版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/yuming226/article/details/84455295
1、获取文本数据进行自减操作并写入文件中
package zifu;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
public class Demo9_Test {
public static void main(String[] args) throws IOException {
BufferedReader br = new BufferedReader(new FileReader("11.txt"));
String line = br.readLine();
br.close();
int times = Integer.parseInt(line);
if (times > 0) {
System.out.println("您还有" + times-- + "次机会");
FileWriter fw = new FileWriter("11.txt");
fw.write(times + "");
fw.close();
} else {
System.out.println("您的试用次数已到，请购买正版");
}
}
}
2、统计字符出现的次数
package zifu;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.TreeMap;
public class Demo11_KeyValue {
public static void main(String[] args) throws IOException {
BufferedReader br = new BufferedReader(new FileReader("11.txt"));
TreeMap<Character,Integer> tm = new TreeMap<>();
int b;
while ((b = br.read()) != -1) {
char c = (char) b;
tm.put(c, !tm.containsKey(c) ? 1 : tm.get(c) + 1);
/*if (!tm.containsKey(c)) {
tm.put(c, 1);
} else {
tm.put(c, tm.get(c) + 1);
}*/
}
br.close();
BufferedWriter bw = new BufferedWriter(new FileWriter("copy.txt"));
//FileOutputStream bw = new FileOutputStream("copy.txt");
for (Character key : tm.keySet()) {
switch (key) {
case '\t':
bw.write("\\t" + "=" + tm.get(key));
break;
case '\n':
bw.write("\\n" + "=" + tm.get(key));
break;
case '\r':
bw.write("\\r" + "=" + tm.get(key));
break;
default:
break;
}
bw.write(key + "=" + tm.get(key));
bw.newLine();
}
bw.close();
}
}
运行结果如下：
