JAVA实验5流.docx

1、JAVA实验5流实验5 流1. 编写程序，要求：用户在键盘每输入一行文本，程序将这段文本显示在控制台中。当用户输入的一行文本是“exit”（不区分大小写）时，程序将用户所有输入的文本都写入到文件log.txt中，并退出。（要求：控制台输入通过流封装System.in获取，不要使用Scanner）package shiyanwu1;import java.io.BufferedReader; import java.io.InputStreamReader; import java.io.PrintWriter; public class test1 / 获得系统换行符 private stat

2、ic final String LINE_SEP = System.getProperty(line.separator); public static void main(String args) throws Exception try (BufferedReader in = new BufferedReader( new InputStreamReader(System.in) String line; StringBuilder sBuilder = new StringBuilder(); while (true) line = in.readLine(); / 读入一行字符串 i

3、f (line = null | exit.equals(line)|EXIT.equals(line) break; sBuilder.append(line).append(LINE_SEP); / 将 sBuilder 中的数据写入 log.txt try (PrintWriter writer = new PrintWriter(D:/java examples/my java/src/shiyanwu1/show.txt) writer.print(sBuilder.toString(); 2. 查看File类的API文档，使用该类实现一个类FileList，它提供两个静态方法：1）

4、printContentsInOneDirectory：能够将输入参数path所指定的本地磁盘路径下的所有目录和文件的名称（指明是目录还是文件，格式见下图）打印出来；2）readFileAndDirectory：能够将输入参数path所指定的本地磁盘路径下的所有目录（包含子目录）和文件的名称（指明是目录还是文件，格式见下图）以层次化结构打印出来。例如，某个目录下面有子目录a和文件Teacher.class，目录a下面有子目录b（下面有文件Teacher.java）和c（下面有文件Test.java和Test.class）以及文件1.txt，将该目录对应的路径作为输入参数调用该方法，程序的输出如

5、下图所示。package shiyanwu2;import java.io.File; public class test2 Public static void printContentsInOneDirectory(String path) File file = new File(path); if (!file.exists() throw new RuntimeException(String.format(文件 %s 不存在！, path); File childFiles = file.listFiles(); for (File childFile : childFiles)

6、if (childFile.isFile() System.out.format(文件 %sn, childFile.getName(); else System.out.format(目录 %sn, childFile.getName(); /* * * param path 目录路径 * param indent 当前缩进（即输出 - ) 的个数 */ public static void readFileAndDirectory(String path, int indent) File file = new File(path); if (!file.exists() throw ne

7、w RuntimeException(String.format(文件 %s 不存在！, path); File childFiles = file.listFiles(); for (File childFile : childFiles) for (int i = 0; i indent; +i) System.out.print(-); if (childFile.isFile() System.out.format(文件 %sn, childFile.getName(); else System.out.format(目录 %sn, childFile.getName(); readF

8、ileAndDirectory(childFile.getAbsolutePath(), indent + 2); public static void main(String args) throws Exception System.out.println(测试 printContentsInOneDirectory 方法：); printContentsInOneDirectory(some_dir); System.out.println(n测试 readFileAndDirectory 方法：); readFileAndDirectory(some_dir, 0); 3. 假设某个餐

9、馆平时使用：1）文本文件（orders.txt）记录顾客的点菜信息，每桌顾客的点菜记录占一行。每行顾客点菜信息的记录格式是“菜名：数量，菜名：数量，菜名：数量”。例如：“烤鸭：1，土豆丝：2，烤鱼：1”。2）文本文件（dishes.txt）记录每种菜的具体价格，每种菜及其价格占一行，记录格式为“菜名：价格“。例如：“烤鸭：169”。编写一个程序，能够计算出orders.txt中所有顾客消费的总价格。package shiyanwu3;import java.io.BufferedReader;import java.io.File;import java.io.FileInputStream;

10、import java.io.InputStream;import java.io.InputStreamReader;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;public class order public static void main(String args) order first = new order(); List orderDatas = first.readFile(D:/java examples/my java/src/

11、shiyanwu3/orders.txt); List dishesDatas = first.readFile(D:/java examples/my java/src/shiyanwu3/dishes.txt); Map orderDetail = first.resolveOrderDatas(orderDatas); Map dishesDetail = firs .resolveOrderDatas(dishesDatas); String dishesName = null; int dishesCount = 0; int totalPrice = 0; for (Map.Ent

12、ry e : orderDetail.entrySet() dishesName = e.getKey(); dishesCount = e.getValue(); totalPrice += dishesDetail.get(dishesName) * dishesCount; System.err.println(dishesName+总消费为：+totalPrice); private List readFile(String fileName) if (fileName != null & !.equals(fileName) File file = null; file = new

13、File(fileName); if (file.exists() List datas = new ArrayList(); try InputStream is = new FileInputStream(file); BufferedReader br = new BufferedReader( new InputStreamReader(is,gb2312); String str = null; while (true) str = br.readLine(); if (str != null) datas.add(str); else break; br.close(); catc

14、h (Exception e) return datas; return null; private Map resolveOrderDatas(List datas) String temp1 = null, temp2 = null; String detailStr = null; Map orderDetail = new HashMap(); for (int i = 0; i datas.size(); i+) temp1 = datas.get(i).split(,); for (int j = 0; j temp1.length; j+) temp2 = temp1j.spli

15、t(:); if (temp2.length = 2) if (orderDetail.get(temp20) != null) orderDetail.put(temp20, Integer.parseInt(temp21) + orderDetail.get(temp20); else orderDetail.put(temp20, Integer.parseInt(temp21); return orderDetail; private Map resolveDishesDatas(List datas) Map dishesDetail = new HashMap(); String

16、temp = null; for (int i = 0; i datas.size(); i+) temp = datas.get(i).split(:); if (temp.length = 2) dishesDetail.put(temp0, Integer.parseInt(temp1); return dishesDetail; 4. 设计学生类Student，属性：学号（整型）；姓名（字符串），选修课程（名称）及课程成绩（整型）。编写一个控制台程序，能够实现Student信息的保存、读取。具体要求：（1）提供Student信息的保存功能：通过控制台输入若干个学生的学号、姓名以及每个学

17、生所修课程的课程名和成绩，将其信息保存到data.dat中；（2）数据读取显示：能够从data.dat文件中读取学生及其课程成绩并显示于控制台。package shiyanwu4;public class Student private int number; private String name; private String courseName; private int score; public int getNumber() return number; public void setNumber(int number) this.number = number; public S

18、tring getName() return name; public void setName(String name) this.name = name; public String getCourseName() return courseName; public void setCourseName(String courseName) this.courseName = courseName; public int getScore() return score; public void setScore(int score) this.score = score; package

19、shiyanwu4;import java.io.BufferedReader;import java.io.BufferedWriter;import java.io.File;import java.io.FileInputStream;import java.io.FileWriter;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.util.ArrayList;import java.util.List;import java.util.

20、Scanner;public class StudentMgr public static final String studentDat = E:/data.dat; public static void main(String args) showMenu(); Scanner s = null; s = new Scanner(System.in); String code = null; Student student; List datas = new ArrayList(); List savedStudents = readStudentDat(studentDat); whil

21、e (true) code = s.next(); if (#4.equalsIgnoreCase(code) System.err.println(程序已退出); break; else if (#1.equalsIgnoreCase(code) String tmpStr = null; int tmpInt; while (true) System.out.print(学生学号：); tmpInt = s.nextInt(); student = new Student(); student.setNumber(tmpInt); System.out.print(学生姓名：); tmpS

22、tr = s.next(); student.setName(tmpStr); System.out.print(学生课程：); tmpStr = s.next(); student.setCourseName(tmpStr); System.out.print(课程成绩：); tmpInt = s.nextInt(); student.setScore(tmpInt); datas.add(student); System.out.println(输入exit结束信息录入,输入其他继续录入); tmpStr = s.next(); if (exit.equalsIgnoreCase(tmpS

23、tr) break; if (exit.equalsIgnoreCase(tmpStr) showMenu(); continue; else if (#3.equalsIgnoreCase(code) try if(datas.size() 0 ) saveStudents(datas); else System.err.println(无可保存的学生信息); catch (IOException e) System.err.println(保存学生信息异常); e.printStackTrace(); else if (#2.equalsIgnoreCase(code) List stud

24、ents = readStudentDat(studentDat); if(students = null | students.size() = 0) System.err.println(暂无学生信息); showMenu(); else System.err.println(已有学生人数：+students.size(); for(int i=0;istudents.size();i+) /这里输出学生信息 else System.err.println(无法识别的菜单); showMenu(); public static List readStudentDat(String file

25、Name) if (fileName != null & !.equals(fileName) File file = null; file = new File(fileName); Student student = null; if (file.exists() List datas = new ArrayList(); try InputStream is = new FileInputStream(file); BufferedReader br = new BufferedReader( new InputStreamReader(is, gb2312); String str =

26、 null; String infos = null; while (true) str = br.readLine(); if (str != null) student = new Student(); str = br.readLine(); infos = str.split(#); student.setNumber(Integer.parseInt(infos0); student.setName(infos1); student.setCourseName(infos2); student.setScore(Integer.parseInt(infos3); datas.add(student); else break; br.close(); catch (Exception e) e.printStackTrace(); return datas; return null; public static void saveStudents(List students) throws IOException File