public class Test3{
public static void main(String[] args){
1.创建带缓冲的输入流对象
BufferedReader br = new BufferedReader (new FileReader("zzz.txt"));
2.创建双列集合对象TreeMap
TreeMap<Character,Integer> tm = new TreeMap<>();
3.将读到的字符存储在在双列集合中，存储的时候要做判断，如果不包含这个键，就将键和1存储，如果包含这个键，就将键和值加1存储
int ch;
while((ch = br.read()) != -1){
char c = (char)ch; //向下强制转型
if(!tm.containsKey(c)){
tm.put(c,1);
}else{
tm.put(c,tm.get(c)+1);
} [用三元运算符：tm.put(c,!tm.containsKey(c) ? 1 : tm.get(c)+1);]
}
4.关闭输入流
br.close();
5.创建输出流对象
BufferedWriter bw = new BufferedWriter (new FileWriter("times.txt"));
6.遍历集合将集合中的内容写到times.txt中
for(Character key : tm.keySet()){
Switch(key) {
case ' ':
bw.write("\t" + "=" +tm.get(key));
break;
case ' ':
bw.write("\n" + "=" +tm.get(key));
break;
case ' ':
bw.write("\r" + "=" +tm.get(key));
break;
default:
bw.write(key + "=" + tm.get(key)); //写出键和值
break;
}
bw.newLine();
}
7.关闭输出流
bw.close();
}
}