mybatis-spring-zk

Sample application demonstrating integration of MyBatis 3.1, Spring 3.1, and ZK 6.5.0 (MVVM)

To build:
Requires maven
From project directory: mvn clean install

To deploy:
Move the generated employee-maintenance.war file in target/ to your app server's deploy dir (eg tomcat/webapps) and start your server.

URL: http://localhost:8080/employee-maintenance/

NOTES:

Application uses an internal in-memory HSQLDB defined in spring/services-config.xml. You'll see a commented out section in the config demonstrating using your typical datasouce declaration using an external server DB instance.

You'll notice that I'm using both services classes and MyBatis mappers. Because this application is so simple, you really could just use the Mappers directly in your ViewModels. All the service class methods do in this application is end up calling the appropriate mapper methods. However in "real life" I've found that you often perform some other business logic in your service class methods before calling your mappers. For example your service class for doing an insert might also involve updating some other tables after the insert, or possible sending out a notification message. Having a service class, can keep unwanted business logic from creeping into your ViewModel. Of course, feel free to skip using the service class approach if you so desire. There is nothing inherently wrong with using your mappers directly in your ViewModel.

There are sample filters included. By default the local is used when you do a build. For this sample application the filters don't do much since we're using a standalone internal db, but in real life you'd have different datasource properties for different environments. The filter will replace the appropriate wildcards in anything under web-inf (you could change this in your pom.) The filter currently replaces the wildcards in web-application.properties and the spring config files (in real life the datasource you see commented out in services-config.xml would be replaced based on your filter.) To build using a different profile, for example the qa version, you'd just switch to building with a different profile from maven: mvn clean install -P qa

MyBatis

Many people might be coming at this from experience with ORMs such as Hibernate. MyBatis isn't an ORM tool but a sql mapping tool. I prefer using MyBatis, but not going to get into all the reasons why in this readme. The basics with Spring here are really simple.

In the services-config.xml you'll see the setup. This tells MyBatis what datasource to use, where the domain objects are located, and where the mapper files are locaated:

<jdbc:embedded-database id="empDS" type="HSQL">
	<jdbc:script location="classpath:/db.script" />
</jdbc:embedded-database>

<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
	<property name="dataSource" ref="empDS"/>
</bean>

<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
	<property name="dataSource" ref="empDS"/>
	<property name="typeAliasesPackage" value="net.learntechnology.empmaint.domain"/>
</bean>

<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
	<property name="basePackage" value="net.learntechnology.empmaint.mapper"/>
	<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
</bean>

Now you just make a Mapper interface and the mapper xml that holds the sql:

 public interface EmployeeMapper {
	List getAllEmployees();
	void updateEmployee(Employee emp);
	void deleteEmployee(Integer id);
	public Employee getEmployee(Integer id);
	public void insertEmployee(Employee emp);
 }

EmployeMapper.xml

PUBLIC "-//ibatis.apache.org//DTD Mapper 3.0//EN" "http://ibatis.apache.org/dtd/ibatis-3-mapper.dtd"> <mapper namespace="net.learntechnology.empmaint.mapper.EmployeeMapper"> <resultMap id="employeeResult" type="Employee"> <result property="id" column="id"/> <result property="firstName" column="firstname"/> <result property="lastName" column="lastname"/> <result property="age" column="age"/> <result property="department.id" column="departmentid"/> <result property="department.name" column="department_name"/> </resultMap> <select id="getAllEmployees" resultMap="employeeResult"> SELECT emp.id, emp.firstname, emp.lastname, emp.age, emp.departmentid, dep.name as department_name FROM employee emp JOIN department dep ON dep.id = emp.departmentid ORDER BY firstname, lastname </select> .....

Note above we didn't have to use a result map since the columns returned match our Employee object. You could map straight to the object type if you like (assuming your columns are aliased correctly to match your object properties):

No ResultMap needed:

	<select id="getAllEmployees" resultType="Employee">
		SELECT
			emp.id,
			emp.firstname,
			emp.lastname,
			emp.age,
			emp.departmentid,
			dep.name as department_name
		FROM employee emp
		JOIN department dep ON dep.id = emp.departmentid
		ORDER BY firstname, lastname
	</select>

To use our mapper we just declare it as a resource. SIMPLE!:

@Service
public class EmployeeServiceImpl implements EmployeeService {

	@Resource
	private EmployeeMapper employeeMapper;

	public List getAllEmployees() {
		return employeeMapper.getAllEmployees();
	}

     .....

Example service being used in a ZK ViewModel:

@Component("employeeVM")
@Scope("prototype")
public class EmployeeVM {
	 
	List<Employee> employees;

	@Resource
	private EmployeeService employeeService;

	@Init
	public void init() {
		employees = employeeService.getAllEmployees();
	}