如何可以评估JAVA的水平

实验报告封面

实验内容及步骤

实验一、实现百分制成绩转成“优、良、中、及格、不及格”五级制成绩的功能

代码

public class MyUtil{
    public static String percentage2fivegrade(int grade) {
        if (grade < 0  || grade >100)
            return "错误";
        //如果成绩小于60，转成“不及格”
        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";
            //其他，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));
    }

}

实验截图

实验二、以TDD的方式研究学习StringBuffer

代码

public class StringBufferDemo {
    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("tring12345"));
        //System.out.println("buffer = " + buffer.toString());
        //System.out.println(buffer.length());
    }
}

测试代码

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

public class StringBufferDemoTest extends TestCase {
        StringBuffer a = new StringBuffer("StringBuffer");
        //测试12个字符
        StringBuffer b = new StringBuffer("StringBufferStringBuffer");
        //测试24个字符
        StringBuffer c = new StringBuffer("StringBufferStringBufferStringBuffer");
        //测试36个字符
        StringBuffer d = new StringBuffer("StringBufferStringBufferStringBufferStr");
        //测试39个字符
        @Test
        public void testcharAt() {
            assertEquals('S',a.charAt(0));
            assertEquals('e',b.charAt(10));
            assertEquals('f',c.charAt(20));
            assertEquals('B',d.charAt(30));
        }
        @Test
        public void testcapacity() {
            assertEquals(28,a.capacity());
            assertEquals(40,b.capacity());
            assertEquals(52,c.capacity());
            assertEquals(55,d.capacity());
        }
        @Test
        public void testindexOf() {
            assertEquals(0,a.indexOf("Str"));
            assertEquals(3,b.indexOf("ing"));
            assertEquals(6,c.indexOf("Buffer"));
            assertEquals(8,d.indexOf("ff"));
        }
        @Test
        public void testlength() {
            assertEquals(12,a.length());
            assertEquals(24,b.length());
            assertEquals(36,c.length());
            assertEquals(39,d.length());
        }

}

实验截图

实验三、对设计模式示例进行扩充，体会OCP原则和DIP原则的应用，初步理解设计模式

代码

// Server Classes 
abstract class Data {
    abstract public void DisplayValue();
}
class Integer extends  Data {
    int value;
    Integer() {
        value=100;
    }
    public void DisplayValue(){
        System.out.println (value);
    }
}
class Short extends Data {
    short value;
    Short() {
        value = 5337;
    }
    public void DisplayValue(){
        System.out.println (value);
    }
}
// Pattern Classes 
abstract class Factory {
    abstract public Data CreateDataObject();
}
class IntFactory extends Factory {
    public Data CreateDataObject(){
        return new Integer();
    }
}
class ShortFactory extends Factory {
    public Data CreateDataObject(){
        return new Short();
    }
}
//Client classes 
class Document {
    Data pd;
    Document(Factory pf){
        pd = pf.CreateDataObject();
    }
    public void DisplayData(){
        pd.DisplayValue();
    }
}
//Test class
public class MyDoc {
    static Document d;
    public static void main(String[] args) {
        d = new Document(new ShortFactory());
        d.DisplayData();
    }
}

实验四、以TDD的方法开发一个复数类Complex

代码

public class Complex {
    public double getRealPart() {
        return RealPart;
    }

    public double getImagePart() {
        return ImagePart;
    }

    double RealPart;
    double ImagePart;

    public void setRealPart(double realPart) {
        RealPart = realPart;
    }

    public void setImagePart(double imagePart) {
        ImagePart = imagePart;
    }

    public Complex(){}
    public Complex(double R,double I){
        this.ImagePart = I;
        this.RealPart = R;
    }


    @Override
    public String toString() {
        return "Complex{" +
                "RealPart=" + RealPart +
                ", ImagePart=" + ImagePart +
                '}';
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Complex complex = (Complex) o;
        return Double.compare(complex.getRealPart(), getRealPart()) == 0 &&
                Double.compare(complex.getImagePart(), getImagePart()) == 0;
    }

    Complex ComplexAdd(Complex a) {
        return new Complex(this.RealPart + a.RealPart,this.ImagePart + a.ImagePart);
    }
    Complex ComplexSub(Complex a){
        return new Complex(this.RealPart - a.RealPart,this.ImagePart - a.ImagePart);
    }
    Complex ComplexMulti(Complex a){
        return new Complex(this.RealPart*a.RealPart-this.ImagePart*a.ImagePart,
                this.ImagePart*a.RealPart+this.RealPart*a.ImagePart);
    }
    Complex ComplexDiv(Complex a){
        double scale = a.getRealPart()*a.getRealPart() + a.getImagePart()*a.getImagePart();
        Complex b = new Complex(a.getRealPart() / scale, - a.getImagePart() / scale);
        return this.ComplexMulti(b);
    }
}

测试代码

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

public class ComplexTest extends TestCase {
    Complex a = new Complex(5.0, 6.0);
    Complex b = new Complex(-3.0, 4.0);

    @Test
    public void testgetRealPart() {
        assertEquals(5.0,a.getRealPart());
        assertEquals(-3.0,b.getRealPart());
    }

    @Test
    public void testgetImagePart() {
        assertEquals(6.0,a.getImagePart());
        assertEquals(4.0,b.getImagePart());
    }

    @Test
    public void testtoString() {
        assertEquals("Complex{RealPart=5.0, ImagePart=6.0}",a.toString());
        assertEquals("Complex{RealPart=-3.0, ImagePart=4.0}",b.toString());
    }

    @Test
    public void testequals() {
        assertEquals(false,a.equals(b));
        Complex c = new Complex(a.getRealPart(),a.getImagePart());
        assertEquals(true,a.equals(c));
    }

    @Test
    public void testComplexAdd() {
        assertEquals(2.0,a.ComplexAdd(b).getRealPart());
        assertEquals(10.0,a.ComplexAdd(b).getImagePart());
    }

    @Test
    public void testComplexSub() {
        assertEquals(8.0,a.ComplexSub(b).getRealPart());
        assertEquals(2.0,a.ComplexSub(b).getImagePart());
    }

    @Test
    public void testComplexMulti() {
        assertEquals(-39.0,a.ComplexMulti(b).getRealPart());
        assertEquals(2.0,a.ComplexMulti(b).getImagePart());
    }

    @Test
    public void testComplexDiv() {
        assertEquals(0.36,a.ComplexDiv(b).getRealPart());
        assertEquals(-1.52,a.ComplexDiv(b).getImagePart());
    }
}

实验截图

实验五、代码建模

实验PSP

步骤	耗时	百分比
需求分析	20分钟	4.7%
设计	20分钟	4.7%
代码实现	200分钟	47%
测试	80分钟	19%
分析总结	100分钟	23.8%

遇到的问题

在使用IDEA的过程中，我的Junit安装不了，后来问同学得知可以从电脑找到后再导入。但是我的APPdata文件夹找不到，后来发现是被系统隐藏了，在使用管理员权限显示后就好了。