2017-2018-2 20165312实验二《Java面向对象程序设计》实验报告

2017-2018-2 20165312实验二《Java面向对象程序设计》实验报告

实验中遇到的问题

1.增加MyUtil的测试类之后，TestCase是红色的，但是没有找到junit.jar包的地方

解决方法：

• 找到电脑中IDEA安装路径

• 打开File->Project Structure
• 点击Dependencies,单击右上角的+,然后选择第一个JARs or directories
• 复制刚才的路径名，找到junit-4.12 jar 、 junit.jar

• 选择junit-4.12 jar 、 junit.jar两项，并点击下方Ok

2.在做第二个实验的时候，运行测试代码时出现了问题

并不是产品代码的问题，而是测试代码的问题。

@Test
public void testcharAt(){
    assertEquals("S",buffer.charAt(0));
    }
@Test
public void testcapacity(){
    assertEquals("28",buffer.capacity());
    
}
@Test
public void testindexof(){
    assertEquals("1",buffer.indexOf("tring"));
}

"S" "28" “1”是错误的

正确代码：

@Test
public void testcharAt(){
    assertEquals('S',buffer.charAt(0));
}
@Test
public void testcapacity(){
    assertEquals(28,buffer.capacity());
}
@Test
public void testindexof(){
    assertEquals(1,buffer.indexOf("tring"));
}

知识点总结

• 伪代码
• 产品代码
  • Java编程时，程序员对类实现的测试叫单元测试。
  • 测试用例是为某个特殊目标而编制的一组测试输入、执行条件以及预期结果，以便测试某个程序路径或核实是否满足某个特定需求。
• 先写测试代码，然后再写产品代码的开发方法叫“测试驱动开发”（TDD）
• 面向对象三要素是“封装、继承、多态”，任何面向对象编程语言都会在语法上支持这三要素。S.O.L.I.D类设计原则：
  • SRP(Single Responsibility Principle,单一职责原则)
  • OCP(Open-Closed Principle,开放-封闭原则)
  • 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)

五项实验任务

一、学生成绩等级制

题目要求：测试用例（正常情况，错误情况，边界情况）都通过

产品代码：

/**
 * Created by CaoGe on 2018/4/14.
 */
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 junit.framework.TestCase;
import org.junit.Test;
/**
 * Created by CaoGe on 2018/4/14.
 */
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("不及格",MyUtil.percentage2fivegrade(55));
        assertEquals("不及格",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));
    }
}

运行截图：

二、TDD的方式研究学习StringBuffer

---

产品代码：

public class StringBufferExercise {
    public static void main(String [] args){
        StringBuffer buffer = new StringBuffer();
        buffer.append('S');
        buffer.append("tringBuffer");
        System.out.println(buffer.charAt(1));
        System.out.println(buffer.capacity());
        System.out.println(buffer.indexOf("tring"));
        System.out.println("buffer = " + buffer.toString());
    }
}

测试代码：

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

public class StringBufferExerciseTest extends TestCase {
    StringBuffer buffer = new StringBuffer("StringBuffer");
    @Test
    public void testcharAt(){
        assertEquals('S',buffer.charAt(0));
    }
    @Test
    public void testcapacity(){
        assertEquals(28,buffer.capacity());
    }
    @Test
    public void testindexof(){
        assertEquals(1,buffer.indexOf("tring"));
    }
    @Test
    public void testtoString(){
        assertEquals("StringBuffer",buffer.toString());
    }
}

运行截图：

三、体会OCP原则和DIP原则的应用

题目要求：让系统支持Byte类，并在MyDoc类中添加测试代码表明添加正确。

产品代码如下：

import java.util.Objects;
abstract class Data {
    abstract public void DisplayValue();
}
class Byte extends Data {
    byte value1;
    byte value2;
    Byte() {
        value1=53;
        value2=12;
    }
    public void DisplayValue(){
        System.out.println (value1);
        System.out.println (value2);
    }
}
// Pattern Classes
abstract class Factory {
    abstract public Data CreateDataObject();
}
class ByteFactory extends Factory {
    public Data CreateDataObject(){
        return new Byte();
    }
}
//Client classes
class Document {
    Data data;
    Document(Factory factory){
        data = factory.CreateDataObject();
    }
    public void DisplayData(){
        data.DisplayValue();

    }
}
public class MyDoc {
    static Document d;
    MyDoc(Document d) {
        this.d = d;
    }
    public static void main(String[] args) {
        d = new Document(new ByteFactory());
        d.DisplayData();
    }
}

运行截图如下：

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)

产品代码：

public class Complex{
    private double r;
    private double i;

    public Complex(double r, double i) {
        this.r = r;
        this.i = i;
    }

    public static double getRealPart(double r) {
        return r;
    }

    public static double getImagePart(double i) {
        return i;
    }

    public Complex ComplexAdd(Complex c) {
        return new Complex(r + c.r, i + c.i);
    }
    public Complex ComplexSub(Complex c) {
        return new Complex(r - c.r, i - c.i);
    }
    public Complex ComplexMulti(Complex c) {
        return new Complex(r * c.r - i * c.i, r * c.i + i * c.r);
    }
    public Complex ComplexDiv(Complex c) {
        return new Complex((r * c.i + i * c.r)/(c.i * c.i + c.r * c.r), (i * c.i + r * c.r)/(c.i * c.i + c.r * c.r));
    }

    public String toString() {
        String s = " ";
        if (i > 0)
            s =  r + "+" + i + "i";
        if (i == 0)
            s =  r + "";
        if (i < 0)
            s = r + " " + i + "i";
        return s;
    }
}

测试代码：

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

public class ComplexTest extends TestCase {
    Complex c1 = new Complex(0, 3);
    Complex c2 = new Complex(-1, -1);
    Complex c3 = new Complex(2,1);
    @Test
    public void testgetRealPart() throws Exception {
        assertEquals(-1.0, Complex.getRealPart(-1.0));
        assertEquals(5.0, Complex.getRealPart(5.0));
        assertEquals(0.0, Complex.getRealPart(0.0));
    }
    @Test
    public void testgetImagePart() throws Exception {
        assertEquals(-1.0, Complex.getImagePart(-1.0));
        assertEquals(5.0, Complex.getImagePart(5.0));
        assertEquals(0.0, Complex.getImagePart(0.0));
    }
    @Test
    public void testComplexAdd() throws Exception {
        assertEquals("-1.0+2.0i", c1.ComplexAdd(c2).toString());
        assertEquals("2.0+4.0i", c1.ComplexAdd(c3).toString());
        assertEquals("1.0", c2.ComplexAdd(c3).toString());
    }
    @Test
    public void testComplexSub() throws Exception {
        assertEquals("1.0+4.0i", c1.ComplexSub(c2).toString());
        assertEquals("-2.0+2.0i", c1.ComplexSub(c3).toString());
        assertEquals("-3.0 -2.0i", c2.ComplexSub(c3).toString());
    }
    @Test
    public void testComplexMulti() throws Exception {
        assertEquals("3.0 -3.0i", c1.ComplexMulti(c2).toString());
        assertEquals("-3.0+6.0i", c1.ComplexMulti(c3).toString());
        assertEquals("-1.0 -3.0i", c2.ComplexMulti(c3).toString());
    }
    @Test
    public void testComplexComplexDiv() throws Exception {
        assertEquals("-1.5 -1.5i", c1.ComplexDiv(c2).toString());
        assertEquals("1.2+0.6i", c1.ComplexDiv(c3).toString());
        assertEquals("-0.6 -0.6i", c2.ComplexDiv(c3).toString());
    }
}

运行截图：

五、使用StarUML对实验二中的代码进行建模

我对第三个实验画了UML图

步骤	耗时	百分比
需求分析	2h	16%
设计	1h	8%
代码实现	2h	16%
测试	2h	16%
分析总结	3h	25%