Java—对象序列化，反序列化，IO框架

接上篇：Java-IO流文件操作，编码转换_郑*杰的博客-优快云博客

注意事项，如代码注释

import java.io.Serializable;
//对象想被序列化，需要继承Serializable接口
public class Student implements Serializable {
    public static final long serialVersionUID = 1; // 版本号，序列化前后版本号需要保持一致，如果反序列化因版本号失败，重新序列化一次即可
    private String name;
    // 某个字段不想被序列化，加transient
    private transient String sex;
    private int age;

    public Student(String name, String sex, int age) {
        this.name = name;
        this.sex = sex;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", sex='" + sex + '\'' +
                ", age=" + age +
                '}';
    }
}

序列化操作

import java.io.*;

public class ObjectOutstreamdemo {
    public static void main(String[] args) throws Exception {
        Student s = new Student("小明","男" , 10);
        OutputStream out = new FileOutputStream("file-io-serialization\\obj.txt");
        ObjectOutputStream objectout = new ObjectOutputStream(out);//使用对象输出流包装原始流
        objectout.writeObject(s);
        objectout.close();
        System.out.println("序列化成功");

        //反序列化同理
        InputStream in = new FileInputStream("file-io-serialization\\obj.txt");
        ObjectInputStream objectin = new ObjectInputStream(in);
        Student ss = (Student) objectin.readObject();
        System.out.println(ss);
        objectin.close();
        System.out.println("反序列化成功");

    }
}

打印流，写入数据最高效方便

import java.io.*;

public class Printsteamdemo {
    public static void main(String[] args) throws Exception {

        PrintStream ps = new PrintStream("file-io-serialization/write.txt");
        PrintStream ps2 = new PrintStream(new FileOutputStream("file-io-serialization/write.txt",true));
        PrintWriter ps1 = new PrintWriter("file-io-serialization\\write.txt");
        ps.println("任意数据写入");
        ps1.println("任意数据写入");
    }
}

重定向打印流，可以将本来输出到控制台输出到指定文件

import java.io.*;

public class Printsteamdemo {
    public static void main(String[] args) throws Exception {
        PrintStream ps = new PrintStream("file-io-serialization/log.log");
        System.setOut(ps);
        System.out.println("重定向输出");
    }
}

Properties用于读取配置文件

import java.io.FileReader;
import java.io.FileWriter;
import java.util.Properties;

public class Propretiesdemo {
    public static void main(String[] args) throws Exception {
        Properties  p = new Properties();
        p.setProperty("中文","1");
        p.setProperty("B","2");
        p.setProperty("C","3");
        p.setProperty("D","4");
        p.store(new FileWriter("file-io-serialization\\write.properties"),"这是个注释，将键值对保存到配置文件，后缀需要是properties");
        p.load(new FileReader("file-io-serialization\\write.properties"));
        System.out.println("读取内容"+p.getProperty("中文"));
    }
}

第三方IO框架，更加常用，之前文章用于基础了解，可进一步理解IO框架的原理

1、下载第三方jar包：Commons IO – Download Apache Commons IO

 2、解压包得到：commons-io-2.11.0.jar，在项目模块中创建lib目录放入，然后添加到依赖版本即可使用，FileUtils更加方便简洁

import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;

import java.io.*;

public class Iouitodemo {
    public static void main(String[] args) throws Exception {
        FileUtils.copyFile(new File("D:\\zhengqinjie\\logback-classic-1.2.3.jar"),new File("D:\\zhengqinjie\\新建文件夹\\3.jar"));
        String reader = FileUtils.readFileToString(new File("D:\\zhengqinjie\\新建文件夹\\1建.txt"),"utf-8");
        System.out.println(reader);
        FileUtils.copyDirectoryToDirectory(new File("D:\\zhengqinjie"),new File("D:\\zhengqinjie1"));
        FileUtils.deleteDirectory(new File("D:\\zhengqinjie1"));
        IOUtils.copy(new FileInputStream("D:\\zhengqinjie\\logback-classic-1.2.3.jar"),new FileOutputStream("D:\\zhengqinjie\\los.3.jar") );
       
    }
}