用java讀取桌面上的文檔"abc.txt",程序怎么寫(xiě)？

給一個(gè)代碼你就知道了，代碼里面文件的路徑改成你電腦上的文件的路徑

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import?java.io.BufferedReader;

import?java.io.FileInputStream;

import?java.io.IOException;

import?java.io.InputStreamReader;

/**

*?file?IO流讀取并輸出文件

*?@author?Administrator

*

*/

public?class?FileIO?{

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

FileInputStream?fis?=?new?FileInputStream("src/day03/BrDemo.java");//?要讀的文件路徑

InputStreamReader?isr?=?new?InputStreamReader(fis);//?字符流

BufferedReader?br?=?new?BufferedReader(isr);?//?緩沖

String?line?=?null;

while?((line?=?br.readLine())?!=?null)?{//?字符不等于空

System.out.println(line);//?一行一行地輸出

}

br.close();//?關(guān)閉文件

}

}

java Scanner讀取文件

用Scanner讀取文件流，將會(huì)遍歷文件中的所有行——允許對(duì)每一行進(jìn)行處理，而不保持對(duì)它的引用。總之沒(méi)有把它們存放在內(nèi)存中，這是java提供的一種針對(duì)大文件進(jìn)行讀取的機(jī)制。

以下是示例代碼：

FileInputStream inputStream = null;

Scanner sc = null;

try {

inputStream = new FileInputStream(path);

sc = new Scanner(inputStream, "UTF-8");

while (sc.hasNextLine()) {

String line = sc.nextLine();

// System.out.println(line);

}

// note that Scanner suppresses exceptions

if (sc.ioException() != null) {

throw sc.ioException();

}

} finally {

if (inputStream != null) {

inputStream.close();

}

if (sc != null) {

sc.close();

}

}

怎么用java代碼讀取excel文件

本例使用java來(lái)讀取excel的內(nèi)容并展出出結(jié)果，代碼如下：

復(fù)制代碼 代碼如下:

import java.io.BufferedInputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.text.DecimalFormat;

import java.text.SimpleDateFormat;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Date;

import java.util.List;

import org.apache.poi.hssf.usermodel.HSSFCell;

import org.apache.poi.hssf.usermodel.HSSFDateUtil;

import org.apache.poi.hssf.usermodel.HSSFRow;

import org.apache.poi.hssf.usermodel.HSSFSheet;

import org.apache.poi.hssf.usermodel.HSSFWorkbook;

import org.apache.poi.poifs.filesystem.POIFSFileSystem;

public class ExcelOperate {

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

File file = new File("ExcelDemo.xls");

String[][] result = getData(file, 1);

int rowLength = result.length;

for(int i=0;irowLength;i++) {

for(int j=0;jresult[i].length;j++) {

System.out.print(result[i][j]+"\t\t");

}

System.out.println();

}

}

/**

* 讀取Excel的內(nèi)容，第一維數(shù)組存儲(chǔ)的是一行中格列的值，二維數(shù)組存儲(chǔ)的是多少個(gè)行

* @param file 讀取數(shù)據(jù)的源Excel

* @param ignoreRows 讀取數(shù)據(jù)忽略的行數(shù)，比喻行頭不需要讀入 忽略的行數(shù)為1

* @return 讀出的Excel中數(shù)據(jù)的內(nèi)容

* @throws FileNotFoundException

* @throws IOException

*/

public static String[][] getData(File file, int ignoreRows)

throws FileNotFoundException, IOException {

ListString[] result = new ArrayListString[]();

int rowSize = 0;

BufferedInputStream in = new BufferedInputStream(new FileInputStream(

file));

// 打開(kāi)HSSFWorkbook

POIFSFileSystem fs = new POIFSFileSystem(in);

HSSFWorkbook wb = new HSSFWorkbook(fs);

HSSFCell cell = null;

for (int sheetIndex = 0; sheetIndex wb.getNumberOfSheets(); sheetIndex++) {

HSSFSheet st = wb.getSheetAt(sheetIndex);

// 第一行為標(biāo)題，不取

for (int rowIndex = ignoreRows; rowIndex = st.getLastRowNum(); rowIndex++) {

HSSFRow row = st.getRow(rowIndex);

if (row == null) {

continue;

}

int tempRowSize = row.getLastCellNum() + 1;

if (tempRowSize rowSize) {

rowSize = tempRowSize;

}

String[] values = new String[rowSize];

Arrays.fill(values, "");

boolean hasValue = false;

for (short columnIndex = 0; columnIndex = row.getLastCellNum(); columnIndex++) {

String value = "";

cell = row.getCell(columnIndex);

if (cell != null) {

// 注意：一定要設(shè)成這個(gè)，否則可能會(huì)出現(xiàn)亂碼

cell.setEncoding(HSSFCell.ENCODING_UTF_16);

switch (cell.getCellType()) {

case HSSFCell.CELL_TYPE_STRING:

value = cell.getStringCellValue();

break;

case HSSFCell.CELL_TYPE_NUMERIC:

if (HSSFDateUtil.isCellDateFormatted(cell)) {

Date date = cell.getDateCellValue();

if (date != null) {

value = new SimpleDateFormat("yyyy-MM-dd")

.format(date);

} else {

value = "";

}

} else {

value = new DecimalFormat("0").format(cell

.getNumericCellValue());

}

break;

case HSSFCell.CELL_TYPE_FORMULA:

// 導(dǎo)入時(shí)如果為公式生成的數(shù)據(jù)則無(wú)值

if (!cell.getStringCellValue().equals("")) {

value = cell.getStringCellValue();

} else {

value = cell.getNumericCellValue() + "";

}

break;

case HSSFCell.CELL_TYPE_BLANK:

break;

case HSSFCell.CELL_TYPE_ERROR:

value = "";

break;

case HSSFCell.CELL_TYPE_BOOLEAN:

value = (cell.getBooleanCellValue() == true ? "Y"

: "N");

break;

default:

value = "";

}

}

if (columnIndex == 0 value.trim().equals("")) {

break;

}

values[columnIndex] = rightTrim(value);

hasValue = true;

}

Java如何讀寫(xiě)txt文件的代碼

有關(guān)Java如何讀寫(xiě)txt文件這個(gè)問(wèn)題經(jīng)常在面試時(shí)會(huì)被問(wèn)到，不懂或不熟悉的同志們可是要記好了喲!先來(lái)看下具體實(shí)現(xiàn)吧! package common; import java.io.*; import java.util.ArrayList; public class IOTest { public static void main (String args[]) { ReadDate(); WriteDate(); } /** * 讀取數(shù)據(jù) */ public static void ReadDate() { String url = “e:/2.txt”; try { FileReader read = new FileReader(new File(url)); StringBuffer sb = new StringBuffer(); char ch[] = new char[1024]; int d = read.read(ch); while(d!=-1){ String str = new String(ch,0,d); sb.append(str); d = read.read(ch); } System.out.print(sb.toString()); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } /** * 寫(xiě)入數(shù)據(jù) */ public static void WriteDate() { try{ File file = new File(“D:/abc.txt”); if (file.exists()) { file.delete(); } file.createNewFile(); BufferedWriter output = new BufferedWriter(new FileWriter(file)); ArrayList ResolveList = new ArrayList(); for (int i = 0; i 10; i++) { ResolveList.add(Math.random()* 100); } for (int i=0 ;i output.write(String.valueOf(ResolveList.get(i)) + “\n”); } output.close(); } catch (Exception ex) { System.out.println(ex); } } }

JAVA 讀取文件

package file;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.InputStream;

public class ReadFile {

/**

* @param args

* @throws IOException

*/

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

// TODO Auto-generated method stub

//將一個(gè)已存在文件加載到內(nèi)存中,讀取文本文件

InputStream is = new FileInputStream("xxx.txt");

//獲得文件可讀取的字節(jié)數(shù)

int num = is.available();

System.out.println(num);

char[] cs = new char[num];

for (int i = 0; i num; i++) {

int num2 = is.read();//ashc碼

char c = (char)num2;//ashc轉(zhuǎn)換成字符

cs[i]=c;

}

String str = new String(cs);

System.out.println(str);

is.close();

}

}