如何用java按行读取大文件

通用做法：

try (BufferedReader br = new BufferedReader(new FileReader(file))) {
    String line;
    while ((line = br.readLine()) != null) {
       // process the line.
    }
}

稍微通用一点做法：

try(BufferedReader br = new BufferedReader(new FileReader(file))) {
    for(String line; (line = br.readLine()) != null; ) {
        // process the line.
    }
    // line is not visible here.
}

在java8 中你可以参考如下方式：

try (Stream stream = Files.lines(Paths.get(fileName))) {
        stream.forEach(System.out::println);
}

指定编码规则方式如下：

try {
    BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(filePath), "Cp1252"));         

    String line;
    while ((line = br.readLine()) != null) {
        // process the line.
    }
    br.close();

} catch (IOException e) {
    e.printStackTrace();
}