Java – JUnit test case for database insertion method using DAO and Web Services

I am implementing a university management system based on Web services The system adds some courses to the database Here's the code I'm using

Course. java

public class Course {

    private String courseName;
    private String location;
    private String courseId;


       public String getCourseId()
               {
        return courseId;
            }

    public void setCourseId(String courseId) {
        this.courseId = courseId;
    }

    public String getCourseName() {
        return courseName;
    }

    public void setCourseName(String courseName) {
        this.courseName = courseName;
    }

        public String getLocation() {
        return location;
    }
    public void setLocation(String location) {
        this.location = location;
    }
}

Then another file is as follows

CourseDaoImpl. java

public class CourseDaoImpl implements IDao {
   Connection conn = null;
   Statement stmt = null;

public CourseDaoImpl(){

try {
    Class.forName("com.MysqL.jdbc.Driver").newInstance();
    conn = DriverManager.getConnection(
            "jdbc:MysqL://localhost:3306/univesitydb","root","root");
    stmt = conn.createStatement();

    if (!conn.isClosed())
        System.out.println("Successfully connectiod");
} catch (sqlException e) {
    e.printStackTrace();
} catch (InstantiationException e) {
    e.printStackTrace();
} catch (illegalaccessexception e) {
    e.printStackTrace();
} catch (ClassNotFoundException e) {
    e.printStackTrace();
}
}

      @Override
  public String add(Object object) {

Course c = (Course) object ;

String courseId = c.getCourseId();
String courseName = c.getCourseName();
String location = c.getLocation();

String result = "";
int rowcount;

try {
    String query = "Insert into course (courseId,courseName,location) values"
            + " ('"
            + courseId
            + "','"
            + courseName
            + "','"
            + location
            + "')";
    rowcount = stmt.executeUpdate(query);
    if (rowcount > 0) {
        result = "true";
        System.out.println("Course inserted successful");
    } else {
        result = "false:The data Could not be inserted in the databse";
    }
} catch (sqlException e) {
    e.printStackTrace();
}

return result;
}

The third is the following web service file, which interacts with the first two and adds data to the database

CourseService. java

package edu.service;

          import edu.dao.IDao;
          import edu.dao.impl.CourseDaoImpl;
          import edu.db.entity.Course;

       public class CourseService {

     public String addCourse(String courseId,String courseName,String location)
    {   
       Course c = new Course();
       c.setCourseId(courseId);
       c.setCourseName(courseName);
       c.setLocation(location);     
       IDao dao = new CourseDaoImpl();
       return dao.add(c);   
     }

Looking at my code listing, any organization can advise me how to write test cases for my add method I am a beginner of Java. I learned this Java part from my friends. Now I need to implement JUnit test for my database method, such as the addition course above

Please suggest something I can learn, read and use to implement JUnit testing of my database methods

Solution

This is an example Dao test using JUnit in a spring project

import java.util.List;

import junit.framework.Assert;

import org.jboss.tools.example.springmvc.domain.Member;
import org.jboss.tools.example.springmvc.repo.MemberDao;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.test.context.transaction.TransactionConfiguration;
import org.springframework.transaction.annotation.Transactional;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations={"classpath:test-context.xml","classpath:/Meta-INF/spring/applicationContext.xml"})
@Transactional
@TransactionConfiguration(defaultRollback=true)
public class MemberDaoTest
{
    @Autowired
    private MemberDao memberDao;

    @Test
    public void testFindById()
    {
        Member member = memberDao.findById(0l);

        Assert.assertEquals("John Smith",member.getName());
        Assert.assertEquals("john.smith@mailinator.com",member.getEmail());
        Assert.assertEquals("2125551212",member.getPhoneNumber());
        return;
    }

    @Test
    public void testFindByEmail()
    {
        Member member = memberDao.findByEmail("john.smith@mailinator.com");

        Assert.assertEquals("John Smith",member.getPhoneNumber());
        return;
    }

    @Test
    public void testRegister()
    {
        Member member = new Member();
        member.setEmail("jane.doe@mailinator.com");
        member.setName("Jane Doe");
        member.setPhoneNumber("2125552121");

        memberDao.register(member);
        Long id = member.getId();
        Assert.assertNotNull(id);

        Assert.assertEquals(2,memberDao.findAllOrderedByName().size());
        Member newMember = memberDao.findById(id);

        Assert.assertEquals("Jane Doe",newMember.getName());
        Assert.assertEquals("jane.doe@mailinator.com",newMember.getEmail());
        Assert.assertEquals("2125552121",newMember.getPhoneNumber());
        return;
    }

    @Test
    public void testFindAllOrderedByName()
    {
        Member member = new Member();
        member.setEmail("jane.doe@mailinator.com");
        member.setName("Jane Doe");
        member.setPhoneNumber("2125552121");
        memberDao.register(member);

        List<Member> members = memberDao.findAllOrderedByName();
        Assert.assertEquals(2,members.size());
        Member newMember = members.get(0);

        Assert.assertEquals("Jane Doe",newMember.getPhoneNumber());
        return;
    }
}