java - java读取文件时如何转义以特殊字符开头的行

Question

假设一个文件包含以下几行:

#Do
#not
#use
#these
#lines.

Use
these.

我的目标是只读取那些不以#开头的行。如何在 Java 中以最佳方式完成此操作？

Answer 1

假设您想要累积行(当然您可以对每一行执行所有操作)。

String filePath = "somePath\\lines.txt";

// Lines accumulator.
ArrayList<String> filteredLines = new ArrayList<String>();

BufferedReader bufferedReader = null;
try {
    bufferedReader = new BufferedReader(new FileReader(filePath));
    String line;

    while ((line = bufferedReader.readLine()) != null) {
        // Line filtering. Please note that empty lines
        // will match this criteria!
        if (!line.startsWith("#")) {
            filteredLines.add(line);
        }
    }
}
finally {
    if (bufferedReader != null)
        bufferedReader.close();
}

使用 Java 7 try-with-resources 语句:

String filePath = "somePath\\lines.txt";
ArrayList<String> filteredLines = new ArrayList<String>();

try (Reader reader = new FileReader(filePath);
    BufferedReader bufferedReader = new BufferedReader(reader)) {

    String line;
    while ((line = bufferedReader.readLine()) != null) {
        if (!line.startsWith("#"))
            filteredLines.add(line);
    }
}