论坛上的一道入学测试题 - 黑马程序员技术交流社区

package reviewCode2;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
/**
* 把当前文件中的所有文本拷贝，存入一个txt文件，统计每个字符出现的次数并输出
*@author
*/
public class IOTest {
public static void main(String[] args) throws IOException {
File socfile = new File("G:\\BaiduYunDownload\\JavaEE\\MyWork\\reviewCode\\src\\reviewCode");
File destfile = new File("G:\\BaiduYunDownload\\JavaEE\\MyWork\\reviewCode\\src\\reviewCode2\\my.txt");
Myread(socfile,destfile);
}
public static void Myread(File socfile,File destfile) {
List<File> list = new ArrayList<File>();
if(!socfile.exists()){
throw new RuntimeException("非法路径");
}else if(!socfile.isDirectory()){
throw new RuntimeException("非法目录");
}
//获取目标目录集合
findFile(socfile,list);
FileReader fr = null;
FileWriter fw = null;
//将每一个字符放到map集合
Map map = new TreeMap();
try {
//将目录下的所有文件复制到同一个txt文件下
for (Iterator<File> it = list.iterator(); it.hasNext();) {
File file = it.next();
fr = new FileReader(file);
fw = new FileWriter(destfile,true);
int ch = 0;
while ((ch = fr.read()) != -1) {
if(map.get((char)ch)==null){
map.put((char)ch,1);
}else{
int i = (int)map.get((char)ch);
map.put((char)ch,++i);
}
fw.write(ch);
fw.flush();
}
}
//统计字符出现的次数
Set<Map.Entry<?,?>> set = map.entrySet();
for(Map.Entry<?,?> me:set){
System.out.println(me.getKey()+":"+me.getValue()+"次");
}
} catch (Exception e) {
System.out.println("复制文件发生错误");
}finally{
if(fr!=null){
try {
fr.close();
} catch (IOException e) {
throw new RuntimeException("关闭资源异常");
}
}
if(fw!=null){
try {
fw.close();
} catch (IOException e) {
throw new RuntimeException("关闭资源异常");
}
}
}
}
//查找目录下的所有文件
public static void findFile(File socfile,List<File> list) {
File[] files = socfile.listFiles();
for(File f:files){
if(f.isDirectory()){
findFile(f,list);
}else{
list.add(f);
}
}
}
}

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public static void main(String[] args)throws IOException
{
String dest = "E:\\MyEclipse 10\\heima\\src\\FileCharacterCount.java";
TreeMap<Character,Integer> map = new TreeMap<Character,Integer>();
BufferedReader br = new BufferedReader(new FileReader(dest));
String total = null;
String line = null;
while((line = br.readLine())!=null)
total = total+line;
br.close();
char[] arr = total.toCharArray();
for(Character c : arr)
{
if(map.containsKey(c))
map.put(c, map.get(c)+1);
map.put(c, 1);
}
for(Entry<Character,Integer> entry : map.entrySet())
{
System.out.println(entry.getKey()+":"+entry.getValue()+"次");
}
}

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