字节流
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-------------------------------------------------字节读取---------------------------------------
public class Test {
public static void main(String[] args) throws IOException {
FileInputStream fis = new FileInputStream("fis.txt");
//一次读取一个字节
int by = 0 ;
while((by=fis.read())!= -1){
System.out.println((char)by);
}
//一次读取一个字节数组
byte[] bys = new byte[1024] ;
int len = 0 ;
while((len=fis.read(bys)) != -1){
System.out.println(new String(bys,0,len));
}
fis.close() ;
}
}
inputstream--------------------------------------------------------- outputstream // 输入输出是相对的,这里是相对于Java程序来讲
读取文件 :
File file = new File(“C:/b.txt”);
InputStream inputstream = null ;
try {
inputstream = new FileInputStream(file);
byte[] b = new byte[1024] ;
int len = 0;
while( (len =inputstream.read(b)) != -1 ){
String s = new String(b,0,len);
System.out.println(s);
}} catch (FileNotFoundException e) {
System.out.println("没找到文件");
} catch (IOException e) {
System.out.println("文件写入失败");
}finally{
try {
if(inputstream != null){
inputstream.close();
}
} catch (IOException e) {
System.out.println("输入流关闭失败");
}}
写文件:
File file = new File("D:/a/b/d.txt");-----------// 如果没有该文件, jvm 会自己创建文件,(可是当你只是File ,没有下面操作时,是不会自己创建的)
OutputStream outputStream = null ;
try {
outputStream = new FileOutputStream(file,true); -------------默认为 false ,设置为true ,是在原有文件的文档基础上添加你要写的东西,false是覆盖原文
String s = "你到底猜不猜 ";
byte[] b = s.getBytes();
outputStream.write(b);
} catch (FileNotFoundException e) {
System.out.println("没找到文件");
} catch (IOException e) {
System.out.println("写入失败");
}finally{
try {
if( outputStream != null){
outputStream.close();
}
} catch (IOException e) {
System.out.println("关闭失败");
}
}