ad5081d3
 孙向锦
初始化项目
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package com.fh.util;
import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.FileChannel.MapMode;
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ad5081d3
孙向锦
初始化项目
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public class FileUtil {
/**获取文件大小 返回 KB 保留3位小数 没有文件时返回0
* @param filepath 文件完整路径，包括文件名
* @return
*/
public static Double getFilesize(String filepath){
File backupath = new File(filepath);
return Double.valueOf(backupath.length())/1000.000;
}
/**
* 创建目录
* @param destDirName目标目录名
* @return
*/
public static Boolean createDir(String destDirName) {
File dir = new File(destDirName);
if(!dir.getParentFile().exists()){ //判断有没有父路径，就是判断文件整个路径是否存在
return dir.getParentFile().mkdirs(); //不存在就全部创建
}
return false;
}
/**
* 删除文件
* @param filePathAndName
* String 文件路径及名称 如c:/fqf.txt
* @param fileContent
* String
* @return boolean
*/
public static void delFile(String filePathAndName) {
try {
String filePath = filePathAndName;
filePath = filePath.toString();
java.io.File myDelFile = new java.io.File(filePath);
myDelFile.delete();
} catch (Exception e) {
System.out.println("删除文件操作出错");
e.printStackTrace();
}
}
/**
* 读取到字节数组0
* @param filePath //路径
* @throws IOException
*/
public static byte[] getContent(String filePath) throws IOException {
File file = new File(filePath);
long fileSize = file.length();
if (fileSize > Integer.MAX_VALUE) {
System.out.println("file too big...");
return null;
}
FileInputStream fi = new FileInputStream(file);
byte[] buffer = new byte[(int) fileSize];
int offset = 0;
int numRead = 0;
while (offset < buffer.length
&& (numRead = fi.read(buffer, offset, buffer.length - offset)) >= 0) {
offset += numRead;
}
// 确保所有数据均被读取
if (offset != buffer.length) {
throw new IOException("Could not completely read file " + file.getName());
}
fi.close();
return buffer;
}
/**
* 读取到字节数组1
*
* @param filePath
* @return
* @throws IOException
*/
public static byte[] toByteArray(String filePath) throws IOException {
File f = new File(filePath);
if (!f.exists()) {
throw new FileNotFoundException(filePath);
}
ByteArrayOutputStream bos = new ByteArrayOutputStream((int) f.length());
BufferedInputStream in = null;
try {
in = new BufferedInputStream(new FileInputStream(f));
int buf_size = 1024;
byte[] buffer = new byte[buf_size];
int len = 0;
while (-1 != (len = in.read(buffer, 0, buf_size))) {
bos.write(buffer, 0, len);
}
return bos.toByteArray();
} catch (IOException e) {
e.printStackTrace();
throw e;
} finally {
try {
in.close();
} catch (IOException e) {
e.printStackTrace();
}
bos.close();
}
}
/**
* 读取到字节数组2
*
* @param filePath
* @return
* @throws IOException
*/
public static byte[] toByteArray2(String filePath) throws IOException {
File f = new File(filePath);
if (!f.exists()) {
throw new FileNotFoundException(filePath);
}
FileChannel channel = null;
FileInputStream fs = null;
try {
fs = new FileInputStream(f);
channel = fs.getChannel();
ByteBuffer byteBuffer = ByteBuffer.allocate((int) channel.size());
while ((channel.read(byteBuffer)) > 0) {
// do nothing
// System.out.println("reading");
}
return byteBuffer.array();
} catch (IOException e) {
e.printStackTrace();
throw e;
} finally {
try {
channel.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
fs.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
/**
* Mapped File way MappedByteBuffer 可以在处理大文件时，提升性能
*
* @param filename
* @return
* @throws IOException
*/
public static byte[] toByteArray3(String filePath) throws IOException {
FileChannel fc = null;
RandomAccessFile rf = null;
try {
rf = new RandomAccessFile(filePath, "r");
fc = rf.getChannel();
MappedByteBuffer byteBuffer = fc.map(MapMode.READ_ONLY, 0,
fc.size()).load();
//System.out.println(byteBuffer.isLoaded());
byte[] result = new byte[(int) fc.size()];
if (byteBuffer.remaining() > 0) {
// System.out.println("remain");
byteBuffer.get(result, 0, byteBuffer.remaining());
}
return result;
} catch (IOException e) {
e.printStackTrace();
throw e;
} finally {
try {
rf.close();
fc.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
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