資訊專欄INFORMATION COLUMN
摘要：每個條件必須引用一個屬性，并且還可以指定一種比較操作。如果省略比較操作符的話，那么這暗指是一種相等比較操作。
Spring-data對MongoDB進行了很好的支持，接下來就講解一下關于Spring對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構建
具體的工程代碼大家可以訪問我的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
// 啟用MongoDB的Repository功能，會對其Repositories自動掃描
@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});
//還可以對端口進行配置
return mongo;
}
// Mongo Template配置
@Bean
public MongoOperations mongoTemplate(Mongo mongo) {
//OrdersDB就是Mongo的數據庫
return new MongoTemplate(mongo, "OrdersDB");
}
}
為了訪問數據庫的時候，我們可能還需要帳號密碼
MongoCredential credential=MongoCredential.createCredential(env.getProperty("mongo.username"), "OrdersDB",env.getProperty("mongo.password").toCharArray());
mongo.setCredentials(new MongoCredential[]{credential});
②為模型添加注解
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;
//這是文檔
@Document
public class Order {
//指定ID
@Id
private String id;
//為域重命名
@Field("client")
private String customer;
private String type;
private Collection- items=new LinkedHashSet
- ();
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
- getItems() {
return items;
}
public void setItems(Collection
- 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;
}
}
| 注解 | 描述 |
|---|---|
| @Document | 標示映射到mongoDB文檔上的領域對象 |
| @ID | 標示某個為ID域 |
| @DbRef | 標示某個域要引用其他的文檔，這個文檔有可能位于另外一個數據庫中 |
| @Field | 為文檔域指定自定義的元數據 |
| @Version | 標示某個屬性用作版本域 |
③使用MongoTemplate訪問MongoDB若不使用@Field注解，域名就與Java屬性相同
上面之所以Item的Java類為什么沒有@Document注解，是因為我們不會多帶帶想Item持久化為文檔
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");
//第二個參數是文檔存儲的名稱
// mongo.save(order,"order");
// String orderId="1";
// Order order=mongo.findById(orderId, Order.class);
// System.out.println(order.getCustomer());
return "index";
}
}
在這里我們將MongoTemplate注入到一個類型為MongoOperations的屬性中。MongoOperations是MongoTemplate所實現的接口，MongoOperations中存在很多文檔操作方法
MongoOperations其實已經能滿足很多需求了
如果還沒有滿足你的需求，接下來我就介紹一下，如何編寫MongoDB Repository
編寫MongoDB Repository
