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

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