spring mongodb学习

  spring mongodb目前是M3,需要配合的是spring 3.0.5及JDK 1.6下,下面举例子
说明:

1 启动一个mongodb数据库
    ./mongodb-xxxxxxx/bin/mongod --dbpath=/mongodb

2 例子中,把20个Person对象入mongodb数据库,算其平均年龄
  

@Document
public class Person {

    @Id
    private String personId;

    private String name;
    private String homeTown;
    private int age;

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getPersonId() {
        return personId;
    }

    public void setPersonId(final String personId) {
        this.personId = personId;
    }

    public String getName() {
        return name;
    }
    public void setName(final String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(final int age) {
        this.age = age;
    }

    public String getHomeTown() {
        return homeTown;
    }

    public void setHomeTown(final String homeTown) {
        this.homeTown = homeTown;
    }

    @Override
    public String toString() {
        return "Person [id=" + personId + ", name=" + name + ", age=" + age + ", home town=" + homeTown + "]";
    }

3 编写业务逻辑类,调用mongodb,代码如下:

@Repository
public class PersonRepository {

    static final Logger logger = LoggerFactory.getLogger(PersonRepository.class);

    @Autowired
    MongoTemplate mongoTemplate;

    public void logAllPersons() {
        List<Person> results = mongoTemplate.findAll(Person.class);
        logger.info("Total amount of persons: {}", results.size());
        logger.info("Results: {}", results);
    }

    /**
     * Calculates the average age of a {@link Person}.
     *
     * @return the average age
     */
    public int getAvarageAgeOfPerson() {
        List<Person> results = mongoTemplate.findAll(Person.class);
        int age = 0;
        Iterator<Person> personIterator = results.iterator();
        while (personIterator.hasNext()) {
            Person nextPerson = personIterator.next();
            age += nextPerson.getAge();
        }
        return age / results.size();
    }

    public void insertPersonWithNameJohnAndRandomAge() {
        //get random age between 1 and 100
        double age = Math.ceil(Math.random() * 100);

        Person p = new Person("John", (int) age);

        mongoTemplate.insert(p);
    }

    /**
     * Create a {@link Person} collection if the collection does not already exists
     */
    public void createPersonCollection() {
        if (!mongoTemplate.collectionExists(Person.class)) {
            mongoTemplate.createCollection(Person.class);
        }
    }

    /**
     * Drops the {@link Person} collection if the collection does already exists
     */
    public void dropPersonCollection() {
        if (mongoTemplate.collectionExists(Person.class)) {
            mongoTemplate.dropCollection(Person.class);
        }
    }

4 配置spring配置文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-3.0.xsd">

  <!-- Activate annotation configured components -->
  <context:annotation-config/>

  <!-- Scan components for annotations within the configured package -->
  <context:component-scan base-package="com.jeroenreijn.mongodb.example">
    <context:exclude-filter type="annotation" expression="org.springframework.context.annotation.Configuration"/>
  </context:component-scan>

  <!-- Define the MongoTemplate which handles connectivity with MongoDB -->
  <bean id="mongoTemplate" class="org.springframework.data.document.mongodb.MongoTemplate">
    <constructor-arg name="mongo" ref="mongo"/>
    <constructor-arg name="databaseName" value="mongodb

"/>
  </bean>

  <!-- Factory bean that creates the Mongo instance -->
  <bean id="mongo" class="org.springframework.data.document.mongodb.MongoFactoryBean">
    <property name="host" value="localhost"/>
  </bean>

  <!-- Use this post processor to translate any MongoExceptions thrown in @Repository annotated classes -->
  <bean class="org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor"/>

</beans>

5 最后启动的主类

public class MongoDBApp {

    static final Logger logger = LoggerFactory.getLogger(MongoDBApp.class);

    public static void main( String[] args ) {
        logger.info("Bootstrapping MongoDemo application");

        ConfigurableApplicationContext context = new ClassPathXmlApplicationContext("META-INF/spring/applicationContext.xml");

        PersonRepository personRepository = context.getBean(PersonRepository.class);

        // cleanup person collection before insertion
        personRepository.dropPersonCollection();

        //create person collection
        personRepository.createPersonCollection();

        for(int i=0; i<20; i++) {
            personRepository.insertPersonWithNameJohnAndRandomAge();
        }

        personRepository.logAllPersons();
        logger.info("Avarage age of a person is: {}", personRepository.getAvarageAgeOfPerson());

        logger.info("Finished MongoDemo application");
    }