使用BufferedReader读取本地文件的操作

这篇文章主要介绍了使用BufferedReader读取本地文件的操作，具有很好的参考价值，希望对大家有所帮助。

BufferedReader读取本地文件

在使用BufferedWriter写入文件时，如果忘记关闭文件（close）同时也没有调用flush(),则被写入的文件中是没有内容的。

在关闭 文件的同时系统会自动 调用flush()

try { File file=new File("c://aa.txt"); FileInputStream is=new FileInputStream(file); InputStreamReader reader=new InputStreamReader(is,"GBK"); BufferedReader br=new BufferedReader(reader); String line=null; while ((line=br.readLine())!=null) { System.out.println(line); } reader.close(); br.close(); is.close(); } catch (Exception e) { // Todo Auto-generated catch block e.printstacktrace(); } }

BufferedReader 读取文件 内容，原样输出

1.新建目标类：

package com.xuzhiwen.io; public class TargetFile { public static void main(String[] args) { System.out.println("TargetFile.java"); } }

2.测试类：

package com.xuzhiwen.io; import java.io.BufferedReader; import java.io.FileReader; public class TestBufferedReader { public static void main(String[] args) throws Exception { String filepath = "src/com/xuzhiwen/io/TargetFile.java"; BufferedReader read = new BufferedReader(new FileReader(filepath)); String s; StringBuffer sb = new StringBuffer(); while((s=read.readLine()) != null){ sb.append(s+"n"); } read.close(); System.out.println(sb); } }

3.输出结果为：

4.文件结构树：

5. 将结果用StringReader再读一次：

package com.xuzhiwen.io; import java.io.BufferedReader; import java.io.FileReader; import java.io.StringReader; public class TestBufferedReader { public static void main(String[] args) throws Exception { String filepath = "src/com/xuzhiwen/io/TargetFile.java"; BufferedReader read = new BufferedReader(new FileReader(filepath)); String s; StringBuffer sb = new StringBuffer(); while((s=read.readLine()) != null){ sb.append(s+"n"); } read.close(); System.out.println(sb); StringReader sr = new StringReader(sb.toString()); int c; while((c=sr.read()) != -1){ System.out.print((char)c); } } }

6. 运行结果如下:

7. 将内容写入文件：

package com.xuzhiwen.io; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.FileReader; import java.io.FileWriter; import java.io.PrintWriter; import java.io.StringReader; public class TestBufferedReader { public static void main(String[] args) throws Exception { String filepath = "src/com/xuzhiwen/io/TargetFile.java"; BufferedReader read = new BufferedReader(new FileReader(filepath)); String s; StringBuffer sb = new StringBuffer(); while((s=read.readLine()) != null){ sb.append(s+"n"); } read.close(); System.out.println(sb); System.out.println("=============================================="); StringReader sr = new StringReader(sb.toString()); int c; while((c=sr.read()) != -1){ System.out.print((char)c); } sr.close(); System.out.println("=============================================="); String file = "basic.out"; BufferedReader br = new BufferedReader(new StringReader(sb.toString())); PrintWriter pw = new PrintWriter(new BufferedWriter(new FileWriter(file))); int lineCount = 1; String ss; while((ss=br.readLine()) != null){ pw.println(lineCount+": "+ss); lineCount++; } pw.close(); } }