使用BufferedReader读取本地文件的操作
时间：2022-08-24 09:39:58 | 栏目：JAVA代码 | 点击：次
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();
}
}
8. 运行结果：
9. 打开： basic.out文件：
