利用Morphia框架工具类操作mongodb的实例。

译自：http://mongodb.github.io/morphia/1.2/getting-started/quick-tour/

实例类：QuickTour.java的代码如下：

package example;

import com.mongodb.MongoClient;

import org.bson.types.ObjectId;

import org.junit.Assert;

import org.mongodb.morphia.Datastore;

import org.mongodb.morphia.Morphia;

import org.mongodb.morphia.annotations.Entity;

import org.mongodb.morphia.annotations.Field;

import org.mongodb.morphia.annotations.Id;

import org.mongodb.morphia.annotations.Index;

import org.mongodb.morphia.annotations.Indexes;

import org.mongodb.morphia.annotations.Property;

import org.mongodb.morphia.annotations.Reference;

import org.mongodb.morphia.query.Query;

import org.mongodb.morphia.query.UpdateOperations;

import org.mongodb.morphia.query.UpdateResults;

import java.net.UnknownHostException;

import java.util.ArrayList;

import java.util.List;

/**

 * This class is used in the Quick Tour documentation and is used to demonstrate various Morphia features.

 */

public final class QuickTour {

    private QuickTour() {

    }

    public static void main(final String[] args) throws UnknownHostException {

        final Morphia morphia = new Morphia();

        // tell morphia where to find your classes

        // can be called multiple times with different packages or classes

        morphia.mapPackage("org.mongodb.morphia.example");

        // create the Datastore connecting to the database running on the default port on the local host

        //morphia_example为数据库名

        final Datastore datastore = morphia.createDatastore(new MongoClient(), "morphia_example");

        datastore.getDB().dropDatabase();

        datastore.ensureIndexes();

        final Employee elmer = new Employee("Elmer Fudd", 50000.0);

        //在数据库中保存该实体类的内容到对应的集合（collection）中

        datastore.save(elmer);

        final Employee daffy = new Employee("Daffy Duck", 40000.0);

        datastore.save(daffy);

        final Employee pepe = new Employee("Pepé Le Pew", 25000.0);

        datastore.save(pepe);

        

        //在elmer的directReports属性中添加元素（内嵌属性）

        elmer.getDirectReports().add(daffy);

        elmer.getDirectReports().add(pepe);

        datastore.save(elmer);

        Query<Employee> query = datastore.createQuery(Employee.class);

        final List<Employee> employees = query.asList();

        //利用junit的Assert工具类判断employees.size()是否等于3，不等的话程序将抛出异常。

        Assert.assertEquals(3, employees.size());

        List<Employee> underpaid = datastore.createQuery(Employee.class)

                                            .filter("salary <=", 30000)

                                            .asList();

        Assert.assertEquals(1, underpaid.size());

        underpaid = datastore.createQuery(Employee.class)

                             .field("salary").lessThanOrEq(30000)

                             .asList();

        Assert.assertEquals(1, underpaid.size());

        final Query<Employee> underPaidQuery = datastore.createQuery(Employee.class)

                                                        .filter("salary <=", 30000);

        final UpdateOperations<Employee> updateOperations = datastore.createUpdateOperations(Employee.class)

                                                                     .inc("salary", 10000);

        // salary <= 30000 的文档（document）（行）的salary增加 10000

        final UpdateResults results = datastore.update(underPaidQuery, updateOperations);

        Assert.assertEquals(1, results.getUpdatedCount());

        final Query<Employee> overPaidQuery = datastore.createQuery(Employee.class)

                                                       .filter("salary >", 100000);

        //实际没有删除任何数据

        datastore.delete(overPaidQuery);

    }

}

//employees为该实体类对应的该数据库的集合名称（表名）

@Entity("employees")

//索引相关

@Indexes(@Index(value = "salary", fields = @Field("salary")))

class Employee {

    @Id

    private ObjectId id;

    private String name;

    private Integer age;

    @Reference

    private Employee manager;

    @Reference

    private List<Employee> directReports = new ArrayList<Employee>();

    //属性salary对应集合employees中的wage域名（字段名）

    @Property("wage")

    private Double salary;

    public Employee() {

    }

    public Employee(final String name, final Double salary) {

        this.name = name;

        this.salary = salary;

    }

    public List<Employee> getDirectReports() {

        return directReports;

    }

    public void setDirectReports(final List<Employee> directReports) {

        this.directReports = directReports;

    }

    public ObjectId getId() {

        return id;

    }

    public Employee getManager() {

        return manager;

    }

    public void setManager(final Employee manager) {

        this.manager = manager;

    }

    public String getName() {

        return name;

    }

    public void setName(final String name) {

        this.name = name;

    }

    public Double getSalary() {

        return salary;

    }

    public void setSalary(final Double salary) {

        this.salary = salary;

    }

}

pom.xml文件定义如下：

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion>
<groupId>test-group</groupId>
<artifactId>test-artifact</artifactId>
<packaging>jar</packaging>
<version>0.0.1-SNAPSHOT</version>
<name>test-artifact Maven Webapp</name>
<url>http://maven.apache.org</url>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<!-- <scope>test</scope> -->
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<!-- <scope>test</scope> -->
</dependency>
<dependency>
<groupId>net.sf.json-lib</groupId>
<artifactId>json-lib</artifactId>
<version>2.4</version>
<classifier>jdk15</classifier>
</dependency>

<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.6.2</version>
</dependency>

<!-- <dependency> <groupId>net.sf.json-lib</groupId> <artifactId>json-lib</artifactId> 
<version>2.4</version> </dependency> -->
<dependency>
<groupId>javax.mail</groupId>
<artifactId>javax.mail-api</artifactId>
<version>1.5.5</version>
</dependency>

<dependency>
<groupId>javax.activation</groupId>
<artifactId>activation</artifactId>
<version>1.1.1</version>
</dependency>

<dependency>
<groupId>javax.mail</groupId>
<artifactId>mail</artifactId>
<version>1.4.7</version>
</dependency>

<dependency>
<groupId>org.mongodb.morphia</groupId>
<artifactId>morphia</artifactId>
<version>1.2.0</version>
</dependency>

<dependency>
<groupId>org.mongodb</groupId>
<artifactId>mongo-java-driver</artifactId>
<version>3.2.2</version>
</dependency>

</dependencies>
<build>
<finalName>test-artifact</finalName>
</build>

</project>