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
