20175209 实验二《Java面向对象程序设计》实验报告

20175209 实验二《Java面向对象程序设计》实验报告

一、实验前期准备

了解三种代码

• 伪代码
• 产品代码
• 测试代码

我们先写伪代码，伪代码
从意图层面来解决问题；
有了伪代码
我们用特定编程语言翻译一下，就是可用的产品代码；写完产品代码,接下来写测试代码
证明自己的代码没有问题。Java编程时，程序员对类实现的测试叫单元测试

二、Junit的安装和配置

• 在IDEA中点击Setting->Plugins->Marketplace 搜索Junit下载JUnitGenerator V2.0，下载后重启IDEA即可找到下载好的Junit

• Junit包的导入：File->Project Settings->Modules->Dependencies->‘+‘在你的安装IDEA的路径中找到lib文件夹导入图中的两个包后，点击OK即可正常使用

三、实验内容

任务1：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。

• 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){???????
    //如果成绩小于0，转成“错误”???????
    if ((grade < 0))???????????
        return "错误";???????????
    //如果成绩小于60，转成“不及格”???????
    else if (grade < 60)???????????
        return "不及格";???????????
    //如果成绩在60与70之间，转成“及格”???????
    else if (grade < 70)???????????
        return "及格";???????????
    //如果成绩在70与80之间，转成“中等”???????
    else if (grade < 80)???????????
        return "中等";???????????
    //如果成绩在80与90之间，转成“良好”???????
    else if (grade < 90)???????????
        return "良好";???????????
    //如果成绩在90与100之间，转成“优秀”???????
    else if (grade <= 100)???????????
        return "优秀";???????????
    //如果成绩大于100，转成“错误”???????
    else???????????
        return "错误";???
    }
}

• 测试代码

import org.junit.Test;
import junit.framework.TestCase;
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 testExceptions() {???????
        assertEquals("错误", MyUtil.percentage2fivegrade(105));???????
        assertEquals("错误", MyUtil.percentage2fivegrade(-55));???
    }???
    @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));???
    }
}

• 过程及结果截图

任务2：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。

• 产品代码

public class StringBufferDemo {??
    StringBuffer buffer = new StringBuffer();???
    public void StringBufferDemo (StringBuffer buffer) {???????
        this.buffer = buffer;???
    }???
    public Character charAt(int i) {???????
        return buffer.charAt(i);???
    }???
    public int capacity() {???????
        return buffer.capacity();???
    }???
    public int length() { ???????
        return buffer.length();???
    }???
    public int indexOf(String s) {???????
        return buffer.indexOf(s);???
    }
}

• 测试代码

import org.junit.Test;
public class StringBufferDemoTest extends TestCase {???
    StringBuffer a = new
    StringBuffer("StringBuffer");???
    StringBuffer b = new
    StringBuffer("StringBufferStringBuffer");???
    StringBuffer c = new StringBuffer("StringBuffer12345StringBuffer12345");???
    @Test???
    public void testcharAt() throws Exception {???????
        assertEquals('S',a.charAt(0));???????
        assertEquals('u',b.charAt(7));???????
        assertEquals('g',c.charAt(22));???
    }???
    @Test???
    public void testcapacity() throws? Exception {???????
        assertEquals(28,a.capacity());???????
        assertEquals(40,b.capacity());???????
        assertEquals(50,c.capacity());???
    }???
    @Test???
    public void testlength() throws? Exception {???????
        assertEquals(12,a.length());???????
        assertEquals(24,b.length());???????
        assertEquals(34,c.length());???
    }???
    @Test???
    public void testindexOf() throws Exception {???????
        assertEquals(6,a.indexOf("Buf"));???????
        assertEquals(11,b.indexOf("rSt"));???????
        assertEquals(15,c.indexOf("45St"));???
    }
}

• 对capacity()方法的理解：
  capacity()用于返回当前字符串的最大容量，初始值为16，即无论字符串中是否有内容，都会被分配容量，当有字符被写入是，容量自动增加，例如当输入StringBuffer 时会增加12个大小的空间，调用capacity()会返回当前字符串最大容量28
• 结果截图

任务3：

• 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。
  • S.O.L.I.D原则
    • SRP(Single Responsibility Principle,单一职责原则)
    • OCP(Open-Closed Principle,开放-封闭原则) 对扩充开放，对修改封闭：抽象和继承；面向接口编程
    • LSP(Liskov Substitusion Principle,Liskov替换原则)
    • ISP(Interface Segregation Principle,接口分离原则)
    • DIP(Dependency Inversion Principle,依赖倒置原则)

我的学号为9，按照要求题目应为3，即让系统支持Long类，代码如下：

public class MyDoc {???
static Document D;???
static Document E;???
public static void main(String[] args) {???????
    D = new Document(new IntFactory());???????
    D.DisplayData();???????
    E = new Document(new LongFactory());???????
    E.DisplayData();???
    }
}
abstract class Data {???
    abstract public void DisplayValue();
}
class Integer extends Data {???
    int value;???
    Integer() {???????
        value=100;???
    }???
    public void DisplayValue(){???????
        System.out.println (value);???
    }
}
class Long extends Data {???
    long value;???
    Long() {???????
        value = 1000000000;???
    }???
    public void DisplayValue() {???????
        System.out.println(value);???
    }
}
abstract class Factory {???
    abstract public Data CreateDataObject();
}
class IntFactory extends Factory {???
    public Data CreateDataObject(){???????
        return new Integer();???
    }
}
class LongFactory extends Factory {???
    public Data CreateDataObject(){???????
        return new Long();???
    }
}
class Document {???
    Data pd;???
    Document(Factory pf){???????
        pd = pf.CreateDataObject();???
    }???
    public void DisplayData(){???????
        pd.DisplayValue();???
    }
}

• 结果截图

任务四：以TDD的方式开发一个复数类Complex

• 伪代码

// 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)

• 产品代码

public class Complex {???
    double RealPart;???
    double ImagePart;???
    public Complex() {}???
    public Complex(double R,double I) {???????
        RealPart = R;???????
        ImagePart = I;???
    }???
    public double getRealPart() {???????
        return RealPart;???
    }???
    public double getImagePart() {???????
        return ImagePart;???
    }???
    public boolean equals(Object obj) {???????
        if(this == obj)???????????
            return true;???????
        if(obj == null)???????????
            return false;???????
        if(getClass() != obj.getClass())???????????
            return false;???????
        if(!(obj instanceof Complex))???????????
            return false;???????
        else {???????????
            Complex complex = (Complex) obj;???????????
            if (complex.ImagePart == ((Complex) obj).ImagePart)???????????????
                return true;???????????
            if (complex.RealPart == ((Complex) obj).RealPart)???????????????
                return true;???????
        }???????
        return false;???
    }???
    public? String toString() {???????
        String str = "";???????
        if (RealPart == 0&&ImagePart == 0)???????????
            str = "0.0";???????
        else if (RealPart == 0&&ImagePart != 0)???????????
            str = ImagePart + "" + "i";???????
        else if (RealPart != 0&&ImagePart == 0)???????????
            str = RealPart + "";???????
        else if (RealPart !=0&&ImagePart > 0)???????????
            str = RealPart + "" + "+" + ImagePart + "i";???????
        else if (RealPart !=0&&ImagePart < 0)???????????
            str = RealPart + "" + ImagePart + "i";???????
        return str;???
    }???
    public Complex ComplexAdd(Complex a) {???????
        return new Complex(RealPart + a.getRealPart(),ImagePart + a.getImagePart());???
    }???
    public? Complex ComplexSub(Complex a) {???????
        return new Complex(RealPart - a.getRealPart(),ImagePart - a.getImagePart());???
    }???
    public Complex ComplexMulti(Complex a) {???????
        return new Complex(RealPart*a.getRealPart() - ImagePart*a.getImagePart(),RealPart*a.getImagePart() +
ImagePart*a.getRealPart());???
    }???
    public Complex ComplexDiv(Complex a) {???????
        if(a.getRealPart() == 0&&a.getImagePart() == 0) {???????????
            System.out.println("除数不能为0");???????????
            return new Complex();???????
        }???????
        else ??????????
            return new Complex((RealPart*a.getRealPart() -
ImagePart*a.getImagePart())/(a.getRealPart()*a.getRealPart()-a.getImagePart()*a.getImagePart()),(RealPart*a.getImagePart() + ImagePart*a.getRealPart())/(a.getRealPart()*a.getRealPart()-a.getImagePart()*a.getImagePart()));???
    }
}

• 测试代码

import junit.framework.TestCase;
import org.junit.Test;
public class ComplexTest extends TestCase {???
    Complex a = new Complex(2.0,5.0);???
    Complex b = new Complex(1.0,-4.0);???
    Complex c = new Complex(-3.0,2.0);???
    Complex d = new Complex(-4.0,-3.0);???
    Complex e = new Complex(0.0,0.0);???
    @Test???
    public void testgetRealPart() throws Exception {???????
        assertEquals(2.0,a.getRealPart());???????
        assertEquals(1.0,b.getRealPart());???????
        assertEquals(-3.0,c.getRealPart());???????
        ssertEquals(-4.0,d.getRealPart());???????
        assertEquals(0.0,e.getRealPart());???
    }???
    @Test???
    public void testgetImagePart() throws Exception {???????
        assertEquals(5.0,a.getImagePart());???????
        assertEquals(-4.0,b.getImagePart());???????
        assertEquals(2.0,c.getImagePart());???????
        assertEquals(-3.0,d.getImagePart());???????
        assertEquals(0.0,e.getImagePart());???
    }???
    @Test???
    public void testequals() throws Exception {???????
        assertEquals(true,a.toString().equals(a.toString()));???????
        assertEquals(false,b.toString().equals(c.toString()));???????
        assertEquals(false,d.toString().equals(e.toString()));???
    }???
    @Test???
    public void testtoString() throws Exception {???????
        assertEquals("2.0+5.0i",a.toString());???????
        assertEquals("1.0-4.0i",b.toString());???????
        assertEquals("-3.0+2.0i",c.toString());???????
        assertEquals("-4.0-3.0i",d.toString());???????
        assertEquals("0.0",e.toString());???
    }???
    @Test???
    public void testComplexAdd() throws Exception {???????
        assertEquals("3.0+1.0i",a.ComplexAdd(b).toString());???????
        assertEquals("-7.0-1.0i",c.ComplexAdd(d).toString());???????
        assertEquals("-4.0-3.0i",d.ComplexAdd(e).toString());???
    }???
    @Test???
    public void testComplexSub() throws Exception {???????
        assertEquals("1.0+9.0i",a.ComplexSub(b).toString());???????
        assertEquals("1.0+5.0i",c.ComplexSub(d).toString());???????
        assertEquals("-3.0+2.0i",c.ComplexSub(e).toString());???
    }???
    public void testComplexMulti() throws Exception {???????
        assertEquals("22.0-3.0i",a.ComplexMulti(b).toString());???????
        assertEquals("18.0+1.0i",c.ComplexMulti(d).toString());???????
        assertEquals("0.0",b.ComplexMulti(e).toString());???
    }???
    public void testComplexDiv() throws Exception {???????
        assertEquals("-1.4666666666666666+0.2i",a.ComplexDiv(b).toString());???????
        assertEquals("2.5714285714285716+0.14285714285714285i",c.ComplexDiv(d).toString());???????
        assertEquals("0.0",a.ComplexDiv(e).toString());???
    }
}

• 结果截图

任务5：

• 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

选择画类图的题目为任务3

四、实验中遇到的问题

• 在按照博客中给的步骤进行任务2时按照给的代码输入后发现结果与所给的不同，反复测试后发现博客中代码存在问题，因为将代码12345添加至了第八行中，而这一行代码在执行时被注释掉不会被执行，但第五行的字符串和之前相比并没有发生改变，因此在运行时不会出现给出的结果，应该将代码12345添加至第五行的字符串末尾才能出现事例中的运行结果
  

五、脚本运行截图

六、代码托管

https://gitee.com/wangzihong/20175209/tree/master

原文地址：https://www.cnblogs.com/wangzihong0213/p/10733361.html