JAVASE进阶day11（IO流（字符流），编码格式，序列化）

字符编码

1.编码解码

2.字符集(码表) 

3.常见编码规则 

4.Java中的编解码方法

IO字符流

1.字符流读的基本使用

package com.lu.day11.test;
 
import java.io.FileReader;
import java.io.IOException;
 
public class Test {
    public static void main(String[] args) {
        try(FileReader fileReader = new FileReader("resource/b.txt");) {
 
            char[] chars = new char[1024];
            int read;
            while ((read = fileReader.read(chars)) != -1) {
                System.out.println(new String(chars, 0, read));
 
            }
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}

2.字符流写的基本使用

package com.lu.day11.test;
 
import java.io.FileWriter;
import java.io.IOException;
 
public class Test1 {
    public static void main(String[] args) {
        try (FileWriter fileWriter = new FileWriter("resource/a.txt");){
 
            fileWriter.write("hello");
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}

3.BufferedReader

package com.lu.day11.test;
 
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
 
public class Test {
    public static void main(String[] args) {
        try(BufferedReader bufferedReader = new BufferedReader(new FileReader("resource/b.txt"))) {
            //判断是否读取结束
            while (bufferedReader.ready()){
                //读取一行
                System.out.println(bufferedReader.readLine());
 
                //jdk8新特性
                //bufferedReader.lines().forEach(System.out::println);
            }
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}

4.BufferedWriter

package com.lu.day11.test;
 
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
 
public class Test1 {
    public static void main(String[] args) {
        try ( BufferedWriter bufferedWriter = new BufferedWriter( new FileWriter("resource/a.txt",true))){
 
            bufferedWriter.write("hello world");
            //换行屏蔽不同操作系统差异性
            bufferedWriter.newLine();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}

序列化反序列化

 1.序列化的基本使用

package com.lu.day11.test;
 
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
 
public class Test2 {
    public static void main(String[] args) {
        try(ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream("student.txt"));){
            out.writeObject(new Student("张三", 18));
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}

package com.lu.day11.test;
 
import java.io.Serializable;
//使用序列化要使用Serializable接口
public class Student implements Serializable {
    private String name;
    private int age;
 
    public Student(String name, int age) {
        this.name = name;
        this.age = age;
    }
 
    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;
    }
}

2.反序列化的基本使用

package com.lu.day11.test;
 
import java.io.FileInputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.util.ArrayList;
 
public class Test3 {
    public static void main(String[] args) {
        try(ObjectInputStream in = new ObjectInputStream(new FileInputStream("student.txt"))){
            ArrayList<Student> o = (ArrayList<Student>) in.readObject();
            System.out.println(o);
        } catch (IOException | ClassNotFoundException e) {
            throw new RuntimeException(e);
        }
    }
}

package com.lu.day11.test;
 
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.util.ArrayList;
 
public class Test2 {
    public static void main(String[] args) {
        try(ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream("student.txt"));){
            ArrayList<Student> list = new ArrayList<>();
            list.add(new Student("李四", 19));
            out.writeObject(list);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}

Properties

1.properties写

package com.lu.day11.test;
 
import java.io.FileWriter;
import java.util.Properties;
 
public class Test4 {
    public static void main(String[] args) {
        Properties properties = new Properties();
        properties.setProperty("name", "lu");
        properties.setProperty("age", "18");
        try (FileWriter fileWriter = new FileWriter("resource/test.properties");){
            //comments 注释在文件里中文会保存为unicode编码
            //.properties
            properties.store(fileWriter, "这是练习");
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
}

2.properties读 

package com.lu.day11.test;
 
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.Properties;
 
public class Test5 {
    public static void main(String[] args) {
        Properties properties = new Properties();
        try( FileReader fileReader = new FileReader("resource/test.properties");){
            properties.load(fileReader);
            properties.forEach((k,v)->System.out.println(k+"--->"+v));
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}