标签：append load port fileread tag 输入流 系统 通过 code
今天系统的学习了 Java IO 这部分的知识，把一些之前没有用过的，或者忘记的方法和类重新学了一下。怕自己睡一觉把今天学的忘完了QaQ。所以，不得已写一下博客
IO概述
package com.coder.com;
import java.io.*;
import java.nio.charset.StandardCharsets;
public class Demo01 {
/**
* IO流概述
* 可以将数据传输的操作看成一种数据的流动,按照流动的方向可以分为输入Input和输出Output
* Java中的IO操作主要指的是 java.io包下的一些常用类的使用， 通过这些类可以对数据进行读取（输入流）和写出（输出流）
* <p>
* IO流分类:
* 按照方向：
* - 输入流
* - 输出流
* 按照数据类型:
* - 字节流
* -输入 InputStream
* -输出 OutputStream
* - 字符流
* -输入 Reader
* -输出 Writer
* 一切皆字节:
* 计算机中的任何数据都是以二进制形式存储的
* 传输时也是以二进制的形式传输的
*</p>
* @param args
*/
public static void main(String[] args) throws IOException {
//字节流
OutputStream os = new FileOutputStream("E:\\a.txt", true);
os.write(65);
byte[] bytes = {66, 67, 68};
os.write(bytes, 1, 2);
os.write("你好，世界".getBytes(StandardCharsets.UTF_8));
os.close();
InputStream is = new FileInputStream("E:\\a.txt");
bytes = new byte[1024];
int len = is.read(bytes);
System.out.println("new String(bytes, 0, len) = " + new String(bytes, 0, len));
is.close();
}
}
字节输出流
方法:
常用子类:
字符流
package com.coder.com;
import java.io.*;
public class Demo02 {
public static void main(String[] args) throws IOException {
Writer writer = new FileWriter("E:\\b.txt");
writer.write("你好，世界，");
writer.append("你好，Java").append("你好，Golang");
writer.close();
Reader reader = new FileReader("E:\\b.txt");
char[] chars = new char[1024];
int len = reader.read(chars);
String s = new String(chars, 0, len);
System.out.println("content = " + s);
reader.close();
}
}
转换流
package com.coder.com;
import java.io.*;
public class Demo03 {
/**
* 转换流
* 字节流 装饰为 字符流 :使用装饰着设计模式
* @param args
*/
public static void main(String[] args) throws IOException {
FileInputStream fis = new FileInputStream("E:\\a.txt");
//param1 要转换的字节流
//param2 指定编码名称
InputStreamReader isr = new InputStreamReader(fis, "UTF-8");
char[] buffs = new char[1024];
int len = isr.read(buffs);
for (int i = 0; i < len; i++) {
System.out.print(buffs[i]);
}
isr.close();
fis.close();
}
}
打印流
package com.coder.com;
import java.io.IOException;
import java.io.PrintStream;
import java.io.PrintWriter;
public class Demo04 {
/**
* 打印流
* @param args
*/
public static void main(String[] args) throws IOException {
PrintStream ps = new PrintStream("E:\\c.txt");
ps.println("你好，世界");
ps.println("你好，Java");
ps.println("你好， Golang");
ps.close();
PrintWriter pw = new PrintWriter("E:\\c.txt");
pw.println("你好Vue");
pw.println("你好SpringBoot");
pw.close();
}
}
Properties
package com.coder.com;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Properties;
public class Demo05 {
public static void main(String[] args) throws IOException {
// Properties properties = new Properties();
// properties.setProperty("name", "王令");
// properties.setProperty("age", "20");
// properties.setProperty("gender", "男");
// properties.store(new FileWriter("E:\\d.properties"), "个人信息");
Properties properties = new Properties();
properties.load(new FileReader("E:\\d.properties"));
System.out.println("name = " + properties.getProperty("name"));
System.out.println("age = " + properties.getProperty("age"));
System.out.println("gender = " + properties.getProperty("gender"));
}
}
序列化 反 序列化
package com.coder.com;
import java.io.*;
import java.util.ArrayList;
import java.util.List;
public class Demo06 {
/**
* 序列化 反 序列化
*
* @param args
*/
public static void main(String[] args) throws IOException, ClassNotFoundException {
// Person wl = new Person("王令", 21, "男");
// ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("E:\\person"));
// oos.writeObject(wl);
// oos.close();
// ObjectInputStream ois = new ObjectInputStream(new FileInputStream("E:\\person"));
// Person wl = (Person) ois.readObject();
// System.out.println("wl = " + wl);
// ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("E:\\list_person"));
// List<Person> people = new ArrayList<>();
// people.add(new Person("张三", 20, "男"));
// people.add(new Person("李四", 21, "女"));
// people.add(new Person("王五", 22, "男"));
// oos.writeObject(people);
// oos.close();
ObjectInputStream ois = new ObjectInputStream(new FileInputStream("E:\\list_person"));
List<Person> people = (List<Person>) ois.readObject();
for (Person person : people) {
System.out.println(person);
}
}
}
class Person implements Serializable {
private String name;
private Integer age;
private String gender;
public Person() {
}
public Person(String name, Integer age, String gender) {
this.name = name;
this.age = age;
this.gender = gender;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
@Override
public String toString() {
return "Person{" +
"name=‘" + name + ‘\‘‘ +
", age=" + age +
", gender=‘" + gender + ‘\‘‘ +
‘}‘;
}
}
标签：append load port fileread tag 输入流 系统 通过 code
原文地址：https://www.cnblogs.com/circle-coder/p/15040492.html
