学步园

import java.io.*;<br /> import java.util.*;</p> <p>public class Test6_Map {<br /> public static void main(String[] args) {<br /> MyMapStu mms = new MyMapStu(new File("exp.txt"));<br /> System.out.println("请输入要查找内容的学号！");<br /> Scanner sc = new Scanner(System.in);<br /> long sno = sc.nextLong();<br /> Student stu2 = new Student(sno, " ");<br /> if(mms.containsKey(stu2)) {<br /> System.out.println("The name is "+mms.get(stu2.getNo()));</p> <p> } else {<br /> System.out.println("No such person!");<br /> }<br /> }<br /> }</p> <p>class Student { //简单定义学生类<br /> private Long sno;<br /> private String sname;</p> <p> public Student() {<br /> }<br /> public Student(Long sno, String sname) {<br /> this.sno = sno;<br /> this.sname = sname;<br /> }</p> <p> public Long getNo() {<br /> return sno;<br /> }<br /> public String getName() {<br /> return sname;<br /> }</p> <p>}</p> <p>class MyMapStu { //定义此类主要是为了与文件连接，从中把数据读到map中。<br /> Map<Long, String> map;</p> <p> public MyMapStu(File stuInfo) {<br /> if(!stuInfo.exists()) {<br /> try {<br /> stuInfo.createNewFile();<br /> System.out.println("请建一个拥有30名学生学生信息表！");<br /> BufferedWriter fos = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(stuInfo)));<br /> byte[] bytes = new byte[40];<br /> for(int i=0; i<30; i++) {<br /> BufferedReader br = new BufferedReader(new InputStreamReader(System.in));<br /> String str = new String();<br /> str = br.readLine();<br /> fos.write(str, 0, str.length());<br /> fos.newLine();<br /> }<br /> fos.close();<br /> } catch(IOException e) {<br /> e.printStackTrace();<br /> }<br /> }</p> <p> try {<br /> map = new HashMap<Long, String>();<br /> BufferedReader fis = new BufferedReader(new InputStreamReader(new FileInputStream(stuInfo)));<br /> String stmp;<br /> while((stmp = fis.readLine())!=null) {<br /> System.out.println(stmp);<br /> String[] sArray = stmp.split(" ");<br /> Student stu = new Student(Long.parseLong(sArray[0]), sArray[1]);<br /> map.put(stu.getNo(), stu.getName());<br /> }<br /> fis.close();<br /> System.out.println(map);<br /> } catch(IOException e) {<br /> e.printStackTrace();<br /> }<br /> }</p> <p> public boolean containsKey(Student stu) {<br /> if(map.containsKey(stu.getNo())) {<br /> return true;<br /> } else {<br /> return false;<br /> }<br /> }</p> <p> public String get(Long sno) {<br /> if(map.containsKey(sno)) {<br /> return map.get(sno);<br /> } else {<br /> return null;<br /> }<br /> } </p> <p>}