day17

fos.txt

@@ -0,0 +1 @@
+abcsdabc

fos_bak.txt

@@ -0,0 +1 @@
+abcsdabc

jdbc.properties

@@ -1 +1,2 @@
-user_name = admin;
+user_name = admin;
+pwd = 123456;

src/main/java/com/sf/javase/day17/T.java

@@ -0,0 +1,274 @@
+package com.sf.javase.day17;
+
+import com.sun.scenario.effect.impl.sw.sse.SSEBlend_SRC_OUTPeer;
+import org.junit.jupiter.api.Test;
+
+import java.io.*;
+import java.text.SimpleDateFormat;
+import java.util.*;
+
+/**
+ * file操作和IO流
+ */
+public class T {
+
+    /**
+     * file构造器操作 - 绝对路径
+     */
+    @Test
+    public void t1(){
+        String pathName = "D:\\aaa.txt";
+        File file = new File(pathName);
+//        System.out.println(file);
+//        new File("D:\\aaa\\bbb.txt");
+        //  获取文件的名称(带后缀)
+        System.out.println("file.getName()="+file.getName());
+        //  获取文件的路径（相对或绝对）
+        System.out.println("file.getPath()="+file.getPath());
+        //获取文件的父路径
+        System.out.println("file.getParent()="+file.getParent());
+        // 获取文件的绝对路径
+        System.out.println("file.getAbsolutePath() = "+file.getAbsolutePath());
+    }
+
+
+    /**
+     * 相对路径
+     */
+    @Test
+    public void t2(){
+        File file = new File("jdbc.properties");
+        //  获取文件的名称(带后缀)
+        System.out.println("file.getName()="+file.getName());
+        //  获取文件的路径（相对或绝对）
+        System.out.println("file.getPath()="+file.getPath());
+        //获取文件的父路径
+        System.out.println("file.getParent()="+file.getParent());
+        //  System.getProperty("user.dir")   = 当前项目的根目录
+        System.out.println("System.getProperty(\"user.dir\") = "+System.getProperty("user.dir"));
+        // 路径分隔符
+//        File.separator
+        // 相对路径 获取文件的绝对路径   file.getAbsolutePath()  = System.getProperty("user.dir") + file.getPath()
+        System.out.println("file.getAbsolutePath() = "+file.getAbsolutePath());
+        //  区别  返回值不同
+        System.out.println("file.getAbsoluteFile() = "+file.getAbsoluteFile());
+        //  获取文件的长度  ---字节数  18
+        System.out.println("file.length() = "+file.length());
+        System.out.println("file.lastModified() = "+file.lastModified());
+//        long l = file.lastModified();
+//        Date date = new Date(l);
+//        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
+//        String format = simpleDateFormat.format(date);
+//        System.out.println(format);
+    }
+
+    @Test
+    public void t3(){
+        File file = new File("d:\\");
+        String[] list = file.list();    // 获取文件下的所有子文件或文件夹（的名字）
+        File[] files = file.listFiles();  // 获取文件下的所有子文件或文件夹（的路径）
+        for (File file1 : files) {
+            System.out.println(file1);
+        }
+//        for (String s : list) {
+//            System.out.println(s);
+//        }
+    }
+
+    /**
+     * file  - 重命名
+     */
+    @Test
+    public void t4() {
+        File file = new File("d:\\a.txt");
+        boolean b = file.renameTo(new File("d:\\b.txt"));
+        System.out.println(b);
+        //  ps：重命名不会更改修改时间
+        System.out.println(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date(new File("d:\\b.txt").lastModified())));
+        System.out.println(file.exists());
+        System.out.println(file.isDirectory());
+        System.out.println(file.isHidden());
+        System.out.println(file.canWrite());   ///文件是否为只写文件
+        System.out.println(file.canRead());   ///文件是否为只读文件
+
+        File file1 = new File("d:\\b.txt");
+        System.out.println(file1.canWrite());   ///文件是否为可写文件
+        System.out.println(file1.canRead());   ///文件是否为可读文件
+    }
+
+    /**
+     * file   创建和删除
+     */
+    @Test
+    public void t5() throws IOException {
+        File file = new File("d:\\java.txt");
+        boolean newFile = file.createNewFile();
+        System.out.println(newFile);
+        File fileDir = new File("d:\\aaa");
+        boolean mkdir = fileDir.mkdir();
+        System.out.println(mkdir);
+
+        File fileDirs = new File("d:\\aaa\\bbb\\ccc");
+        boolean mkdirs = fileDirs.mkdirs();
+        System.out.println(mkdirs);
+        File fileDel = new File("d:\\aaa\\bbb\\ccc");
+        boolean delete = fileDel.delete();
+        System.out.println(delete);
+    }
+
+    @Test
+    public void t6() throws IOException {
+        File file = new File("d:\\aaa\\bbb\\a.txt");
+        boolean newFile = file.createNewFile();
+        System.out.println(newFile);
+    }
+
+    /**
+     * io操作
+     * @throws IOException
+     */
+    @Test
+    public void t7() throws IOException {
+        File file = new File("jdbc.properties");
+        FileReader fileReader = new FileReader(file);
+        int data;
+//        int count  =0;
+        while ((data = fileReader.read()) != -1){
+//            count++;
+            System.out.print((char) data);
+        }
+//        System.out.println(count);
+        fileReader.close();
+    }
+
+    @Test
+    public void t8()  {
+        File file = new File("jdbc.properties");
+        FileReader fileReader = null;
+        try {
+            fileReader = new FileReader(file);
+            int data;
+            while ((data = fileReader.read()) != -1){
+                System.out.print((char) data);
+            }
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }finally {
+            try {
+                fileReader.close();
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        }
+
+    }
+
+    /**
+     * char[]
+     */
+    @Test
+    public void t9() throws IOException{
+        File file = new File("jdbc.properties");
+        FileReader fileReader = new FileReader(file);
+        char[] chars = new char[7];
+        int data;   //  读入有效字符
+        while ((data = fileReader.read(chars)) != -1){
+//            System.out.println(Arrays.toString(chars));
+//            List<char[]> chars1 = Arrays.asList(chars);
+            String s = new String(chars,0,data);
+            System.out.println(s);
+//            chars1.clear();
+        }
+        fileReader.close();
+    }
+
+    //  写出文件
+    @Test
+    public void t10() throws IOException {
+        File file = new File("aa.txt");
+        FileWriter fw = new FileWriter(file,true);  // true  追加
+        //  写出数据
+        fw.write(97);
+        fw.write(134);
+        fw.write('c');
+        fw.write('f');
+        fw.write(30000);
+        fw.close();
+    }
+
+    @Test
+    public void t11() throws IOException {
+        File file = new File("f.txt");
+        FileWriter fileWriter = new FileWriter(file, true);
+//        fileWriter.write("abcdef".toCharArray());
+//        fileWriter.write("abcdef".toCharArray(),0,4);
+//        fileWriter.write("abcdef");
+        fileWriter.write("abcdef",1,2);
+        fileWriter.close();
+    }
+
+    /**
+     * 字节输入流 FileInputStream
+     * @throws IOException
+     */
+    @Test
+    public void t12() throws IOException {
+        File file = new File("jdbc.properties");
+        FileInputStream fis = new FileInputStream(file);
+        // 开始读取数据
+        int data;
+        while ((data = fis.read()) != -1){
+            System.out.print((char) data);
+        }
+        fis.close();
+    }
+
+    @Test
+    public void t13() throws IOException {
+//        File file = new File("jdbc.properties");
+        FileInputStream fis = new FileInputStream("jdbc.properties");
+        int data;
+        byte[] bytes = new byte[1024];    // 将数据承装在bytes中
+        while ((data=fis.read(bytes)) != -1){
+//            System.out.println(Arrays.toString(bytes));
+            String str = new String(bytes, 0, data);
+            System.out.println(str);
+        }
+        fis.close();
+    }
+
+    @Test
+    public void t14() throws IOException {
+        FileOutputStream fos = new FileOutputStream("fos.txt");
+        fos.write(101);
+        fos.write(102);
+        fos.write(103);
+        fos.close();
+    }
+
+    @Test
+    public void t15() throws IOException {
+        FileOutputStream fos = new FileOutputStream("fos.txt",true);
+        fos.write("abcsd".getBytes(),0,3);
+        fos.close();
+    }
+
+
+    /**
+     * 实现复制
+     * @throws IOException
+     */
+    @Test
+    public void t16() throws IOException {
+        FileInputStream fis = new FileInputStream("fos.txt");
+        FileOutputStream fos = new FileOutputStream("fos_bak.txt");
+        byte[] bytes = new byte[1024];
+        int data;
+        while ((data = fis.read(bytes)) != -1){
+            fos.write(bytes,0,data);
+        }
+        System.out.println("success~");
+        fis.close();
+        fos.close();
+    }
+}