Java 创建txt文件与读写内容
package com.broadtext.eim.test;import java.io.BufferedReader;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.FileReader;import java.io.FileWriter;import java.io.IOException;import java.io.InputStreamReader;import java.io.PrintWriter;/** * * TODO 此处为类的功能性说明 * @Time 下午06:28:41 * @author mengjiahao */public class WriteTextService {public static BufferedReader bufread;// 指定文件路径和名称private static String path = "D:/sessionId.txt";private static File filename = new File(path);private static String readStr = "";/** *//** * 创建文本文件. * * @throws IOException * */public static void creatTxtFile() throws IOException {if (!filename.exists()) {filename.createNewFile();System.err.println(filename + "已创建！");}}/** *//** * 读取文本文件. * * @throws IOException * */public static String readTxtFile() throws IOException {String strs = "";try {FileReader read = new FileReader(filename);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);}strs = sb.toString();} catch (FileNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();}System.out.println("文件内容是:" + "\r\n" + strs);return strs;}/** *//** * 写文件. * */public static void writeTxtFile(String newStr) throws IOException {// 创建文件creatTxtFile();// 读取文件String str = readTxtFile();// 写入文件FileWriter fw = new FileWriter(path);if (str.length() < 1) {fw.write(newStr);} else {fw.write(str + "\r\n" + newStr);}fw.close();}/** *//** * 将文件中指定内容的第一行替换为其它内容. * * @param oldStr * 查找内容 * @param replaceStr * 替换内容 */public static void replaceTxtByStr(String oldStr, String replaceStr) {String temp = "";try {File file = new File(path);FileInputStream fis = new FileInputStream(file);InputStreamReader isr = new InputStreamReader(fis);BufferedReader br = new BufferedReader(isr);StringBuffer buf = new StringBuffer();// 保存该行前面的内容for (int j = 1; (temp = br.readLine()) != null&& !temp.equals(oldStr); j++) {buf = buf.append(temp);buf = buf.append(System.getProperty("line.separator"));}// 将内容插入buf = buf.append(replaceStr);// 保存该行后面的内容while ((temp = br.readLine()) != null) {buf = buf.append(System.getProperty("line.separator"));buf = buf.append(temp);}br.close();FileOutputStream fos = new FileOutputStream(file);PrintWriter pw = new PrintWriter(fos);pw.write(buf.toString().toCharArray());pw.flush();pw.close();} catch (IOException e) {e.printStackTrace();}}/** *//** * main方法测试 * * @param s * @throws IOException */public static void main(String[] s) throws IOException {// 创建文件creatTxtFile();// 读取文件readTxtFile();// 写入文件writeTxtFile("道是无晴却有晴");// 读取文件readTxtFile();}}