Question

I’m having some trouble getting a data source bean, defined in an xml file, into a class in Spring using @Autowired annotation.

Would anyone have an idea what’s happening here? It seems as though dataSource in the *Impl class is not being wired in.

dao-context.xml

<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
    <property name="driverClassName" value="com.mysql.jdbc.Driver" />
    <property name="url" value="jdbc:mysql://localhost:8889/spring" />
    <property name="username" value="user" />
    <property name="password" value="1234" />
</bean>

PersonDaoImpl.java

public class PersonDaoImpl implements PersonDao {

@Autowired
private DataSource dataSource;  
private JdbcTemplate jdbcTemplate = new JdbcTemplate();


public DataSource getDataSource() {
    return dataSource;
}

public void setDataSource(DataSource dataSource) {
    System.out.println("SETTING DATA SOURCE");
    this.dataSource = dataSource;
}

public List<Person> getPersonList() {
    // TODO Auto-generated method stub
    return null;
}

public void savePerson(Person person) {
    // TODO Auto-generated method stub

}

public Person getPersonById(int id) {
    System.out.println("Getting Person: " + id);        
    return null;
}

@Override
public int getPersonCount(){
    String sql = "SELCECT COUNT(*) FROM PERSON";
    jdbcTemplate.setDataSource(getDataSource());
    int count = jdbcTemplate.queryForInt(sql);
    System.out.println("Count of Person: " + count);
    return count;
}

public JdbcTemplate getJdbcTemplate() {
    return jdbcTemplate;
}

public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
    this.jdbcTemplate = jdbcTemplate;
}

}

…and finally, the exception.

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.IllegalArgumentException: No DataSource specified
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:894)
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

java.lang.IllegalArgumentException: No DataSource specified
    org.springframework.util.Assert.notNull(Assert.java:112)
    org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:97)
    org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:77)
    org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:382)
    org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:456)
    org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:464)
    org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:472)
    org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:477)
    org.springframework.jdbc.core.JdbcTemplate.queryForInt(JdbcTemplate.java:486)
    com.myPackage.rest.dao.impl.PersonDaoImpl.getPersonCount(PersonDaoImpl.java:50)
    com.myPackage.rest.HomeController.home(HomeController.java:36)
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    java.lang.reflect.Method.invoke(Method.java:597)
    org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:212)
    org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:126)
    org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:96)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:617)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:578)
    org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:900)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:827)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

Any help would be greatly appreciated, cheers.

Answer 1

Your data source needs to be set in the JdbcTemplate (I don’t see you doing that). Also since you put the @Autowired annotation on the field, I don’t think it uses the setter so that would be why your setDataSource method is not being called. Since your exception indicates that you called jdbcTemplate.execute and dataSource is null, this makes sense.

If you look here: http://static.springsource.org/spring/docs/current/spring-framework-reference/html/jdbc.html there is an example of autowiring a data source, but the idea is:

public class  MyDao {

    private JdbcTemplate jdbcTemplate;

    @Autowired
    public void setDataSource(DataSource dataSource) {
        this.jdbcTemplate = new JdbcTemplate(dataSource);
    }
}