实验报告 5 java常用类(一)

1、西 安 邮 电 大 学（计算机学院）面向对象程序设计JAVA 课内实验报告 实验名称: Java类库和常用类（二） 专业名称: 班 级: 学生姓名: 学号(8位): 指导教师: 实验时间: 1. 实验目的及实验环境实验目的： 1理解类库的概念，掌握分析、应用类库中的类的方法。 2熟练掌握Math类的常用方法。熟悉Random类的常用方法。 3理解String类的特性，熟练掌握String类的常用方法。 4能用Date类创建对象，熟练掌握Date类的常用方法。 5熟练掌握SimpleDateFormat解析日期和设置日期输出格式。 6学会查阅Java API在线参考文档和离线文档的方法。实验环境

2、：Eclipse for java2. 实验内容 1 基本内容（实验前请及时熟悉如下相关内容） 1）练习使用Math类的常用方法。 2）应用String类编程练习。 3）编写程序应用Random类生成随机数。 4）练习使用Date类的常用方法。 5）查阅Java API在线参考文档和下载Java API离线文档。 2 综合实验：2.1 (Y. Daniel Liang英文版八版P296：8.3*) (Using the Date class) Write a program that creates a Date object, sets its elapsed time to 10000,

3、100000, 10000000, 10000000, 100000000, 1000000000, 10000000000, 100000000000, and displays the date and time using the toString() method, respectively.2.2(Y. Daniel Liang英文版八版P296：8.4*) (Using the Random class) Write a program that creates a Random object with seed 1000 and displays the first 50 ran

4、dom integers between 0 and 100 using the nextInt(100) method.2.3 (Y. Daniel Liang英文版八版P296：8.5*) (Using the GregorianCalendar class) Java API has the GregorianCalendar class in the java.util package that can be used to obtain the year, month, and day of a date. The no-arg constructor constructs an i

5、nstance for the current date, and the methods get(GregorianCalendar.YEAR), get(GregorianCalendar.MONTH), and get(GregorianCalendar.DAY_OF_MONTH) return the year, month, and day.Write a program to perform two tasks: Display the current year, month, and day. The GregorianCalendar class has the setTime

6、InMillis(long), which can be used to set a specified elapsed time since January 1, 1970. Set the value to 1234567898765L and display the year, month, and day.2.4(Y. Daniel Liang英文版八版P337：9.11*) (Sorting characters in a string) Write a method that returns a sorted string using the following header:pu

7、blic static String sort(String s)For example, sort("acb") returns abc.Write a test program that prompts the user to enter a string and displays the sorted string.2.5(Y. Daniel Liang英文版八版P338：9.15*) (Finding the number of uppercase letters in a string) Write a program that passes a string t

8、o the main method and displays the number of uppercase letters in a string.3 方案设计（核心代码和流程设计）四测试数据及运行结果1正常测试数据及运行结果；2正常测试数据及运行结果；3 正常测试数据及运行结果；4. 正常测试数据及运行结果5. 正常测试数据及运行结果五总结1 实验过程中遇到的问题及解决办法。2 对设计及调试过程的心得体会。6 附录：源代码（请把源代码按照实验内容附到其后）2_1 Using the Date classimport java.util.Date;import java.text.Simpl

9、eDateFormat;class toString public toString(long s) Date date = new Date(s); SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); String str = format.format(date); System.out.println(str); public class DisplayDate public static void main(String args) toString str1 = new to

10、String(10000); toString str2 = new toString(100000); toString str3 = new toString(1000000); toString str4 = new toString(10000000); toString str5 = new toString(100000000); toString str6 = new toString(1000000000); toString str7 = new toString(10000000000L); toString str8 = new toString(100000000000

11、L); 2_2 Using the Random classimport java.util.*;public class RandomFigure public static void main(String args) Random rd = new Random(1000); for (int i=0; i<50; i+) int in = rd.nextInt(101); System.out.print(in + " "); 2_3 Using the GregorianCalendar classimport java.util.*;public clas

12、s PrintDate public static void main(String args) GregorianCalendar date = new GregorianCalendar(); int year1 = date.get(GregorianCalendar.YEAR); int month1 = date.get(GregorianCalendar.MONTH); int day1 = date.get(GregorianCalendar.DAY_OF_MONTH); System.out.println("当前日期: " + year1 + "

13、年" + month1 + "月" + day1 + "日"); date.setTimeInMillis(1234567898765L); int year2 = date.get(GregorianCalendar.YEAR); int month2 = date.get(GregorianCalendar.MONTH); int day2 = date.get(GregorianCalendar.DAY_OF_MONTH); System.out.println("特定日期: " + year2 + "年&q

14、uot; + month2 + "月" + day2 + "日"); 2_4 Sorting characters in a stringimport java.util.*;class StrSort public static String sort(String s) char str = s.toCharArray(); for (int i = 0; i < s.length(); i+) for (int j = 0; j < i; j+) if (stri < strj) char t = stri; stri = str

15、j; strj = t; return String.valueOf(str); public class StringSort public static void main(String args) System.out.print("Please input a string: ");Scanner s = new Scanner(System.in);String a = s.nextLine(); System.out.println("排序后的字符串: " + StrSort.sort(a); 2_5 Finding the number of uppercase letters in a stringimport java.util.*;public class PrintUpperNumber public static void main(String args) System.out.print("Please input a string: ");Scan