我正在以下面的方式读取文件的每一行
BufferedReader in = new BufferedReader(new FileReader(inFile));
while (null != (line = in.readLine())) {
}
我想单独在第一行和最后一行做一些验证。有没有 检查它是否是 while 循环中的第一行和最后一行的方法
while (null != (line = in.readLine())) {
if(firstlineoffile) {
}
else if (lastlineoffile) {
}
else
{
}
}
最佳答案
很酷的问题。我玩了一下，这是一个 SSCCE , 只需复制'n'粘贴'然后'运行它。
package com.stackoverflow.q2292917;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;
public class Test {
public static void main(String... args) throws IOException {
// Create test file.
File file = new File("/test.txt");
PrintWriter writer = new PrintWriter(file);
writer.println("line 1");
writer.println("line 2");
writer.println("line 3");
writer.println("line 4");
writer.println("line 5");
writer.close();
// Read test file.
BufferedReader reader = null;
try {
reader = new BufferedReader(new FileReader(file));
String next, line = reader.readLine();
for (boolean first = true, last = (line == null); !last; first = false, line = next) {
last = ((next = reader.readLine()) == null);
if (first) {
System.out.println("first line: " + line);
} else if (last) {
System.out.println("last line: " + line);
} else {
System.out.println("normal line: " + line);
}
}
} finally {
if (reader != null) try { reader.close(); } catch (IOException logOrIgnore) {}
}
// Delete test file.
file.delete();
}
}
输出:
first line: line 1 normal line: line 2 normal line: line 3 normal line: line 4 last line: line 5
然而，我质疑初学者的可读性和可解释性...... ;)
关于java - 如何在 reader.readLine() 期间检测第一行和最后一行？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/2292917/