#千锋逆战班#

最新推荐文章于 2020-03-17 22:28:57 发布

原创最新推荐文章于 2020-03-17 22:28:57 发布 · 164 阅读

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在千锋学习的第31天

继续努力

今天学习了IO 框架了解了各种流，

（流的分类）对于FileInputStream 来说，从方向上说，输入流，从数据单位上分，为字节流，功能上分，为节点流

（字节流） FileInputStream 三个重载的read方法

1无参的read 方法返回值为int 表示获取字节的ASCll值

2 int read(byte[] bs) 方法返回读入缓冲区的字节总数，表示存储读取数据的缓冲区

3 读入缓冲区的字节数 bs 存储读取数据的缓冲区 off 目标数组bs de从哪开始 len 读取的最大字节数

5  AB

1 1) 创建文件  如果已经存下则会创建新的文件并覆盖

2）在后面追加数据   会产生异常

public class TestFileInputStream {

	public static void main(String[] args) throws IOException //抛出异常{
		
		Fil OutputStream flo =new FileOutputStream("test.txt");



            try{

                System.out.println(fin.read());
                    fin.close;

}catch (Exception e){
        
}
}
}

package com.lichenchen.t1;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class TestFileInputStream {

	public static void main(String[] args) throws IOException {
		
		FileOutputStream flo =new FileOutputStream("test.txt",true);
		String str ="Hello Word";
		byte [] b =str.getBytes();
		
		flo.write(b);
		
		
		
		FileInputStream fin =new FileInputStream ("D:\\eclipse\\day33\\test.txt");
		while(true){
			int cou=fin.read();
			if(cou==-1){
				break;
			}
			System.out.print((char)cou);
		}
		System.out.println();
		
		
		
		try{
		byte [] bytes =new byte[4];
		while(true){
			int count =fin.read(bytes);
			if(count==-1){
				break;
			}
			for(int i=0;i<bytes.length;i++){
				System.out.print((char)bytes[i]);
			}
			System.out.println();
		}
		}catch (Exception e){
			
		}finally{
			fin.close();
		}
		
		
		
		
		

	}

}

为了让某对象实现序列化，要求实现Serializable 接口

为了 让某个对象属性不参与序列化，应当使用transient

区别：print（Object obj） 打印一个对象Obj
writeObject（Object obj）将对象obj写入ObjectOutputStream
中

package com.lichenchen.t1;
import java.io.*;
public class TestSerializable {

	public static void main(String[] args) throws IOException {
		Address addr =new Address("beijing","10000");
		Worker  w= new Worker("Tom",18,addr);
		OutputStream os =new FileOutputStream("data.text");
	ObjectOutputStream out =new ObjectOutputStream(os);
	out.writeObject(w);
	out.close();
	
	
	}
	

}
class Address implements Serializable{
	private String addressName;
	private String zipCode;
	public Address(String addressName, String zipCode) {
		super();
		this.addressName = addressName;
		this.zipCode = zipCode;
	}
	public String getAddressName() {
		return addressName;
	}
	public void setAddressName(String addressName) {
		this.addressName = addressName;
	}
	public String getZipCode() {
		return zipCode;
	}
	public void setZipCode(String zipCode) {
		this.zipCode = zipCode;
	}
	
}


class Worker implements Serializable{
	private String name;
	private int age;
	private Address address;
	public Worker(String name, int age, Address address) {
		super();
		this.name = name;
		this.age = age;
		this.address = address;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public Address getAddress() {
		return address;
	}
	public void setAddress(Address address) {
		this.address = address;
	}
	
}

B  Address 没有实现Serializable接口  不能实现序列化