Spring-data对MongoDB进行了很好的支持，接下来就讲解一下关于Spring对MongoDB的配置和一些正常的使用

我下面的工程使用的是Spring的Java配置的方式和Maven构建

具体的工程代码大家可以访问我的Github地址:https://github.com/zoeminghong/springmvc-javaconfig

①MongoDB的必要配置

package springmvc.rootconfig;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.mongodb.core.MongoClientFactoryBean;
import org.springframework.data.mongodb.core.MongoOperations;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.repository.config.EnableMongoRepositories;

import com.mongodb.Mongo;

@Configuration
// 启用MongoDB的Repository功能，会对其Repositories自动扫描
@EnableMongoRepositories(basePackages = "springmvc.orders.db")    
public class MongoConfig {
    // MongoClient配置
    @Bean
    public MongoClientFactoryBean mongo() {
        MongoClientFactoryBean mongo = new MongoClientFactoryBean();
        mongo.setHost("localhost");
      //MongoCredential credential=MongoCredential.createCredential(env.getProperty("mongo.username"), "OrdersDB",env.getProperty("mongo.password").toCharArray());
//        mongo.setCredentials(new MongoCredential[]{credential});
        //还可以对端口进行配置
        return mongo;
    }

    // Mongo Template配置
    @Bean
    public MongoOperations mongoTemplate(Mongo mongo) {
        //OrdersDB就是Mongo的数据库
        return new MongoTemplate(mongo, "OrdersDB");
    }
}

为了访问数据库的时候，我们可能还需要帐号密码

MongoCredential credential=MongoCredential.createCredential(env.getProperty("mongo.username"), "OrdersDB",env.getProperty("mongo.password").toCharArray());
mongo.setCredentials(new MongoCredential[]{credential});

②为模型添加注解

package springmvc.bean;

import java.util.Collection;
import java.util.LinkedHashSet;

import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.mapping.Document;
import org.springframework.data.mongodb.core.mapping.Field;
//这是文档
@Document
public class Order {
  //指定ID
    @Id
    private String id;
    //为域重命名
    @Field("client")
    private String customer;
    private String type;
     private Collection<Item> items=new LinkedHashSet<Item>();
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public String getCustomer() {
        return customer;
    }
    public void setCustomer(String customer) {
        this.customer = customer;
    }
    public String getType() {
        return type;
    }
    public void setType(String type) {
        this.type = type;
    }
    public Collection<Item> getItems() {
        return items;
    }
    public void setItems(Collection<Item> items) {
        this.items = items;
    }
    
}

package springmvc.bean;

public class Item {

    private Long id;
    private Order order;
    private String product;
    private double price;
    private int quantity;
    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    public Order getOrder() {
        return order;
    }
    public void setOrder(Order order) {
        this.order = order;
    }
    public String getProduct() {
        return product;
    }
    public void setProduct(String product) {
        this.product = product;
    }
    public double getPrice() {
        return price;
    }
    public void setPrice(double price) {
        this.price = price;
    }
    public int getQuantity() {
        return quantity;
    }
    public void setQuantity(int quantity) {
        this.quantity = quantity;
    }
    
}

若不使用@Field注解，域名就与Java属性相同

上面之所以Item的Java类为什么没有@Document注解，是因为我们不会单独想Item持久化为文档

③使用MongoTemplate访问MongoDB

package springmvc.web;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.mongodb.core.MongoOperations;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import springmvc.bean.Order;
import springmvc.orders.db.OrderRepository;

@Controller
public class HomeController {
    @Autowired
    MongoOperations mongo;

    @RequestMapping(value = { "/", "index" }, method = RequestMethod.GET)
    public String index() {
         long orderCount=mongo.getCollection("order").count();
         System.out.println(orderCount);
//        Order order = new Order();
//        order.setId("1");
//        order.setCustomer("gg");
//        order.setType("2");
      //第二个参数是文档存储的名称
//        mongo.save(order,"order");
//        String orderId="1";
//        Order order=mongo.findById(orderId, Order.class);
//        System.out.println(order.getCustomer());
        return "index";
    }
}

在这里我们将MongoTemplate注入到一个类型为MongoOperations的属性中。MongoOperations是MongoTemplate所实现的接口，MongoOperations中存在很多文档操作方法

MongoOperations其实已经能满足很多需求了

如果还没有满足你的需求，接下来我就介绍一下，如何编写MongoDB Repository

编写MongoDB Repository

package springmvc.orders.db;

import java.util.List;

import org.springframework.data.mongodb.repository.MongoRepository;

import springmvc.bean.Order;

public interface OrderRepository extends MongoRepository<Order, String> {
    List<Order> findByCustomer(String c);

    List<Order> findByCustomerLike(String c);

    List<Order> findByCustomerAndType(String c, String t);

    List<Order> findByCustomerLikeAndType(String c, String t);
}

看到这里，大家有没有发现package的地址就是我们刚才@EnableMongoRepositories(basePackages = “springmvc.orders.db”)的配置

MongoRepository接口有两个参数，第一个是带有@Document注解的对象类型，也就是该Repository要处理的类型。第二个参数是带有@Id注解的属性类型

OrderRepository继承了MongoRepository中很多自带的方法

上面的我们定义的四个方法都是我们自定义的方法，其方法名存在很多意义，不能随便定义

List<Order> findByCustomer(String c);

find为查询动词，还可以是read、get、count等

Customer为断言，判断其行为

在断言中，会有一个或多个限制结果的条件。每个条件必须引用一个属性，并且还可以指定一种比较操作。如果省略比较操作符的话，那么这暗指是一种相等比较操作。不过，我们也可以选择其他的比较操作

other

指定查询

@Query("{'customer':'Chuck Wagon','type':?0}")
List<Order> findChucksOrders(String t);

@Query中给定的JSON将会与所有的Order文档进行匹配，并返回匹配的文档，这里的type属性映射成“？0”，这表明type属性应该与查询方法的第0个参数相等，如果有多个参数，则”?1″…..

混合自定义的功能

package springmvc.orders.db;

import java.util.List;

import springmvc.bean.Order;

public interface OrderOperations {
    List<Order> findOrdersByType(String t);

}

package springmvc.orders.db;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.mongodb.core.MongoOperations;
import org.springframework.data.mongodb.core.query.Criteria;
import org.springframework.data.mongodb.core.query.Query;

import springmvc.bean.Order;

public class OrderRepositoryImpl implements OrderOperations {
    @Autowired
    private MongoOperations mongo;
    //将混合实现注入MongoOperations
    @Override
    public List<Order> findOrdersByType(String t) {
        String type =t.equals("Net")?"2":t;
        Criteria where=Criteria.where("type").is(type);
        Query query=Query.query(where);
        return mongo.find(query, Order.class);
    }
}

package springmvc.orders.db;

import java.util.List;

import org.springframework.data.mongodb.repository.MongoRepository;
import org.springframework.data.mongodb.repository.Query;

import springmvc.bean.Order;
//继承OrderOperations接口
public interface OrderRepository extends MongoRepository<Order, String>,OrderOperations {
    List<Order> findByCustomer(String c);

    List<Order> findByCustomerLike(String c);

    List<Order> findByCustomerAndType(String c, String t);

    List<Order> findByCustomerLikeAndType(String c, String t);
    
    @Query("{'customer':'Chuck Wagon','type':?0}")
    List<Order> findChucksOrders(String t);
    
}

package springmvc.web;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.mongodb.core.MongoOperations;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import springmvc.bean.Order;
import springmvc.orders.db.OrderRepository;

@Controller
public class HomeController {
    @Autowired
    MongoOperations mongo;
    @Autowired
    OrderRepository orderRepository;

    @RequestMapping(value = { "/", "index" }, method = RequestMethod.GET)
    public String index() {
        List<Order> list=orderRepository.findOrdersByType("2");
        System.out.println(list.size());
        return "index";
    }
}

以上这些关联起来的关键点是OrderRepositoryImpl，这个名字前半部分与OrderRepository相同，只是添加了一个“Impl”后缀。如果想更改该后缀，可以在MongoConfig类中更改为自己理想的后缀

@EnableMongoRepositories(basePackages = "springmvc.orders.db",repositoryImplementationPostfix="Stuff")    

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