1.IO流
2. 1字节流(一切皆为字节)
字节输出流
public static void main(String
[] args
) throws IOException
{
FileOutputStream fos
=new FileOutputStream("E:\\javacode\\111\\src\\io\\a.txt");
fos
.write(97);
fos
.write(97);
byte[] b1
= {65,66,65,67};
fos
.write(b1
);
fos
.close();
FileOutputStream fos1
=new FileOutputStream(new File("E:\\javacode\\111\\src\\io\\b.txt"));
fos1
.write(97);
fos1
.write(97);
fos1
.write(b1
, 1, 2);
byte[] b2
="你好".getBytes();
System
.out
.println(Arrays
.toString(b2
));
fos1
.write(b2
);
fos1
.close();
}
FileOutputStream fos
=new FileOutputStream("E:\\javacode\\111\\src\\io\\a.txt", true);
for (int i
= 0; i
< 3; i
++) {
fos
.write("你好".getBytes());
fos
.write("\r\n".getBytes());
}
fos
.close();
字节输入流
public static void main(String
[] args
) throws IOException
{
FileInputStream fis
= new FileInputStream("E:\\javacode\\111\\src\\io\\b.txt");
int a
=0;
while ((a
=fis
.read())!=-1) {
System
.out
.println(a
);
}
fis
.close();
}
public static void main(String
[] args
) throws IOException
{
FileInputStream fis
= new FileInputStream("E:\\javacode\\111\\src\\io\\b.txt");
byte[] bytes
=new byte[1024];
int len
=0;
while ((len
=fis
.read(bytes
))!=-1) {
System
.out
.println(new String(bytes
,0,len
));
}
fis
.close();
}
public static void main(String
[] args
) throws IOException
{
FileOutputStream fos
=new FileOutputStream("E:\\javacode\\111\\src\\io\\aa.txt");
FileInputStream fis
= new FileInputStream("C:\\Users\\THINK\\Desktop\\ps.txt");
byte[] bytes
=new byte[1024];
int len
=0;
while ((len
=fis
.read(bytes
))!=-1) {
fos
.write(bytes
,0,len
);
}
fos
.close();
fis
.close();
}
2.2 字符流
字符流读取文件
public static void main(String
[] args
) throws IOException
{
FileReader fr
= new FileReader("E:\\javacode\\111\\src\\io\\a.txt");
char[] bytes
= new char[1024];
int len
= 0;
while ((len
= fr
.read(bytes
)) != -1) {
System
.out
.println(new String(bytes
,0,len
));
}
fr
.close();
}
字符流写入数据
public static void main(String
[] args
) throws IOException
{
FileWriter fw
= new FileWriter("E:\\javacode\\111\\src\\io\\d.txt");
fw
.write(99);
char[] b
= {'a','2','3','-','-'};
fw
.write(b
);
fw
.write("你好!");
fw
.write("你好!",2,1);
fw
.flush();
fw
.close();
}
**
属性集
Properties类表示一个持久层的属性集。Properties可保存在流中或从流中加载
Properties集合是一个唯一和IO流相结合的集合
可以使用Properties集合中的方法store,把集合中的临时数据,持久化写入到硬盘中存储
可以使用Properties集合中load,把硬盘中保存的文件(键值对),读到集合中使用
属性列表中每个键及其对应值都是一个字符串
Properties集合是一个双列集合,key和value默认都是字符串
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