JDBC Template in Spring giving exception

Question

So I have tried many changes and what not, but I am not sure what the heck is going wrong with my code. This is my first project in Spring. I am being given a null pointer exception with my sql methods.

My JdbcDAO.java

import javax.sql.DataSource;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.support.JdbcDaoSupport;
import org.springframework.jdbc.datasource.*;
import org.springframework.stereotype.Repository;

/**
 * Created by Albedo on 6/6/2017.
 */

@Repository("reviewDAO")
public class JdbcReviewDAO {
    private DataSource dataSource;
    private JdbcTemplate jdbcTemplate;

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

    @Bean
    public JdbcTemplate getTemplate(){
        return jdbcTemplate;
    }

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

    // sql methods go here
}

My spring-Datasource.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

    <bean id="dataSource"
          class="org.springframework.jdbc.datasource.DriverManagerDataSource">

        <property name="driverClassName" value="com.mysql.jdbc.Driver" />
        <property name="url" value="jdbc:mysql://127.0.0.1:3306/" />
        <property name="username" value="root" />
        <property name="password" value="admin" />
                </bean>
 <bean id="reviewDAO" class="com.JdbcReviewDAO">
    <property name="dataSource" ref="dataSource" />
</bean>
</beans>

My application.java:

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

@SpringBootApplication
public class Application {

    public static void main(String[] args) {
        //ApplicationContext context =
        //      new ClassPathXmlApplicationContext("Spring-Review.xml");
        JdbcReviewDAO reviewDAO = new JdbcReviewDAO();
        reviewDAO.grabFirstPost(1);
        SpringApplication.run(Application.class, args);
    }
}

(I have removed package names - rest assured they are properly defined in the project. As well with SQL methods to remove redundancy. Let me know if I should include them if you suspect they are the problem.) I think this is more an 'infrastructure' issue(forgive my ignorance, still a noobie) rather than code. Anyone have an idea?

Error log: \

Exception in thread "main" java.lang.NullPointerException
    at JdbcDAO.grabFirstPost(JdbcDAO.java:63)
    at Application.main(Application.java:15)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)

Process finished with exit code 1

Method* that gives the error:

public String grabFirstPost(int id) {
    String sql = "SELECT * FROM post WHERE postid ='" + id + "'";

    String postContent = (String)jdbcTemplate.queryForObject(sql, new Object[] {id}, String.class);
    return postContent;
}

Answer 1

Your main method is wrong. You are not loading application context but directly creating your DAO. Maybe you need to change to this:

ApplicationContext context =
      new ClassPathXmlApplicationContext("Spring-Review.xml");
JdbcReviewDAO reviewDAO = context.getBean("reviewDAO");

Answer 2

Looks like the variable jdbcTemplate contains null. The most likely cause is that Spring does not inject it, because the setter is not annotated with @Autowired.