java讀取整個文件輸出字符串的三種方式

直接上代碼：

File file = new File("file_path");

//method 1
String str = FileUtils.readFileToString(file);
System.out.println(str);

//method 2
FileReader fileReader = new FileReader(file);
BufferedReader reader = new BufferedReader(fileReader);
StringBuilder sb = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
    sb.append(line + '\n');
}
reader.close();
System.out.println(sb.toString());

//method 3
FileInputStream io = new FileInputStream(file);
ByteArrayOutputStream os = new ByteArrayOutputStream();
byte[] buf = new byte[10240];
int len;
while ((len = io.read(buf)) > 0) {
    os.write(buf, 0, len);
}
io.close();
System.out.println(os.toString());