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🔖 JAVA IO 示例
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‎codes/basics/src/main/java/io/github/dunwu/javase/io/InputStreamReaderDemo.java

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package io.github.dunwu.javase.io;
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import java.io.*;
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/**
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* 将 InputStream 转为 Reader
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* @author Zhang Peng
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*/
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public class InputStreamReaderDemo {
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public static void main(String args[]) throws IOException {
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File f = new File("d:" + File.separator + "test.txt");
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Reader reader = new InputStreamReader(new FileInputStream(f));
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char c[] = new char[1024];
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int len = reader.read(c);
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reader.close();
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System.out.println(new String(c, 0, len));
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}
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}

‎codes/basics/src/main/java/io/github/dunwu/javase/io/ObjectStream.java

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package io.github.dunwu.javase.io;
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import java.io.*;
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/**
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* 对象输入输出流，一般用于对象序列化
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* @author Zhang Peng
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*/
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public class ObjectStream {
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public static class Person implements Serializable {
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private String name;
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private int age;
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public Person(String name, int age) {
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this.name = name;
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this.age = age;
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}
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@Override
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public String toString() {
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return "姓名：" + this.name + "；年龄：" + this.age;
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}
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}
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public static void writeObject(String filepath, Object obj[]) throws Exception {
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// 1.使用 File 类绑定一个文件
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File f = new File(filepath);
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// 2.把 File 对象绑定到流对象上
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OutputStream out = new FileOutputStream(f);
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ObjectOutputStream oos = new ObjectOutputStream(out);
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// 3.进行读或写操作
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oos.writeObject(obj);
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// 4.关闭流
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oos.close();
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}
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public static Object[] readObject(String filepath) throws Exception {
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// 1.使用 File 类绑定一个文件
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File f = new File(filepath);
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// 2.把 File 对象绑定到流对象上
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InputStream input = new FileInputStream(f);
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ObjectInputStream ois = new ObjectInputStream(input);
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// 3.进行读或写操作
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Object[] objects = (Object[]) ois.readObject();
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// 4.关闭流
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ois.close();
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return objects;
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}
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public static void main(String args[]) throws Exception {
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final String filepath = "d:\\object.txt";
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Person per[] = {new Person("张三", 30), new Person("李四", 31), new Person("王五", 32)};
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writeObject(filepath, per);
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Object o[] = readObject(filepath);
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for (int i = 0; i < o.length; i++) {
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Person p = (Person) o[i];
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System.out.println(p);
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}
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}
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}

‎codes/basics/src/main/java/io/github/dunwu/javase/io/OutputStreamWriterDemo.java

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package io.github.dunwu.javase.io;
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import java.io.*;
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/**
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* 将 OutputStream 转为 Writer
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* @author Zhang Peng
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*/
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public class OutputStreamWriterDemo {
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public static void main(String args[]) throws IOException {
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File f = new File("d:" + File.separator + "test.txt");
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Writer out = new OutputStreamWriter(new FileOutputStream(f));
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out.write("hello world!!");
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out.close();
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}
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}

‎codes/basics/src/main/java/io/github/dunwu/javase/io/ReaderAndWriterDemo.java

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package io.github.dunwu.javase.io;
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import java.io.*;
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/**
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* Reader 和 Writer 示例
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* @author Zhang Peng
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*/
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public class ReaderAndWriterDemo {
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public static void output(String filepath) throws IOException {
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// 1.使用 File 类绑定一个文件
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File f = new File(filepath);
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// 2.把 File 对象绑定到流对象上
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Writer out = new FileWriter(f);
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// Writer out = new FileWriter(f, true); // 追加内容方式
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// 3.进行读或写操作
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String str = "Hello World!!!\r\n";
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out.write(str);
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// 4.关闭流
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// 字符流操作时使用了缓冲区，并在关闭字符流时会强制将缓冲区内容输出
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// 如果不关闭流，则缓冲区的内容是无法输出的
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// 如果想在不关闭流时，将缓冲区内容输出，可以使用 flush 强制清空缓冲区
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out.flush();
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out.close();
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}
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public static char[] input(String filepath) throws IOException {
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// 1.使用 File 类绑定一个文件
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File f = new File(filepath);
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// 2.把 File 对象绑定到流对象上
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Reader input = new FileReader(f);
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// 3.进行读或写操作
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int temp = 0; // 接收每一个内容
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int len = 0; // 读取内容
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char[] c = new char[1024];
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while ((temp = input.read()) != -1) {
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// 如果不是-1就表示还有内容，可以继续读取
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c[len] = (char) temp;
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len++;
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}
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System.out.println("文件字符数为：" + len);
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// 4.关闭流
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input.close();
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return c;
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}
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public static void main(String[] args) throws IOException {
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String filepath = "d:\\test.txt";
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output(filepath);
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System.out.println("内容为：" + new String(input(filepath)));
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}
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}

‎codes/basics/src/main/java/io/github/dunwu/javase/io/ZipStreamDemo.java

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package io.github.dunwu.javase.io;
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import java.io.*;
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import java.util.zip.ZipEntry;
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import java.util.zip.ZipFile;
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import java.util.zip.ZipInputStream;
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import java.util.zip.ZipOutputStream;
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/**
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* @author Zhang Peng
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*/
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public class ZipStreamDemo {
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public static final String ZIP_FILE_PATH = "d:\\zipdemo.zip";
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public static void demo01(String zipfilepath) throws IOException {
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File file = new File(zipfilepath);
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ZipFile zipFile = new ZipFile(file);
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ZipEntry entry = zipFile.getEntry("mldn.txt");
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System.out.println("压缩文件的名称：" + zipFile.getName());
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File outputFile = new File("d:" + File.separator + "mldn_unzip.txt");
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OutputStream out = new FileOutputStream(outputFile); // 实例化输出流
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InputStream input = zipFile.getInputStream(entry); // 得到一个压缩实体的输入流
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int temp = 0;
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while ((temp = input.read()) != -1) {
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out.write(temp);
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}
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input.close(); // 关闭输入流
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out.close(); // 关闭输出流
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}
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/**
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* 压缩一个文件
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*/
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public static void output1(String filepath, String zipfilepath) throws Exception {
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// 1.使用 File 类绑定一个文件
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// 定义要压缩的文件
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File file = new File(filepath);
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// 定义压缩文件名称
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File zipFile = new File(zipfilepath);
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// 2.把 File 对象绑定到流对象上
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InputStream input = new FileInputStream(file);
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ZipOutputStream zipOut = new ZipOutputStream(new FileOutputStream(zipFile));
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// 3.进行读或写操作
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zipOut.putNextEntry(new ZipEntry(file.getName()));
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zipOut.setComment("This is a zip file.");
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int temp = 0;
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while ((temp = input.read()) != -1) { // 读取内容
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zipOut.write(temp); // 压缩输出
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}
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// 4.关闭流
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input.close();
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zipOut.close();
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}
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/**
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* 读取实体为一个文件的压缩包
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*/
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public static void input1(String zipfilepath, String filepath) throws Exception {
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// 1.使用 File 类绑定一个文件
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File zipFile = new File(zipfilepath);
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// 2.把 File 对象绑定到流对象上
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ZipInputStream input = new ZipInputStream(new FileInputStream(zipFile));
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// 3.进行读或写操作
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ZipEntry entry = input.getNextEntry(); // 得到一个压缩实体
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System.out.println("压缩实体名称：" + entry.getName());
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// 4.关闭流
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input.close();
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}
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/**
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* 压缩一个目录
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*/
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public static void output2(String dirpath, String zipfilepath) throws Exception {
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// 1.使用 File 类绑定一个文件
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// 定义要压缩的文件夹
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File file = new File(dirpath);
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// 定义压缩文件名称
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File zipFile = new File(zipfilepath);
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// 2.把 File 对象绑定到流对象上
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ZipOutputStream zipOut = new ZipOutputStream(new FileOutputStream(zipFile));
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zipOut.setComment("This is zip folder.");
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// 3.进行读或写操作
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int temp = 0;
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if (file.isDirectory()) { // 判断是否是文件夹
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File lists[] = file.listFiles(); // 列出全部文件
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for (int i = 0; i < lists.length; i++) {
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InputStream input = new FileInputStream(lists[i]);
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// 设置ZipEntry对象
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zipOut.putNextEntry(new ZipEntry(file.getName() + File.separator + lists[i].getName()));
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while ((temp = input.read()) != -1) {
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zipOut.write(temp);
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}
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input.close();
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}
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}
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// 4.关闭流
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zipOut.close();
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}
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/**
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* 解压实体为一个目录的压缩包
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*/
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public static void input2(String zipfilepath, String dirpath) throws Exception {
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// 1.使用 File 类绑定一个文件
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File file = new File(zipfilepath);
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ZipFile zipFile = new ZipFile(file);
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// 2.把 File 对象绑定到流对象上
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ZipInputStream zis = new ZipInputStream(new FileInputStream(file));
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// 3.进行读或写操作
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ZipEntry entry = null;
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while ((entry = zis.getNextEntry()) != null) { // 得到一个压缩实体
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System.out.println("解压缩" + entry.getName() + "文件。");
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// 定义输出的文件路径
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File outFile = new File(dirpath + File.separator + entry.getName());
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if (!outFile.getParentFile().exists()) { // 如果输出文件夹不存在
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outFile.getParentFile().mkdirs(); // 创建文件夹
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}
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if (!outFile.exists()) { // 判断输出文件是否存在
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outFile.createNewFile(); // 创建文件
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}
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InputStream input = zipFile.getInputStream(entry); // 得到每一个实体的输入流
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OutputStream out = new FileOutputStream(outFile); // 实例化文件输出流
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int temp = 0;
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while ((temp = input.read()) != -1) {
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out.write(temp);
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}
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input.close(); // 关闭输入流
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out.close(); // 关闭输出流
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}
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// 4.关闭流
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zis.close();
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}
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public static void main(String[] args) throws Exception {
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final String filepath = "d:\\demo.txt";
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final String zipfilepath = "d:\\demo.zip";
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final String dirpath = "d:\\demo2";
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final String dirpath2 = "d:\\new";
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final String zipfilepath2 = "d:\\demo2.zip";
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// demo01(ZIP_FILE_PATH);
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output1(filepath, zipfilepath);
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input1(zipfilepath, filepath);
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output2(dirpath, zipfilepath2);
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input2(zipfilepath2, dirpath2);
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}
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}

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