在读取文本文件时跳过一定数量的行- BufferedReader Java
在读取文本文件时跳过一定数量的行- BufferedReader Java
提问于 2018-10-05 17:06:54
我在一个目录中有几个文件，我打算跳过一定数量的行。获取要跳过的行的唯一方法是获取字符长度为1的行的第一个匹配项。唯一可用的信息是该行出现在第60行之前的任何位置。因此，我编写了以下方法来尝试跳过字符之前的行。但我最终得到了与原始文件相同的文件：
public static void editSplitFiles(File sourceDir) {
FilenameFilter only = new OnlyExt("RPT");
log.debug("Editing Split Files........");
String[] filenames = sourceDir.list(only);
try {
for (int k = 0; k < filenames.length; k++) {
FileInputStream fs = new FileInputStream(sourceDir.getAbsolutePath() + System.getProperty("file.separator") + filenames[k]);
BufferedReader br = new BufferedReader(new InputStreamReader(fs));
FileOutputStream fos = new FileOutputStream(sourceDir.getAbsolutePath() + System.getProperty("file.separator") + filenames[k] + ".LST");
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(fos));
String strLine;
int num = 0;
int splitLine = 0;
while ((strLine = br.readLine()) != null) {
num++;
if (strLine.length() == 1) {
splitLine = num;
}
bw.write(strLine);
bw.newLine();
bw.flush();
}
if (splitLine < 60) {
log.debug("File Name" + filenames[k] + "Line Number - " + splitLine);//This gives me the correct line number where the character is for each file.
br.readLine();
}
fs.close();
br.close();
fos.close();
bw.close();
}
} catch (Exception asd) {
log.debug(asd.getMessage());
}
}我不确定我做错了什么，但看起来在我跳过之前文件已经被写入了。我该如何做到这一点？
EDIT文件如下所示：
回答 1
Stack Overflow用户
回答已采纳
发布于 2018-10-05 18:50:35
我已经通过在Map中存储要跳过每个文件的值的行来解决这个问题。然后遍历映射并跳过每个文件的行数。我想应该有一个简单的方法来解决它。
public static Map getSplitMap(File sourceDir) {
FilenameFilter only = new OnlyExt("RPT");
log.debug("Getting split Map........");
Map<String, Integer> map = new HashMap();
String[] filenames = sourceDir.list(only);
try {
for (int k = 0; k < filenames.length; k++) {
FileInputStream fs = new FileInputStream(sourceDir.getAbsolutePath() + System.getProperty("file.separator") + filenames[k]);
BufferedReader br = new BufferedReader(new InputStreamReader(fs));
String strLine;
int num = 0;
int splitLine = 0;
while ((strLine = br.readLine()) != null) {
num++;
if (strLine.length() == 1) {
splitLine = num;
}
if (splitLine < 60) {
map.put(filenames[k], splitLine);
}
}
fs.close();
br.close();
}
} catch (Exception asd) {
log.debug(asd.getMessage());
}
return map;
}然后跳过每个文件的行：
public static void splitFile(File sourceDir) {
Map<String, Integer> map = getSplitMap(sourceDir);
try {
for (Map.Entry<String, Integer> entry : map.entrySet()) {
FileInputStream fs = new FileInputStream(sourceDir.getAbsolutePath() + System.getProperty("file.separator") + entry.getKey());
BufferedReader br = new BufferedReader(new InputStreamReader(fs));
FileOutputStream fos = new FileOutputStream(sourceDir.getAbsolutePath() + System.getProperty("file.separator") + entry.getKey() + ".LST");
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(fos));
for (int i = 1; i < entry.getValue(); i++) {
br.readLine();
}
String strLine;
while ((strLine = br.readLine()) != null) {
bw.write(strLine);
bw.newLine();
bw.flush();
}
fs.close();
br.close();
fos.close();
bw.close();
File files = new File(sourceDir.getAbsolutePath() + System.getProperty("file.separator") + entry.getKey());
files.delete();
}
} catch (Exception asd) {
log.debug(asd.getMessage());
}
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/52662061
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