在java中怎样让用户输入文件名来打开一个文件？

import java.io.BufferedReader

import java.io.FileReader

import java.io.IOException

import java.util.Scanner

public class Test{

public static void main(String[] args) throws IOException {

Scanner sc = new Scanner(System.in)

System.out.println("请输入文件名:")

String fileName = sc.nextLine()

BufferedReader br = new BufferedReader(new FileReader(fileName))

String line

while((line = br.readLine()) != null){

System.out.println(line)

}

br.close()

sc.close()

}

}

输入:e:/1.txt

就会打开e盘下的1.txt了

给你一段文件 *** 作的例子

package com.file.sample

import java.io.*

public class FileOperate {

public FileOperate() {

}

/**

* 新建目录

*

* @param folderPath

* String 如 c:/fqf

* @return boolean

*/

public void newFolder(String folderPath) {

try {

String filePath = folderPath

filePath = filePath.toString()

java.io.File myFilePath = new java.io.File(filePath)

if (!myFilePath.exists()) {

myFilePath.mkdir()

}

} catch (Exception e) {

System.out.println("新建目录 *** 作出错")

e.printStackTrace()

}

}

/**

* 新建文件

*

* @param filePathAndName

* String 文件路径及名称 如c:/fqf.txt

* @param fileContent

* String 文件内容

* @return boolean

*/

public void newFile(String filePathAndName, String fileContent) {

try {

String filePath = filePathAndName

filePath = filePath.toString()

File myFilePath = new File(filePath)

if (!myFilePath.exists()) {

myFilePath.createNewFile()

}

FileWriter resultFile = new FileWriter(myFilePath)

PrintWriter myFile = new PrintWriter(resultFile)

String strContent = fileContent

myFile.println(strContent)

resultFile.close()

} catch (Exception e) {

System.out.println("新建目录 *** 作出错")

e.printStackTrace()

}

}

/**

* 删除文件

*

* @param filePathAndName

* String 文件路径及名称 如c:/fqf.txt

* @param fileContent

* String

* @return boolean

*/

public 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 *** 作出错")

e.printStackTrace()

}

}

/**

* 删除文件夹

*

* @param filePathAndName

* String 文件夹路径及名称 如c:/fqf

* @param fileContent

* String

* @return boolean

*/

public void delFolder(String folderPath) {

try {

delAllFile(folderPath)// 删除完里面所有内容

String filePath = folderPath

filePath = filePath.toString()

java.io.File myFilePath = new java.io.File(filePath)

myFilePath.delete()// 删除空文件夹

} catch (Exception e) {

System.out.println("删除文件夹 *** 作出错")

e.printStackTrace()

}

}

/**

* 删除文件夹里面的所有文件

*

* @param path

* String 文件夹路径 如 c:/fqf

*/

public void delAllFile(String path) {

File file = new File(path)

if (!file.exists()) {

return

}

if (!file.isDirectory()) {

return

}

String[] tempList = file.list()

File temp = null

for (int i = 0i <tempList.lengthi++) {

if (path.endsWith(File.separator)) {

temp = new File(path + tempList[i])

} else {

temp = new File(path + File.separator + tempList[i])

}

if (temp.isFile()) {

temp.delete()

}

if (temp.isDirectory()) {

delAllFile(path + "/" + tempList[i])// 先删除文件夹里面的文件

delFolder(path + "/" + tempList[i])// 再删除空文件夹

}

}

}

/**

* 复制单个文件

*

* @param oldPath

* String 原文件路径 如：c:/fqf.txt

* @param newPath

* String 复制后路径 如：f:/fqf.txt

* @return boolean

*/

public void copyFile(String oldPath, String newPath) {

try {

int bytesum = 0

int byteread = 0

File oldfile = new File(oldPath)

if (oldfile.exists()) { // 文件存在时

InputStream inStream = new FileInputStream(oldPath)// 读入原文件

FileOutputStream fs = new FileOutputStream(newPath)

byte[] buffer = new byte[1444]

int length

while ((byteread = inStream.read(buffer)) != -1) {

bytesum += byteread// 字节数 文件大小

System.out.println(bytesum)

fs.write(buffer, 0, byteread)

}

inStream.close()

}

} catch (Exception e) {

System.out.println("复制单个文件 *** 作出错")

e.printStackTrace()

}

}

/**

* 复制整个文件夹内容

*

* @param oldPath

* String 原文件路径 如：c:/fqf

* @param newPath

* String 复制后路径 如：f:/fqf/ff

* @return boolean

*/

public void copyFolder(String oldPath, String newPath) {

try {

(new File(newPath)).mkdirs()// 如果文件夹不存在 则建立新文件夹

File a = new File(oldPath)

String[] file = a.list()

File temp = null

for (int i = 0i <file.lengthi++) {

if (oldPath.endsWith(File.separator)) {

temp = new File(oldPath + file[i])

} else {

temp = new File(oldPath + File.separator + file[i])

}

if (temp.isFile()) {

FileInputStream input = new FileInputStream(temp)

FileOutputStream output = new FileOutputStream(newPath

+ "/" + (temp.getName()).toString())

byte[] b = new byte[1024 * 5]

int len

while ((len = input.read(b)) != -1) {

output.write(b, 0, len)

}

output.flush()

output.close()

input.close()

}

if (temp.isDirectory()) {// 如果是子文件夹

copyFolder(oldPath + "/" + file[i], newPath + "/" + file[i])

}

}

} catch (Exception e) {

System.out.println("复制整个文件夹内容 *** 作出错")

e.printStackTrace()

}

}

/**

* 移动文件到指定目录

*

* @param oldPath

* String 如：c:/fqf.txt

* @param newPath

* String 如：d:/fqf.txt

*/

public void moveFile(String oldPath, String newPath) {

copyFile(oldPath, newPath)

delFile(oldPath)

}

/**

* 移动文件到指定目录

*

* @param oldPath

* String 如：c:/fqf.txt

* @param newPath

* String 如：d:/fqf.txt

*/

public void moveFolder(String oldPath, String newPath) {

copyFolder(oldPath, newPath)

delFolder(oldPath)

}

public static void main(String[] args){

FileOperate filedemo=new FileOperate()

filedemo.delAllFile("d:/test")

}

}

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