标签：book pytho io流 null row software 开始 cat block
本文是基于Linux环境运行，读者阅读前需要具备一定Linux知识
InputStream包含如下三个方法：
FileInputStream继承InputStream，使用FileInputStream读取文件内容
代码1-1
import java.io.FileInputStream;
import java.io.IOException;
public class FileInputStreamTest {
public static void main(String[] args) {
if (args == null || args.length == 0) {
throw new RuntimeException("请输入路径");
}
FileInputStream fis = null;
try {
byte[] bbuf = new byte[1024];
int hasRead = 0;
fis = new FileInputStream(args[0]);
while ((hasRead = fis.read(bbuf)) > 0) {
System.out.print(new String(bbuf, 0, hasRead));
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
try {
if (fis != null) {
fis.close();
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
代码1-1运行结果：
root@lejian:/home/software/.io# cat text Hello Spring Hello Hibernate Hello MyBatis root@lejian:/home/software/.io# java FileInputStreamTest text Hello Spring Hello Hibernate Hello MyBatis
Reader包含如下三个方法：
FileReader的父类继承自Reader，使用FileReader读取文件
代码1-2
import java.io.FileReader;
import java.io.IOException;
public class FileReaderTest {
public static void main(String[] args) {
if (args == null || args.length == 0) {
throw new RuntimeException("请输入路径");
}
FileReader fr = null;
try {
fr = new FileReader(args[0]);
char[] cbuf = new char[32];
int hasRead = 0;
while ((hasRead = fr.read(cbuf)) > 0) {
System.out.print(new String(cbuf, 0, hasRead));
}
} catch (IOException e) {
// TODO: handle exception
e.printStackTrace();
} finally {
try {
if (fr != null) {
fr.close();
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
代码1-2运行结果：
root@lejian:/home/software/.io# cat text Java编程思想 算法 编译原理 root@lejian:/home/software/.io# java FileReaderTest text Java编程思想 算法 编译原理
代码1-3
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
public class FileOutputStreamTest {
public static void main(String[] args) {
if (args == null || args.length < 2) {
throw new RuntimeException("请输入两个路径");
}
FileInputStream fis = null;
FileOutputStream fos = null;
try {
fis = new FileInputStream(args[0]);
fos = new FileOutputStream(args[1]);
byte[] bbuf = new byte[32];
int hasRead = 0;
while ((hasRead = fis.read(bbuf)) > 0) {
fos.write(bbuf, 0, hasRead);
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
try {
if (fis != null) {
fis.close();
}
if (fos != null) {
fos.close();
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
OutputStream和Writer：
Writer里还包含如下两个方法：
使用FileInputStream来执行输入，FileOutputStream来执行输出
代码1-3运行结果：
root@lejian:/home/software/.io# cat input Java编程思想 算法 编译原理 root@lejian:/home/software/.io# cat output root@lejian:/home/software/.io# java FileOutputStreamTest input output root@lejian:/home/software/.io# cat output Java编程思想 算法 编译原理
使用FileWriter来执行输出
代码1-4
import java.io.FileWriter;
import java.io.IOException;
public class FileWriterTest {
public static void main(String[] args) {
if (args == null || args.length == 0) {
throw new RuntimeException("请输入路径");
}
FileWriter fw = null;
try {
fw = new FileWriter(args[0]);
fw.write("数据结构与算法\n");
fw.write("Python基础教程\n");
fw.write("C和指针\n");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
try {
if (fw != null) {
fw.close();
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
代码1-4运行结果：
root@lejian:/home/software/.io# cat book root@lejian:/home/software/.io# java FileWriterTest book root@lejian:/home/software/.io# cat book 数据结构与算法 Python基础教程 C和指针
Java7之后，很多IO资源类都实现了AutoCloseable接口，只要在try语句中声明的IO流都可以自动关闭，但有一些IO流像FileWriter这样的输出流，如果IO流不显示的关闭，输出流缓冲区的数据无法flush到实际的物理节点，因为执行IO流的close()方法前，会先执行flush()方法
FileInputStream、FileReader、FileInputStream、FileWriter使用小结
标签：book pytho io流 null row software 开始 cat block
原文地址：http://www.cnblogs.com/baoliyan/p/6220092.html
