memFree) throws IOException {
    try (BufferedWriter writer = new BufferedWriter(new FileWriter("delete.me"))) {
        if(dateTime == null || memFree == null)
            return;

        Iterator<String> memFrees = memFree.iterator(); 
        for (String dt: dateTimes) {
            if (!memFrees.hasNext())
                return;
            writer.write(dt + "," + memFrees.next());
            writer.newLine();
        }
    }
}

但正如 M Sach 建议的那样，您可能希望看一下这样的框架。