@Test
public void copyByBytes() throws IOException {
String root = FileTests.class.getResource("/").getPath();
FileInputStream fis = new FileInputStream(new File(root,"/start.bat"));
FileOutputStream fos = new FileOutputStream(root+"/out2.bat");
byte[] buff = new byte[100];int b;
while ((b = fis.read(buff))!=-1){
fos.write(buff,0, b);}// close
}
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文件合并
@Test
public void mergeFiles() throws IOException {
File file1 = new File("E:\\_projects\\sucls\\blog\\my_study\\guava\\guava-io\\src\\test\\java\\com\\sucls\\blog\\guava\\io\\category\\FileTests.java");
File file2 = new File("E:\\_projects\\sucls\\blog\\my_study\\guava\\guava-io\\src\\test\\java\\com\\sucls\\blog\\guava\\io\\category\\StreamTests.java");
Enumeration<InputStream> ins = Collections.enumeration(Arrays.asList(
new FileInputStream(file1),
new FileInputStream(file2)));
SequenceInputStream sequenceInputStream = new SequenceInputStream(ins);
FileOutputStream fos = new FileOutputStream(root+"/out4");
byte[] buff = new byte[100];int read;// 真实读取到的字节数
while ((read = sequenceInputStream.read(buff))!=-1){
fos.write(buff,0, read);}
fos.close();}
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读取文件内容为字符串
@Test
public void readStringFromFile() throws IOException {
FileReader fileReader = new FileReader(new File(this.getClass().getResource("/").getPath(),"/start.bat"));
StringBuilder stringBuilder = new StringBuilder();int i;
while ((i = fileReader.read())!=-1){
stringBuilder.append((char)i );// 按字符读取
}
System.out.println( stringBuilder );// 文件内容
}
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字节数组转换成流
@Test
public void bytesToStream(){
byte [] data = new byte[1024];// 来源于其他数据源
ByteArrayInputStream inputStream = new ByteArrayInputStream(data);
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();int v;
while ((v=inputStream.read())!=-1){
outputStream.write(v);}
System.out.println( Arrays.toString( outputStream.toByteArray()));}
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对象序列化与反序列化
@Test
public void objectToFile() throws IOException {
Person person = new Person();
person.setName("张三").setAge(25);
String root = FileTests.class.getResource("/").getPath();
FileOutputStream fos = new FileOutputStream(new File(root,"/person"));
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(person);}
@Test
public void fileToObject() throws IOException, ClassNotFoundException {
String root = FileTests.class.getResource("/").getPath();
FileInputStream fis = new FileInputStream(new File(root,"/person"));
ObjectInputStream ois = new ObjectInputStream(fis);
Person person =(Person) ois.readObject();
System.out.println( person );}
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流的转换 将字节流转换成字符流来操作，同样以文件复制为例
@Test
public void copyByBuffer() throws IOException {
String root = FileTests.class.getResource("/").getPath();
FileInputStream fis = new FileInputStream(new File(root,"/start.bat"));
InputStreamReader isr = new InputStreamReader(fis);
BufferedReader br = new BufferedReader(isr);
FileOutputStream fos = new FileOutputStream(root+"/out3.bat");
OutputStreamWriter osw = new OutputStreamWriter(fos);
BufferedWriter bw = new BufferedWriter(osw);
String line;
while ((line = br.readLine())!=null){
bw.append(line);
bw.newLine();
bw.flush();}// close
}
