学号 20175313 《实验二面向对象程序设计》实验报告

实验二面向对象程序设计

实验二面向对象程序设计

一、前期准备

1. 熟悉三种代码的编写

伪代码
产品代码
测试代码

2. 学会 IDEA中配置单元测试工具JUnit
打开IDEA，选择File->Setting打开设置对话框
在设置对话框中选择Plugins, 单击Marketplace
选择JUnitGenerator V2.0,点击Install安装
安装好后可以在Installed里查看，如下图：
安装完成后，要开始配置。
- 我们在IDEA中新建一个项目，然后新建一个空类MyUtil:
- 鼠标右击类名，选择go to->test->Create New Test
- 弹出如下框框，选择JUnit3
这时你会发现你的测试代码放在了src文件夹中，为了区分源代码和测试代码，所以我新建了的一个test文件夹存放测试代码，并将其设置为Test Sources Root,这样你的测试代码就可以自动的放在该文件夹中。
显示TestCase是红色的，需要在IDEA中的项目中加入junit.jar包，junit.jar包:File->Project Structure->Dependancies->单击+->JARs or Directories

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二、实验内容

任务一：对MyUtil类进行测试，测试用例至少要包含正常情况，错误情况，边界情况的测试。
任务二：以TDD的方式研究学习StringBuffer，提交单元测试用例和测试通过的截图。
任务三：
- 对设计模式示例进行扩充，体会OCP原则和DIP原则的应用。
- 让系统支持Short类，并在MyDoc类中添加测试代码表明添加正确，提交测试代码和运行结的截图，加上学号水印。
任务四：以TDD的方式开发一个复数类Complex，要求如下:

// 定义属性并生成getter,setter
double RealPart;
double ImagePart;
// 定义构造函数
public Complex()
public Complex(double R,double I)

//Override Object
public boolean equals(Object obj)
public String toString()

// 定义公有方法:加减乘除
Complex ComplexAdd(Complex a)
Complex ComplexSub(Complex a)
Complex ComplexMulti(Complex a)
Complex ComplexDiv(Complex a)

任务五：
- 使用StarUML对实验二中的代码进行建模，发类图的截图，加上学号水印
- 类图中只少两个类
- 类，继承，接口实现，组合在UML中表达

三、实验步骤

任务一

伪代码：

百分制转五分制：
如果成绩小于60，转成“不及格”
如果成绩在60与70之间，转成“及格”
如果成绩在70与80之间，转成“中等”
如果成绩在80与90之间，转成“良好”
如果成绩在90与100之间，转成“优秀”
其他，转成“错误”

产品代码：

public class MyUtil {
    public static String percentage2fivegrade(int grade) {
        if (grade < 0)
            return "错误";
        else if(grade<60){
            return "不及格";
        }
        else if(grade<70){
            return "及格";
        }
        else if(grade<80){
            return "中等";
        }
        else if (grade<90){
            return "良好";
        }
        else if (grade<=100){
            return "优秀";
        }
        else
            return "错误";
    }
}

测试代码：

import junit.framework.TestCase;
import org.junit.Test;

public class MyUtilTest extends TestCase {
    @Test
    public void testNormal() {
        assertEquals("不及格", MyUtil.percentage2fivegrade(55));
        assertEquals("及格", MyUtil.percentage2fivegrade(65));
        assertEquals("中等", MyUtil.percentage2fivegrade(75));
        assertEquals("良好", MyUtil.percentage2fivegrade(85));
        assertEquals("优秀", MyUtil.percentage2fivegrade(95));
    }
    @Test
    public void testException(){
        assertEquals("错误",MyUtil.percentage2fivegrade(-55));
        assertEquals("错误",MyUtil.percentage2fivegrade(115));
    }
    @Test
    public void testBoundary(){
        assertEquals("不及格",MyUtil.percentage2fivegrade(0));
        assertEquals("及格",MyUtil.percentage2fivegrade(60));
        assertEquals("中等",MyUtil.percentage2fivegrade(70));
        assertEquals("良好",MyUtil.percentage2fivegrade(80));
        assertEquals("优秀",MyUtil.percentage2fivegrade(90));
        assertEquals("优秀",MyUtil.percentage2fivegrade(100));
    }

}

测试结果截图：

任务二
产品代码

public class StringBufferDemo {

    public StringBuffer setBuffer() {
        StringBuffer buffer = new StringBuffer();
        buffer.append('j');
        buffer.append("kjxlkjc");
        System.out.println(buffer.charAt(1));
        System.out.println(buffer.length());
        System.out.println(buffer.capacity());
        System.out.println(buffer.indexOf("jx"));
        System.out.println(buffer.toString());
        return buffer;
    }
}

测试代码

import junit.framework.TestCase;
import org.junit.Test;

public class StringBufferDemoTest extends TestCase {
    StringBuffer buffer1 = new StringBuffer();
    StringBuffer buffer2 = new StringBuffer("i am a student");
    StringBuffer buffer3 = new StringBuffer("i like java");
    StringBufferDemo stringBufferDemo = new StringBufferDemo();
    @Test
    public void testcharAt() {
        buffer1.append('h');
        buffer1.append("ello java");
        assertEquals('l',buffer1.charAt(2));
        assertEquals('h',buffer1.charAt(0));
        assertEquals('k',stringBufferDemo.setBuffer().charAt(1));
    }
    @Test
    public void testlength(){
        assertEquals(0,buffer1.length());
        assertEquals(14,buffer2.length());
        assertEquals(11,buffer3.length());
        assertEquals(8,stringBufferDemo.setBuffer().length());
    }
    @Test
    public void testcapacity(){
        assertEquals(16,buffer1.capacity());
        assertEquals(30,buffer2.capacity());
        assertEquals(27,buffer3.capacity());
        assertEquals(16,stringBufferDemo.setBuffer().capacity());
    }
    public void testToString(){
        assertEquals("",buffer1.toString());
        assertEquals("i am a student",buffer2.toString());
        assertEquals("i like java",buffer3.toString());
        assertEquals("jkjxlkjc",stringBufferDemo.setBuffer().toString());
    }
    public void testIndexOf(){
        assertEquals(0,buffer1.indexOf(""));
        assertEquals(2,buffer2.indexOf("am a st"));
        assertEquals(7,buffer3.indexOf("java"));
        assertEquals(2,stringBufferDemo.setBuffer().indexOf("jxlk"));
    }

}

测试结果截图：

任务三
产品代码

// Server Classes
abstract class Data {
    abstract public void DisplayValue();
}
class Integer extends  Data {
    int value;
    Integer() {
        value=100;
    }
    @Override
    public void DisplayValue(){
        System.out.println (value);
    }
}
class Short extends  Data {
    int value;
    Short() {
        value=5;
    }
    @Override
    public void DisplayValue(){
        System.out.println (value);
    }
}
abstract class Factory {
    abstract public Data CreateDataObject();
}
class IntFactory extends Factory {
    @Override
    public Data CreateDataObject(){
        return new Integer();
    }
}
class ShortFactory extends Factory {
    @Override
    public Data CreateDataObject(){
        return new Short();
    }
}
class Document {
    Data pd;
    Document(Factory pf){
        pd = pf.CreateDataObject();
    }
    public void DisplayData(){
        pd.DisplayValue();
    }
}
public class MyDoc {
    static Document d;
    public static void main(String[] args) {
        d = new Document(new IntFactory());
        d.DisplayData();
        d = new Document(new ShortFactory());
        d.DisplayData();
    }
}

运行结果截图：

任务四
产品代码

import java.text.DecimalFormat;
public class Complex {
    double RealPart;
    double ImagePart;
    public Complex(){

    }
    public Complex(double R,double I){
        RealPart = R;
        ImagePart = I;
    }
    public void setter(double R,double I){
        RealPart = R;
        ImagePart = I;
    }
    public double getterRealPart(){
        return RealPart;
    }
    public double getterImagePart(){
        return ImagePart;
    }
    @Override
    public boolean equals(Object obj){
        if(this==obj){
            return true;
        }
        else
        {
            return false;
        }
    }
    @Override
    public String toString(){
        String s = "";
        if(getterRealPart()==0&&getterImagePart()==0){
            s="0";
        }
        else if(getterRealPart()!=0&&getterImagePart()==0){
            s=s+getterRealPart();
        }
        else if (getterRealPart()==0&&getterImagePart()!=0){
            s=s+getterImagePart()+"i";
        }
        else
        {
            if(getterImagePart()<0){
                s = s+getterRealPart()+getterImagePart()+"i";
            }
            else {
                s = s+getterRealPart()+"+"+getterImagePart()+"i";
            }

        }
        return s;
    }
    public Complex ComplexAdd(Complex a){
        return new Complex((getterRealPart()+a.getterRealPart()),(getterImagePart()+a.getterImagePart()));
    }
    public Complex ComplexSub(Complex a){
        return new Complex((getterRealPart()-a.getterRealPart()),(getterImagePart()-a.getterImagePart()));
    }
    public Complex ComplexMulti(Complex a){
        double imaginePart = getterRealPart()*a.getterImagePart()+getterImagePart()*a.getterRealPart();
        double realPart = getterRealPart()*a.getterRealPart()-getterImagePart()*a.getterImagePart();
        return new Complex(realPart,imaginePart);
    }
    public Complex ComplexDiv(Complex a) throws Exception {
        double imaginePart = -getterRealPart()*a.getterImagePart()+getterImagePart()*a.getterRealPart();
        double realPart = getterRealPart()*a.getterRealPart()+getterImagePart()*a.getterImagePart();
        double div = a.getterRealPart()*a.getterRealPart()+a.getterImagePart()*a.getterImagePart();
        if(div==0){
            throw new Exception();
        }
        realPart = realPart/div;
        imaginePart = imaginePart/div;
        DecimalFormat decimalFormat = new DecimalFormat("0.0");
        return new Complex(Double.valueOf(decimalFormat.format(realPart)),Double.valueOf(decimalFormat.format(imaginePart)));
    }
}

测试代码

import junit.framework.TestCase;
import org.junit.Test;

public class ComplexTest extends TestCase {
    Complex complex = new Complex(34,56);
    Complex complex2 = new Complex();
    public void testGetterRealPart() {
        assertEquals(34.0,complex.getterRealPart());
        complex.setter(0,-1);
        assertEquals(0.0,complex.getterRealPart());
        complex.setter(-3.6,5);
        assertEquals(-3.6,complex.getterRealPart());
    }

    public void testGetterImagePart() {
        assertEquals(56.0,complex.getterImagePart());
        complex.setter(34,-56.989);
        assertEquals(-56.989,complex.getterImagePart());
        complex.setter(4,0);
        assertEquals(0.0,complex.getterImagePart());
    }

    public void testEquals() {
        assertTrue(complex.equals(complex));
        Complex complex2 = new Complex();
        assertFalse(complex.equals(complex2));
    }

    public void testToString() {
        complex.setter(0,0);
        assertEquals("0",complex.toString());
        complex.setter(0.2,3);
        assertEquals("0.2+3.0i",complex.toString());
        complex.setter(4.5,0);
        assertEquals("4.5",complex.toString());
        complex.setter(0,6);
        assertEquals("6.0i",complex.toString());
        complex.setter(-5.6,-6.7);
        assertEquals("-5.6-6.7i",complex.toString());
    }

    public void testComplexAdd() {
        complex2 = complex.ComplexAdd(new Complex(-33,-57));
        assertEquals("1.0-1.0i",complex2.toString());
        assertEquals("35.0+55.0i",complex2.ComplexAdd(complex).toString());
    }

    public void testComplexSub() {
        complex2 = complex.ComplexSub(new Complex(33,57));
        assertEquals("1.0-1.0i",complex2.toString());
        assertEquals("-33.0-57.0i",complex2.ComplexSub(complex).toString());
    }

    public void testComplexMulti() {
        complex.setter(-3.5,5);
        complex2.setter(0,0);
        assertEquals("0",complex.ComplexMulti(complex2).toString());
        complex2.setter(10,-3);
        assertEquals("-20.0+60.5i",complex.ComplexMulti(complex2).toString());
    }
    @Test(expected = Exception.class)
    public void testComplexDiv() throws Exception{
        complex.setter(3,3);
        complex2.setter(0,9);
        assertEquals("0.3-0.3i",complex.ComplexDiv(complex2).toString());
        complex.setter(0,0);
        assertEquals("0",complex.ComplexDiv(complex2).toString());
    }
}

测试结果截图：

任务五

四、实验过程中遇到的问题及其解决

问题一：在进行Junit配置时找不到juint.jar和juint-4.12.jar这两个包
解决方法：向别人拷贝lib文件夹
问题二：在选择Testing library时,选择Junit4,对test文件运行时，程序报错。
解决方法：在选择Testing library时,选择Junit3。
问题3：对于append方法的使用了解的不够透彻，认为使用append会扩大capacity的值
通过测试查看期待结果与实际结果的差别以及查看帮助文档，了解append方法的使用。
测试结果截图:
问题4：按照老师给的博客里的参考代码进行测试MyDoc，出现如下问题：
解决方法：在出现错误的方法前加上@override
问题5：解决完问题4后我发现我之前运行成功的源代码出现的如下问题：
解决方法：点击小灯泡，按照提示做。
问题6：对比了好久两个明明都是0，为什么会报错呢？
解决方法：认真查看自己的测试代码，发现一个是字符串的0，一个是数字0，于是将测试代码complex.ComplexMulti(complex2)调用toString方法将其转化为字符串。
问题7：对Complex类中的除法，得出的结果无法确定小数点的位数，所以对其做测试时无法pass。
解决方法：import java.text.DecimalFormat;，DecimalFormat df = new DecimalFormat( "0.0");将计算后得到的结果小数位数控制在一位。