Java 其他流
节点流
字节数组节点流
-
输入流:ByteArrayInputStream read(byte[] b,int off,int len) close() 不用关闭
-
输出流:ByteArrayOutputStream write(byte[] b,int off,int len) toByteArray()
import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
public class Demo08 {
public static void main(String[] args) throws IOException {
read(write());
}
public static void read(byte[] src) throws IOException {
//选择流
InputStream is = new BufferedInputStream(new ByteArrayInputStream(src));
//操作
byte[] flush = new byte[1024];
int len = 0;
while(-1!=(is.read(flush))){
System.out.println(new String(flush));
}
}
public static byte[] write(){
//目的地
byte[] dest;
//选择流
ByteArrayOutputStream bos = new ByteArrayOutputStream();
//操作写出
String msg = "操作与文件输入流一致";
byte[] info = msg.getBytes();
bos.write(info,0,info.length);
//获取数据
dest = bos.toByteArray();
return dest;
}
}import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
/**
*1、文件 --程序->字节数组
*1)、文件输入流
* 字节数组输出流
*
*
* 2、字节数组 --程序->文件
* 1)、字节数组输入流
* 文件输出流
* @author Administrator
*
*/
public class ByteArrayDemo02 {
/**
* @param args
* @throws IOException
*/
public static void main(String[] args) throws IOException {
byte[] data =getBytesFromFile("e:/xp/test/1.jpg");
toFileFromByteArray(data,"e:/xp/test/arr.jpg");
}
/**
* 2、字节数组 --程序->文件
*/
public static void toFileFromByteArray(byte[] src,String destPath) throws IOException{
//创建源
//目的地
File dest=new File(destPath);
//选择流
//字节数组输入流
InputStream is =new BufferedInputStream(new ByteArrayInputStream(src));
//文件输出流
OutputStream os =new BufferedOutputStream(new FileOutputStream(dest));
//操作 不断读取字节数组
byte[] flush =new byte[1];
int len =0;
while(-1!=(len =is.read(flush))){
//写出到文件中
os.write(flush, 0, len);
}
os.flush();
//释放资源
os.close();
is.close();
}
/**
* 1、文件 --程序->字节数组
* @return
* @throws IOException
*/
public static byte[] getBytesFromFile(String srcPath) throws IOException{
//创建文件源
File src =new File(srcPath);
//创建字节数组目的地
byte[] dest =null;
//选择流
//文件输入流
InputStream is =new BufferedInputStream(new FileInputStream(src));
//字节数组输出流 不能使用多态
ByteArrayOutputStream bos =new ByteArrayOutputStream();
//操作 不断读取文件 写出到字节数组流中
byte[] flush =new byte[1024];
int len =0;
while(-1!=(len =is.read(flush))){
//写出到字节数组流中
bos.write(flush, 0, len);
}
bos.flush();
//获取数据
dest =bos.toByteArray();
bos.close();
is.close();
return dest;
}
}处理流
基本数据类型处理流
基本数据类型+String 保留数据+类型
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
/**
* 1.输入流:DataInputStream
* 2.输出流:DataOutputStream
* java.io.EOFException :没有读取到相关的内容
* @author Matrix42
*
*/
public class Demo09 {
public static void main(String[] args) throws IOException {
write("F:/data.txt");
read("F:/data.txt");
}
/**
* 从文件读取数据+类型
* @throws IOException
*/
public static void read(String destPath) throws IOException{
//创建源
File src = new File(destPath);
//选择流
DataInputStream dis = new DataInputStream(
new BufferedInputStream(
new FileInputStream(src)));
//操作 读取顺序与写入顺序一致 必须存在才能读取
double point = dis.readDouble();
long num = dis.readLong();
String str = dis.readUTF();
dis.close();
System.out.println(point+" "+num+" "+str);
}
public static void write(String destPath) throws IOException {
double point = 2.5;
long num = 100L;
String str = "数据类型";
//创建源
File dest = new File(destPath);
//选择流
DataOutputStream dos = new DataOutputStream(
new BufferedOutputStream(
new FileOutputStream(dest)));
//操作 写出的顺序 为读取准备
dos.writeDouble(point);
dos.writeLong(num);
dos.writeUTF(str);
dos.flush();
dos.close();
}
}引用数据类型处理流
-
反序列化:ObjectInputStream readObject()
-
序列化:ObjectOutputStream writeObject()
反序列化顺序必须和反序列化一致
不是所有的对象都可以系列化,需要实现java.io.Serializable
不是所有的属性都需要序列化,使用transient表示这个属性不需要序列化
/**
* 空接口只是标识
*/
public class Employee implements java.io.Serializable {
//不需要序列化
private transient String name;
private double salary;
public Employee() {
}
public Employee(String name, double salary) {
super();
this.name = name;
this.salary = salary;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getSalary() {
return salary;
}
public void setSalary(double salary) {
this.salary = salary;
}
}import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
public class Demo10 {
public static void main(String[] args) throws FileNotFoundException, IOException, ClassNotFoundException {
ser("F:ser.txt");
read("F:ser.txt");
}
public static void read(String destPath) throws FileNotFoundException, IOException, ClassNotFoundException{
File dest = new File(destPath);
ObjectInputStream dis = new ObjectInputStream(
new BufferedInputStream(
new FileInputStream(dest)));
Object object = dis.readObject();
if (object instanceof Employee) {
Employee employee = (Employee) object;
System.out.println(employee.getName());
System.out.println(employee.getSalary());
}
dis.close();
}
public static void ser(String destPath) throws FileNotFoundException, IOException{
Employee emp = new Employee("me",10000);
File dest = new File(destPath);
ObjectOutputStream dos = new ObjectOutputStream(
new BufferedOutputStream(
new FileOutputStream(dest)));
dos.writeObject(emp);
dos.close();
}
}1.7新特性
- try-with-resource
try(代码){
关闭流
}catch(){
}打印流
重定向输出到文件
import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintStream;
public class Demo11 {
public static void main(String[] args) throws FileNotFoundException {
File src = new File("F:/out.txt");
PrintStream ps = new PrintStream(src);
ps.print("123");
}
}import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileDescriptor;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.PrintStream;
import java.util.Scanner;
/**
* 三个常量
* 1、System.in 输入流 键盘输入
* 2、System.out 输出流 控制台输出
* System.err
*
* ==>重定向
* setIn()
* setOut()
* setErr()
* FileDescriptor.in
* FileDescriptor.out
* @author Administrator
*
*/
public class SystemDemo01 {
/**
* @param args
* @throws FileNotFoundException
*/
public static void main(String[] args) throws FileNotFoundException {
//test1();
//test2();
//重定向
System.setOut(new PrintStream(new BufferedOutputStream(new FileOutputStream("e:/xp/test/print.txt")),true));
System.out.println("a"); //控制台 -->文件
System.out.println("test");
//回控制台
System.setOut(new PrintStream(new BufferedOutputStream(new FileOutputStream(FileDescriptor.out)),true));
System.out.println("back....");
}
public static void test2() throws FileNotFoundException{
InputStream is =System.in; //键盘输入
is = new BufferedInputStream(new FileInputStream("e:/xp/test/print.txt"));
Scanner sc = new Scanner(is);
//System.out.println("请输入:");
System.out.println(sc.nextLine());
}
public static void test1(){
System.out.println("test");
System.err.println("err");
}
}装饰设计模式
处理流就是对节点流的包装
public class Voice {
private int voice =10;
public Voice() {
}
public int getVoice() {
return voice;
}
public void setVoice(int voice) {
this.voice = voice;
}
public void say(){
System.out.println(voice);
}
}/**
* 扩音器
* 类与类之间的关系
* 1、依赖:形参|局部变量
* 2、关联:属性
* 聚合:属性 整体与部分 不一致的生命周期 人与手
* 组合:属性 整体与部分 一致的生命周期 人与大脑
* 3、继承:父子类关系
* 4、实现: 接口与实现类关系
*/
public class Amplifier {
private Voice voice;
public Amplifier() {
}
public Amplifier(Voice voice) {
super();
this.voice = voice;
}
public void say(){
System.out.println(voice.getVoice()*1000);
}
}文件的分割与合并
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.io.SequenceInputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.Vector;
import com.bjsxt.io.util.FileUtil;
public class SplitFile {
//文件的路径
private String filePath;
//文件名
private String fileName;
//文件大小
private long length;
//块数
private int size;
//每块的大小
private long blockSize;
//分割后的存放目录
private String destBlockPath;
//每块的名称
private List<String> blockPath;
public SplitFile(){
blockPath = new ArrayList<String>();
}
public SplitFile(String filePath,String destBlockPath){
this(filePath,destBlockPath,1024);
}
public SplitFile(String filePath,String destBlockPath,long blockSize){
this();
this.filePath= filePath;
this.destBlockPath =destBlockPath;
this.blockSize=blockSize;
init();
}
/**
* 初始化操作 计算 块数、确定文件名
*/
public void init(){
File src =null;
//健壮性
if(null==filePath ||!(((src=new File(filePath)).exists()))){
return;
}
if(src.isDirectory()){
return ;
}
//文件名
this.fileName =src.getName();
//计算块数 实际大小 与每块大小
this.length = src.length();
//修正 每块大小
if(this.blockSize>length){
this.blockSize =length;
}
//确定块数
size= (int)(Math.ceil(length*1.0/this.blockSize));
//确定文件的路径
initPathName();
}
private void initPathName(){
for(int i=0;i<size;i++){
this.blockPath.add(destBlockPath+"/"+this.fileName+".part"+i);
}
}
/**
* 文件的分割
* 0)、第几块
* 1、起始位置
* 2、实际大小
* @param destPath 分割文件存放目录
*/
public void split(){
long beginPos =0; //起始点
long actualBlockSize =blockSize; //实际大小
//计算所有块的大小、位置、索引
for(int i=0;i<size;i++){
if(i==size-1){ //最后一块
actualBlockSize =this.length-beginPos;
}
spiltDetail(i,beginPos,actualBlockSize);
beginPos+=actualBlockSize; //本次的终点，下一次的起点
}
}
/**
* 文件的分割 输入 输出
* 文件拷贝
* @param idx 第几块
* @param beginPos 起始点
* @param actualBlockSize 实际大小
*/
private void spiltDetail(int idx,long beginPos,long actualBlockSize){
//1、创建源
File src = new File(this.filePath); //源文件
File dest = new File(this.blockPath.get(idx)); //目标文件
//2、选择流
RandomAccessFile raf = null; //输入流
BufferedOutputStream bos=null; //输出流
try {
raf=new RandomAccessFile(src,"r");
bos =new BufferedOutputStream(new FileOutputStream(dest));
//读取文件
raf.seek(beginPos);
//缓冲区
byte[] flush = new byte[1024];
//接收长度
int len =0;
while(-1!=(len=raf.read(flush))){
if(actualBlockSize-len>=0){ //查看是否足够
//写出
bos.write(flush, 0, len);
actualBlockSize-=len; //剩余量
}else{ //写出最后一次的剩余量
bos.write(flush, 0, (int)actualBlockSize);
break;
}
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}finally{
FileUtil.close(bos,raf);
}
}
/**
* 文件的合并
*/
public void merge(String destPath){
//创建源
File dest =new File(destPath);
//选择流
BufferedOutputStream bos=null; //输出流
SequenceInputStream sis =null ;//输入流
//创建一个容器
Vector<InputStream> vi = new Vector<InputStream>();
try {
for (int i = 0; i < this.blockPath.size(); i++) {
vi.add(new BufferedInputStream(new FileInputStream(new File(this.blockPath.get(i)))));
}
bos =new BufferedOutputStream(new FileOutputStream(dest,true)); //追加
sis=new SequenceInputStream(vi.elements());
//缓冲区
byte[] flush = new byte[1024];
//接收长度
int len =0;
while(-1!=(len=sis.read(flush))){
bos.write(flush, 0, len);
}
bos.flush();
FileUtil.close(sis);
} catch (Exception e) {
}finally{
FileUtil.close(bos);
}
}
/**
* 文件的合并
*/
public void merge1(String destPath){
//创建源
File dest =new File(destPath);
//选择流
BufferedOutputStream bos=null; //输出流
try {
bos =new BufferedOutputStream(new FileOutputStream(dest,true)); //追加
BufferedInputStream bis = null;
for (int i = 0; i < this.blockPath.size(); i++) {
bis = new BufferedInputStream(new FileInputStream(new File(this.blockPath.get(i))));
//缓冲区
byte[] flush = new byte[1024];
//接收长度
int len =0;
while(-1!=(len=bis.read(flush))){
bos.write(flush, 0, len);
}
bos.flush();
FileUtil.close(bis);
}
} catch (Exception e) {
}finally{
FileUtil.close(bos);
}
}
public static void main(String[] args) {
SplitFile split = new SplitFile("E:/xp/20130502/test/学员设置(20130502).xls","E:/xp/20130502",51);
//System.out.println(split.size);
//split.split();
split.merge("E:/xp/20130502/test1.xls");
}
}