package com.file;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
public class TextReadFile {
/*
* 一字节为单位读取
*/
public static void readFileByBytes(String fileName){
File file = new File(fileName); //创建文件
InputStream in = null;
System.out.println("!.以字节为单位读取文件内容：一次读取一个");
try {
in = new FileInputStream(file);
int tempbyte;
while((tempbyte = in.read())!=-1){
System.out.write(tempbyte);
}
in.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return;
}
System.out.println("2.以字节为单位读取文件内容：一次读取多个字节：");
try {
byte[] temptypes = new byte[1024];
int byteread = 0;
in = new FileInputStream(fileName);
TextReadFile.showAvailableBytes(in);
while((byteread = in.read(temptypes))!=-1){
System.out.write(temptypes, 0, byteread);
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
if(in != null){
try {
in.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
/*
* 显示输入六中还剩的字节数
*/
public static void showAvailableBytes(InputStream in){
try {
System.out.println("当前字节输入流中的字节数为："+in.available());
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/*
* 义字符为单位读取
*/
public static void readFileByChar(String fileName){
File file = new File(fileName);
Reader read = null;
System.out.println("3、以字符为单位读取文件内容，一次读一个字节：");
try {
read = new InputStreamReader(new FileInputStream(file));
int tempchar;
while((tempchar= read.read())!=-1){
if((char)tempchar!=‘r‘){
System.out.print((char)tempchar);
}
}
read.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("4.一字符为单位读取文件内容，一次读取多个：");
char[] tempchars = new char[1024];
int charread = 0;
try {
read = new InputStreamReader(new FileInputStream(file));
while((charread=read.read(tempchars))!=-1){
if((charread == tempchars.length)&&(tempchars[tempchars.length-1]!=‘r‘)){
System.out.print(tempchars);
}else{
for(int i = 0;i<charread;i++){
if(tempchars[i]==‘r‘){
continue;
}else{
System.out.print(tempchars[i]);
}
}
}
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
if(read != null){
try {
read.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
/*
* 读一行
*/
public static void readFileByLine(String fileName){
File file = new File(fileName);
BufferedReader reader = null;
System.out.println("6.以行为为单位读取文件内容，一次读一行：");
try {
reader = new BufferedReader(new FileReader(file));
String tempString = null;
int line = 1;
while((tempString = reader.readLine())!=null){
System.out.println("line"+line+":"+tempString);
line++;
}
reader.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
if(reader!= null){
try {
reader.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
public static void main(String[] args) {
String fileName = "D:/Desktop/JarCode.txt";
System.out.println("1.按字节为单位读取文件：");
readFileByBytes(fileName);
System.out.println("1.按字符为单位读取文件：");
readFileByChar(fileName);
System.out.println("1.按行为单位读取文件：");
readFileByLine(fileName);
}
}