java基础第十二天

public class Demo2 {

public static void main(String[] args) {
// TODO Auto-generated method stub
/*
FileReader fr = null;
FileWriter fw = null;
try {
fr = new FileReader("c:/1.txt");
fw = new FileWriter("c:/2.txt");

char[] cbuf = new char[1024];

int ln;
while ( ( ln = fr.read(cbuf)) != -1) {

cbuf = String.valueOf(cbuf, 0, ln).toCharArray();
fw.write(cbuf);

}

} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {

try {
fr.close();
fw.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
*/

/*
HashMap<Integer, HashMap<Integer, HashSet<Integer>>> gen = new HashMap<Integer, HashMap<Integer, HashSet<Integer>>>();
int i = 1;
while (i < 7) {
int b = 1;
HashMap<Integer, HashSet<Integer>> cls = null;
while (b < 11) {
int c = 1;
cls = new HashMap<Integer, HashSet<Integer>>();
HashSet<Integer> na = new HashSet<Integer>();
while (c < 51) {

na.add(c);
c++;
}

cls.put(b, na);
b++;
}

gen.put(i, cls);
i++;

}
// HashMap<Integer, HashMap<Integer, HashSet<Integer>>>

for (Integer integer : gen.keySet()) {

HashMap<Integer, HashSet<Integer>> hs = gen.get(integer);

for (Entry<Integer, HashSet<Integer>> tt : hs.entrySet()) {
StringBuffer bu = new StringBuffer();
for (Integer integer2 : tt.getValue()) {
bu.append("第 " + integer2 + " 人 ");
}
System.out.println(integer +"年级 "+tt.getKey() + "班 " + "第 "+ bu + "\n");
}
}
*/