Question

嘿伙计我正在编写一个解析器代码来读取.csv文件并将其解析为XML。这是我的代码，它工作正常，但我希望它跳过文件中的第一行。所以我决定建立一个HashMap，但似乎确实有效：

for (int i = 0; i < listOfFiles.length; i++) {
        File file = listOfFiles[i];
        if (file.isFile() && file.getName().endsWith(".csv")){

            System.out.println("File Found: " + file.getName());//Prints the name of the csv file found

            String filePath = sourcepath + "\\" + file.getName();

            BufferedReader br = new BufferedReader(new FileReader(file));  


String line;
int n = 1;
Map<Integer,String> lineMap = new HashMap<Integer,String>();
int k=2;
while ((line = br.readLine()) != null) {
    System.out.println(n + " iteration(s) of 1st While Loop");

                    lineMap.put(k, line);

    fw.write("          <ASSET action=\"AddChange\">\n");
    fw.write("              <HOSTNAME>\n");
    hostName=line.substring(0, line.indexOf(","));
    fw.append(hostName);
    fw.write("</HOSTNAME>\n");
    fw.write("              <HOSTID>\n");
    hostID=line.substring(line.indexOf(",")+1, nthOccurrence(line, ',', 1));
    fw.append(hostID);
    fw.write("</HOSTID>\n");
    fw.write("              <MACMODEL>\n");
    machineModel=line.substring(nthOccurrence(line, ',', 1)+1, nthOccurrence(line, ',', 2));
    fw.append(machineModel);
    fw.write("</MACMODEL>\n");
    fw.write("              <PROMODEL>\n");
    processorModel=line.substring(nthOccurrence(line, ',', 2)+1, nthOccurrence(line, ',', 3));
    fw.append(processorModel);
    fw.write("</PROMODEL>\n");
    fw.write("              <CORE>\n");
    core=line.substring(nthOccurrence(line, ',', 3)+1, nthOccurrence(line, ',', 4));
    fw.append(core);
    fw.write("</CORE>\n");
    fw.write("              <PROC>\n");
    proc=line.substring(nthOccurrence(line, ',', 4)+1, nthOccurrence(line, ',', 5));
    fw.append(proc);
    fw.write("</PROC>\n");
    fw.write("              <TIER>\n");
    tier=line.substring(nthOccurrence(line, ',', 5)+1, nthOccurrence(line, ',', 6));
    fw.append(tier);
    fw.write("</TIER>\n");
    fw.write("              <PRODNAME>\n");
    productName=line.substring(nthOccurrence(line, ',', 6)+1, nthOccurrence(line, ',', 7));
    fw.append(productName);
    fw.write("</PRODNAME>\n");
    fw.write("              <VERSION>\n");
    version=line.substring(nthOccurrence(line, ',', 7)+1, nthOccurrence(line, ',', 8));
    fw.append(version);
    fw.write("</VERSION>\n");
    fw.write("              <SCRIPTDATA>\n");
    scriptData=line.substring(nthOccurrence(line, ',', 8)+1, line.length());
    fw.append(scriptData);
    fw.write("</SCRIPTDATA>\n");


  fw.write("            </ASSET>\n");
  k++;
}n++;

这是代码主要部分的片段。任何想法或解决方案???

Answer 1

您可以考虑在while循环之前放置headerLine = br.readLine()，以便与文件的其余部分分开使用标头。您也可以考虑使用opencsv进行csv解析，因为它可以简化您的逻辑。

Answer 2

创建变量interation并使用0进行初始化。在while循环中首先检查它。

String line;
int iteration = 0;
while ((line = br.readLine()) != null) {
    if(iteration == 0) {
        iteration++;  
        continue;
    }
    ...
    ...
}

Answer 3

我觉得有必要添加一个java 8风格的答案。

List<String> xmlLines = new BufferedReader(new FileReader(csvFile))
    .lines()
    .skip(1) //Skips the first n lines, in this case 1      
    .map(s -> {
        //csv line parsing and xml logic here
        //...
        return xmlString;
    })
    .collect(Collectors.toList());

Answer 4

为什么不直接使用for循环

for(int i=1; (line = br.readLine()) != null; i++)
{
    //Your code
}

Answer 5

我对你的代码感到困惑，你有了lineMap，你也有fw（无论是什么）。你在用哪一个？你说你想跳过第一行，但你没有

if (firstLine == true) {
   firstLine = false;
   continue;
}

我还建议使用类似CSVReader的库，我相信它甚至有一个属性ignoreFirstLine

http://opencsv.sourceforge.net/apidocs/au/com/bytecode/opencsv/CSVReader.html

Answer 6

使用缓冲读取器两次，如下所示：

while ((line = br.readLine()) != null) {
  while ((line = br.readLine()) != null) {
    //your code                     
  }
}

Answer 7

boolean isRecord = false;
for (CSVRecord record : records) {
    if(isRecord){
        //process records here.
    }else{
        isRecord = true;
    }
}

而不是添加计数器添加标志将不会达到性能。

Answer 8

一种简单的技术，声明一个变量并为其赋值（例如int k = 0;），然后在进入循环后立即增加变量值。代码如下。

BufferedReader csvReader = new BufferedReader(new FileReader("mycsv.csv"));
        // declare a variable
        int k=0;
        while ((row = csvReader.readLine()) != null) {
            if(k == 0){
                k++;
                continue;
            }
         //rest of your code 
         // inside while loop
        }

Answer 9

对于跳过第一行（通常包含列的标题），取一个变量并在while循环中增加此变量，然后继续;

int lineNumber = 0;

and then in while loop 

while ((line = br.readLine()) != null) {
                        if(lineNumber == 0) {
                            lineNumber++;
                            continue;
                        }
                        lineNumber++;

                       //do waterver u have to do with the tokens in this line(second line)

            }

在Java中读取CSV文件时跳过第一行

9 个答案: