1、路径分隔符
package File_1;
import java.io.File;
public class PathDamo_1 {
public static void main(String[] args) {
String path = "C:\\";
System.out.println(path);
System.out.println(File.separatorChar);
System.out.println(File.separator);
path = "D:/";
System.out.println(path);
}
}
2、File对象的三种构建方式
package File_1;
import java.io.File;
public class FileDemo_2 {
public static void main(String[] args) {
String path = "F:/eclipse-workspace/Java300集_8/img.png";
File src1 = new File(path);
File src2 = new File(new File("F:/eclipse-workspace/Java300集_8/"),"img.png");
File src3 = new File("F:/eclipse-workspace/Java300集_8/img.png");
System.out.println(src1.length());
System.out.println(src2.length());
System.out.println(src3.length());
}
}
3、相对路径和绝对路径
package File_1;
import java.io.*;
public class FileDemo_3 {
public static void main(String[] args) {
File src = new File("F:/eclipse-workspace/Java300集_8/img.png");
System.out.println(src.getAbsolutePath());
src = new File("img.png");
System.out.println(src.getAbsolutePath());
src = new File("aa.png");
System.out.println(src.getAbsolutePath());
System.out.println(System.getProperty("user.dir"));
}
}
4、获取filde对象的路径和名称
package File_1;
import java.io.File;
public class FileDemo_4 {
public static void main(String[] args) {
File src = new File("img.png");
System.out.println("文件名:"+src.getName());
System.out.println("绝对路径:"+src.getAbsolutePath());
System.out.println("路径:"+src.getPath());
System.out.println("父路径:"+src.getParent());
System.out.println("父对象:"+src.getParentFile());
}
}
5、文件状态
package File_1;
import java.io.File;
public class FileDemo_5 {
public static void main(String[] args) {
File src = new File("img.png");
System.out.println("是否存在:"+src.exists());
System.out.println("是否文件:"+src.isFile());
System.out.println("是否文件夹:"+src.isDirectory());
System.out.println("是否绝对路径:"+src.isAbsolute());
System.out.println("是否隐藏:"+src.isHidden());
}
}
6、文件的创建和删除
package File_1;
import java.io.File;
import java.io.IOException;
public class FileDemo_6 {
public static void main(String[] args) {
File src = new File("a.txt");
try {
System.out.println(src.createNewFile());
System.out.println(File.createTempFile("bbb", ".tmp"));
} catch (IOException e) {
e.printStackTrace();
}
System.out.println(src.delete());
}
}
7、文件夹的创建
package File_1;
import java.io.File;
public class DirDemo_7 {
public static void main(String[] args) {
File src = new File("mkdir/test");
System.out.println(src.mkdir());
System.out.println(src.mkdirs());
}
}
8、查看下级目录
package File_1;
import java.io.File;
public class ListDemo_8 {
public static void main(String[] args) {
File src = new File("F:\\eclipse-workspace\\Java300集_8");
String[] dirs = src.list();
for (String d : dirs) {
System.out.println(d);
}
File[] files = src.listFiles();
for (File file : files) {
System.out.println(file.getAbsolutePath());
}
for(File file:src.listRoots()) {
System.out.println(file.getAbsolutePath());
}
}
}
9、编码——解码
package File_1;
import java.io.UnsupportedEncodingException;
public class CodeTest_11 {
public static void main(String[] args) throws UnsupportedEncodingException {
String msg = "壹贰叁贰壹";
byte[] datas = msg.getBytes();
System.out.println(datas.length);
datas = msg.getBytes("UTF-8");
System.out.println(datas.length);
msg = new String(datas,0,datas.length,"UTF-8");
System.out.println(msg);
}
}
10、