java基础多线程练习题（1）

package com.wh.text; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStreamReader; import java.io.OutputStreamWriter; import java.io.UnsupportedEncodingException; public class textutil { /** * * 如何使用java去除掉字符串前面的空格 * */ public static String replaceTextFirstBlack(String s){ for(int i=0;i<s.length();i++){ if(s.charAt(i)!=' '){ s=s.substring(i,s.length()); break; } } return s; } /*** * 去除掉每一行中前面几个数字： 原来： 196 112<url>http://34567maven.aliyun.com/nexus/content/repositories/central/</url> 结果 ： 112<url>http://34567maven.aliyun.com/nexus/content/repositories/central/</url> * */ public static String removeTextFirstNum(String string){ //System.out.println(replaceTextFirstBlack(string)); String str=string.trim(); String newStr = str.replaceAll("^([0-9]+)(\\s?)", ""); //^([0-9]+)(\\s?)$ //System.out.println(string.trim()); System.out.println(newStr); return newStr; } public static File removeFileTextFirstNum(File InputFile,File OutputFile) throws UnsupportedEncodingException, FileNotFoundException{ //File f=new File("d:/res.txt"); try { FileInputStream fis=new FileInputStream(InputFile); InputStreamReader isr=new InputStreamReader(fis, "UTF-8"); BufferedReader br = new BufferedReader(isr); //写入中文字符时解决中文乱码问题 FileOutputStream fos=new FileOutputStream(OutputFile); OutputStreamWriter osw=new OutputStreamWriter(fos, "UTF-8"); BufferedWriter bw=new BufferedWriter(osw); //简写如下 //BufferedReader br = new BufferedReader(new InputStreamReader( // new FileInputStream("E:/1556.txt"), "UTF-8")); String line=""; // String[] arrs=null; while ((line=br.readLine())!=null) { // arrs=line.split(","); // System.out.println(arrs[0] + " : " + arrs[1] + " : " + arrs[2]); line=removeTextFirstNum(line); bw.write(line+"\t\n"); } //简写如下： //BufferedWriter writer = new BufferedWriter(new OutputStreamWriter( // new FileOutputStream(new File("E:/1556.txt")), "UTF-8")); // for(String arr:arrs){ // bw.write(arr+"\t\n"); // } br.close(); isr.close(); fis.close(); //注意关闭的先后顺序，先打开的后关闭，后打开的先关闭 bw.close(); osw.close(); fos.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); }finally { } return OutputFile; } public static void main(String[] args) { TextReplaceTextFirstBlack(); } private static void TextReplaceTextFirstBlack() { String string=" 196 112<url>http://34567maven.aliyun.com/nexus/content/repositories/central/</url>"; System.out.println(replaceTextFirstBlack(string)); String str=string.trim(); String newStr = str.replaceAll("^([0-9]+)(\\s?)", ""); //^([0-9]+)(\\s?)$ System.out.println(string.trim()); System.out.println(newStr); try { removeFileTextFirstNum(new File("C:/Users/Administrator/Desktop/copy"),new File("d:/res.txt")); } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }