Rhythmk 一步一步学 JAVA (19) JAVA IO 文件常用操作

package com.rhythmk.filedemo;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.text.DateFormat;
import java.text.FieldPosition;
import java.text.ParsePosition;
import java.text.SimpleDateFormat;
import java.util.Properties;
import java.util.UUID;

import org.junit.Test;

public class file_demo1 {

public String getPath() {
return System.getProperty("user.dir");
}

@Test
public void 获取系统路径() {
String path = System.getProperty("user.dir");
System.out.println(path);
}

@Test
public void 写入文件() throws IOException {
String filePath = getPath() + "\\a.txt";
File file = new File(filePath);

if (file.canWrite()) {
System.out.println("可写");
}
FileWriter writer = new FileWriter(file, true);

// 写入时间
SimpleDateFormat time = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
writer.write("-------" + time.format(new java.util.Date()) + "\r\n");
// 写入随机GUID
writer.write(UUID.randomUUID().toString() + "\r\n");
writer.flush();
writer.close();

System.out.println("写入文件成功路径：" + filePath);

}

@Test
public void 读取文件() throws IOException {

String filePath = getPath() + "\\a.txt";
BufferedReader reader = new BufferedReader(new InputStreamReader(
new FileInputStream(filePath), "UTF-8"));
String txt = null;
while ((txt = reader.readLine()) != null) {
System.out.println(txt);

}

}

@Test
public void 遍历文件夹() throws IOException {
String filePath = getPath() + "\\src";
ReadFile(filePath);

}

private void ReadFile(String path) throws IOException {
File file = new File(path);

if (file.isDirectory()) {
System.out.println("当前目录地址为:" + path + "\r\n");
File[] filelist = file.listFiles();
for (File f : filelist) {
ReadFile(f.getAbsolutePath());

}
} else {
System.out.println("------当前文件地址为:" + path + "\r\n");
BufferedReader reader = new BufferedReader(new InputStreamReader(
new FileInputStream(path), "UTF-8"));
String txt = null;
while ((txt = reader.readLine()) != null) {
System.out.println(txt);

}
}
}

@Test
public void 删除文件() {
String filePath = getPath() + "\\12.txt";
File file = new File(filePath);
file.deleteOnExit();
}

@Test
public void 获取文件信息() {
String filePath = getPath() + "\\a.txt";
File file = new File(filePath);
System.out.println("是否可读(canRead):" + file.canRead());
System.out.println("当前文件路径(getAbsolutePath):" + file.getAbsolutePath());
System.out.println("文件名称:" + file.getName());
System.out.println("文件大小:" + file.length());
System.out.println("文件是否存在:" + file.exists());
String fileNAME = file.getName();
System.out.println("后缀名:"
+ fileNAME.substring(fileNAME.lastIndexOf(".") + 1));
}

@Test
public void 重命名() {
String filePath = getPath() + "\\a.txt";
File file = new File(filePath);
File file2 = new File(getPath() + "\\aaa.txt");
file.renameTo(file2);

System.out.println("文件是否存在:" + file2.exists());

}

@Test
public void 读取属性文件() {
String filePath = getPath() + "\\src\\app.properties";
Properties pro = new Properties();
try {
InputStream input = new FileInputStream(new File(filePath));
pro.load(input);
input.close();
} catch (Exception e) {
// TODO: handle exception
}
System.out.println(pro.getProperty("rhythmk"));
}

}