JAVA實驗5 流

1、實驗5 流1. 編寫程序，要求：用戶在鍵盤每輸入一行文本，程序?qū)⑦@段文本顯示在控制臺中。當用戶輸入的一行文本是“exit”（不區(qū)分大小寫）時，程序?qū)⒂脩羲休斎氲奈谋径紝懭氲轿募og.txt中，并退出。（要求：控制臺輸入通過流封裝System.in獲取，不要使用Scanner）package shiyanwu1;import java.io.BufferedReader; import java.io.InputStreamReader; import java.io.PrintWriter; public class test1 / 獲得系統(tǒng)換行符 private static final

2、 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(); / 讀入一行字

3、符串 if (line = null | "exit".equals(line)|"EXIT".equals(line) break; sBuilder.append(line).append(LINE_SEP); / 將 sBuilder 中的數(shù)據(jù)寫入 log.txt try (PrintWriter writer = new PrintWriter("D:/java examples/my java/src/shiyanwu1/show.txt") writer.print(sBuilder.toString(); 2. 查看Fi

4、le類的API文檔，使用該類實現(xiàn)一個類FileList，它提供兩個靜態(tài)方法：1）printContentsInOneDirectory：能夠?qū)⑤斎雲(yún)?shù)path所指定的本地磁盤路徑下的所有目錄和文件的名稱（指明是目錄還是文件，格式見下圖）打印出來；2）readFileAndDirectory：能夠?qū)⑤斎雲(yún)?shù)path所指定的本地磁盤路徑下的所有目錄（包含子目錄）和文件的名稱（指明是目錄還是文件，格式見下圖）以層次化結構打印出來。例如，某個目錄下面有子目錄a和文件Teacher.class，目錄a下面有子目錄b（下面有文件Teacher.java）和c（下面有文件Test.java和Test.cla

5、ss）以及文件1.txt，將該目錄對應的路徑作為輸入?yún)?shù)調(diào)用該方法，程序的輸出如下圖所示。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 =

6、file.listFiles(); for (File childFile : childFiles) if (childFile.isFile() System.out.format("文件 %sn", childFile.getName(); else System.out.format("目錄 %sn", childFile.getName(); /* * * param path 目錄路徑 * param indent 當前縮進（即輸出 - ) 的個數(shù) */ public static void readFileAndDirectory(Stri

7、ng 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()

8、 System.out.format("文件 %sn", childFile.getName(); else System.out.format("目錄 %sn", childFile.getName(); readFileAndDirectory(childFile.getAbsolutePath(), indent + 2); public static void main(String args) throws Exception System.out.println("測試 printContentsInOneDirectory 方法：

9、"); printContentsInOneDirectory("some_dir"); System.out.println("n測試 readFileAndDirectory 方法："); readFileAndDirectory("some_dir", 0); 3. 假設某個餐館平時使用：1）文本文件（orders.txt）記錄顧客的點菜信息，每桌顧客的點菜記錄占一行。每行顧客點菜信息的記錄格式是“菜名：數(shù)量，菜名：數(shù)量，菜名：數(shù)量”。例如：“烤鴨：1，土豆絲：2，烤魚：1”。2）文本文件（dishes.txt）記錄每

10、種菜的具體價格，每種菜及其價格占一行，記錄格式為“菜名：價格“。例如：“烤鴨：169”。編寫一個程序，能夠計算出orders.txt中所有顧客消費的總價格。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

11、.util.List;import java.util.Map;public class order public static void main(String args) order first = new order();List<String> orderDatas = first.readFile("D:/java examples/my java/src/shiyanwu3/orders.txt");List<String> dishesDatas = first.readFile("D:/java examples/my ja

12、va/src/shiyanwu3/dishes.txt");Map<String, Integer> orderDetail = first.resolveOrderDatas(orderDatas);Map<String, Integer> dishesDetail = firs.resolveOrderDatas(dishesDatas);String dishesName = null;int dishesCount = 0;int totalPrice = 0;for (Map.Entry<String, Integer> e : orde

13、rDetail.entrySet() dishesName = e.getKey();dishesCount = e.getValue();totalPrice += dishesDetail.get(dishesName) * dishesCount;System.err.println(dishesName+"總消費為："+totalPrice);private List<String> readFile(String fileName) if (fileName != null && !"".equals(fileNam

14、e) File file = null;file = new File(fileName);if (file.exists() List<String> datas = new ArrayList<String>();try InputStream is = new FileInputStream(file);BufferedReader br = new BufferedReader(new InputStreamReader(is,"gb2312");String str = null;while (true) str = br.readLine

15、();if (str != null) datas.add(str); else break;br.close(); catch (Exception e) return datas;return null;private Map<String, Integer> resolveOrderDatas(List<String> datas) String temp1 = null, temp2 = null;String detailStr = null;Map<String, Integer> orderDetail = new HashMap<>

16、;();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); el

17、se orderDetail.put(temp20, Integer.parseInt(temp21);return orderDetail;private Map<String, Integer> resolveDishesDatas(List<String> datas) Map<String, Integer> dishesDetail = new HashMap<>();String temp = null;for (int i = 0; i < datas.size(); i+) temp = datas.get(i).split

18、(":");if (temp.length = 2) dishesDetail.put(temp0, Integer.parseInt(temp1);return dishesDetail;4. 設計學生類Student，屬性：學號（整型）；姓名（字符串），選修課程（名稱）及課程成績（整型）。編寫一個控制臺程序，能夠?qū)崿F(xiàn)Student信息的保存、讀取。具體要求：（1）提供Student信息的保存功能：通過控制臺輸入若干個學生的學號、姓名以及每個學生所修課程的課程名和成績，將其信息保存到data.dat中；（2）數(shù)據(jù)讀取顯示：能夠從data.dat文件中讀取學生及其課程成績并

19、顯示于控制臺。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)

20、= 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

21、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 = "

22、;E:/data.dat"public static void main(String args) showMenu();Scanner s = null;s = new Scanner(System.in);String code = null;Student student;List<Student> datas = new ArrayList<Student>();List<Student> savedStudents = readStudentDat(studentDat);while (true) code = s.next();if (

23、"#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("學生學號：");tmpInt = s.nextInt();student = new Student();student.setNumber(tmpInt);System.out.print(&

24、quot;學生姓名：");tmpStr = s.next();student.setName(tmpStr);System.out.print("學生課程：");tmpStr = s.next();student.setCourseName(tmpStr);System.out.print("課程成績：");tmpInt = s.nextInt();student.setScore(tmpInt);datas.add(student);System.out.println("輸入exit結束信息錄入,輸入其他繼續(xù)錄入");t

25、mpStr = 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("無可保存的學生信息"); catch (IOException e) S

26、ystem.err.println("保存學生信息異常");e.printStackTrace();else if ("#2".equalsIgnoreCase(code) List<Student> students = readStudentDat(studentDat);if(students = null | students.size() = 0)System.err.println("暫無學生信息");showMenu();elseSystem.err.println("已有學生人數(shù)："+s

27、tudents.size();for(int i=0;i<students.size();i+)/這里輸出學生信息elseSystem.err.println("無法識別的菜單");showMenu();public static List<Student> readStudentDat(String fileName) if (fileName != null && !"".equals(fileName) File file = null;file = new File(fileName);Student stude

28、nt = null;if (file.exists() List<Student> datas = new ArrayList<Student>();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 !=

29、 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.printStackTr

30、ace();return datas;return null;public static void saveStudents(List<Student> 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 = n

31、ull;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

32、() System.out.println("-");System.out.println("-#1、錄入學生信息-");System.out.println("-#2、查看學生信息-");System.out.println("-#3、保存學生信息-");System.out.println("-#4、退出-");System.out.println("-");5.  編寫程序，在控制臺窗口提示輸入兩個整數(shù)，然后接收這兩個整數(shù)，并輸出它們的和。（要求：鍵盤輸入通過

33、流封裝System.in獲取，不要使用Scanner類）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

34、.out.print("請輸入第一個正整數(shù)a："); line = in.readLine(); int a = Integer.parseInt(line); System.out.print("請輸入第二個正整數(shù)b："); line = in.readLine(); int b = Integer.parseInt(line); System.out.println("a+b=" + String.valueOf(a+b); catch(Exception e) System.out.println("輸入錯誤！&quo

35、t;); System.exit(0); 6.設計學生類Student，屬性：編號（整型）；姓名（字符串），成績（整型）。編寫一個程序：要求：（1）輸入3個學生的姓名和成績，將其姓名和成績保存到data.txt中；（2）然后從該文件中讀取數(shù)據(jù)，求得這五個學生的平均成績。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 nam

36、e) = 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;impo