我已经用下面这个成语有一段时间了。这似乎是传播最广的,至少在我访问过的网站上。
在Java中有没有更好/不同的方法将文件读入字符串?
private String readFile(String file) throws IOException {
BufferedReader reader = new BufferedReader(new FileReader (file));
String line = null;
StringBuilder stringBuilder = new StringBuilder();
String ls = System.getProperty("line.separator");
try {
while((line = reader.readLine()) != null) {
stringBuilder.append(line);
stringBuilder.append(ls);
}
return stringBuilder.toString();
} finally {
reader.close();
}
}
如果您无权访问Files类,则可以使用本机解决方案。
static String readFile(File file, String charset)
throws IOException
{
FileInputStream fileInputStream = new FileInputStream(file);
byte[] buffer = new byte[fileInputStream.available()];
int length = fileInputStream.read(buffer);
fileInputStream.close();
return new String(buffer, 0, length, charset);
}
如果您需要字符串处理(并行处理),Java8有很棒的StreamAPI。
String result = Files.lines(Paths.get("file.txt"))
.parallel() // for parallel processing
.map(String::trim) // to change line
.filter(line -> line.length() > 2) // to filter some lines by a predicate
.collect(Collectors.joining()); // to join lines
JDK示例samples/lambda/BulkDataOperations中提供了更多示例,可以从Oracle Java SE 8下载页面下载
另一个单线示例
String out = String.join("\n", Files.readAllLines(Paths.get("file.txt")));