JAVA实验5 流.doc

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 static 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 if (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）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) 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 new 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(); readFileAndDirectory(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;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/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.Entry 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 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(); catch (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.split(:);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 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 String getName() return name;public void setName(String 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 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.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);while (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：);tmpStr = 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(tmpStr) break;if (exit.equalsIgnoreCase(tmpStr) showMenu();continue; else if (#3.equalsIgnoreCase(code) try if(datas.size() 0 )saveStudents(datas);elseSystem.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 students = readStudentDat(studentDat);if(students = null | students.size() = 0)System.err.println(暂无学生信息);showMenu();elseSystem.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elseSystem.err.println(无法识别的菜单);showMenu();public static List readStudentDat(String fileName) 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 = 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 file = new File(studentDat);if (!file.exists() file.createNewFile();BufferedWriter bw = new BufferedWriter(new FileWriter(file,true);StringBuffer sb = new StringBuffer();Student s = null;for (int i = 0; i students.size(); i+) s = students.get(i);sb.setLength(0);sb.append(s.getNumber() + # + s.getName() + #+ s.getCourseName() + # + s.getScore();bw.write(sb.toString();bw.write(n);bw.flush();bw.close();public static void showMenu() System.out.println(-);System.out.println(-#1、录入学生信息-);System.out.println(-#2、查看学生信息-);System.out.println(-#3、保存学生信息-);System.out.println(-#4、退出-);System.out.println(-);5. 编写程序，在控制台窗口提示输入两个整数，然后接收这两个整数，并输出它们的和。（要求：键盘输入通过流封装System.in获取，不要使用Scanner类）InputStreamTest.javapackage com.ly.stream;import java.io.BufferedReader;import java.io.InputStreamReader;public class InputStreamTest public static void main(String args) BufferedReader in = new BufferedReader(new InputStreamReader(System.in); String line=null; try System.out.print(请输入第一个正整数a：); line = in.readLine(); int a = Integer.parseInt(line); System.out.print(请输入第二个正整数b：); line = in.readLine(); int b = Integer.parseInt(line); System.out.println(a+b= + String.valueOf(a+b); catch(Exception e) System.out.println(输入错误！); System.exit(0); 6.设计学生类Student，属性：编号（整型）；姓名（字符串），成绩（整型）。编写一个程序：要求：（1）输入3个学生的姓名和成绩，将其姓名和成绩保存到data.txt中；（2）然后从该文件中读取数据，求得这五个学生的平均成绩。Student.javapackage com.ly.file;public class Student int id; String name; int score; Student() public void setId(int id) this.id = id; public void setName(String name) = name; public void setScore(int score) this.score = score; public String toString() return this.id + t + + t + this.score + n; Main.javapackage com.ly.file;import java.io.BufferedReader;import java.io.DataInputStream;import java.io.DataOutputStream;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import