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>

</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>

</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>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>

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利用Morphia框架工具类操作mongodb的实例。

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