利用Morphia框架工具類操作mongodb的例項。
譯自：http://mongodb.github.io/morphia/1.2/getting-started/quick-tour/
例項類：QuickTour.java的程式碼如下：
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為資料庫名
final Datastore datastore = morphia.createDatastore(new MongoClient(), "morphia_example");
datastore.getDB().dropDatabase();
datastore.ensureIndexes();
final Employee elmer = new Employee("Elmer Fudd", 50000.0);
//在資料庫中儲存該實體類的內容到對應的集合（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屬性中新增元素（內嵌屬性）
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工具類判斷employees.size()是否等於3，不等的話程式將丟擲異常。
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 的文件（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);
//實際沒有刪除任何資料
datastore.delete(overPaidQuery);
}
}
//employees為該實體類對應的該資料庫的集合名稱（表名）
@Entity("employees")
//索引相關
@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>();
//屬性salary對應集合employees中的wage域名（欄位名）
@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檔案定義如下：
<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>