Spring Boot学习(八)之使用NoSQL数据库（二）：MongDb_spring boot 创建的mongdb数据库在nosqlbooster中没有显示

Spring Boot中可以通过在pom.xml中加入spring-boot-starter-data-mongodb引入对mongodb的访问支持依赖。它的实现依赖spring-data-mongodb。是的，您没有看错，又是spring-data的子项目，之前介绍过spring-data-jpa、spring-data-redis，对于mongodb的访问，spring-data也提供了强大的支持，下面就开始动手试试吧。

<?xml version="1.0" encoding="UTF-8"?>
<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/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
 
   <groupId>com.xiaojingg</groupId>
   <artifactId>springbootstudy-demo8-mongdb</artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <packaging>jar</packaging>
   <name>springbootstudy-demo8-mongdb</name>
   <description>Demo project for Spring Boot</description>
   <parent>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-parent</artifactId>
      <version>1.5.8.RELEASE</version>
      <relativePath/> <!-- lookup parent from repository -->
   </parent>
   <properties>
      <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
      <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
      <java.version>1.8</java.version>
   </properties>
   <dependencies>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter</artifactId>
      </dependency>
 
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-test</artifactId>
         <scope>test</scope>
      </dependency>
 
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-data-mongodb</artifactId>
      </dependency>
   </dependencies>
   <build>
      <plugins>
         <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
         </plugin>
      </plugins>
   </build>
</project>

• 创建要存储的User实体，包含属性：id、username、age

package com.xiaojingg.domain;
 
import org.springframework.data.annotation.Id;
 
/**
 * xiaojingg
 */
public class User {
 
    @Id
    private Long id;
 
    private String username;
    private Integer age;
 
    public User(Long id, String username, Integer age) {
        this.id = id;
        this.username = username;
        this.age = age;
    }
 
    public Long getId() {
        return id;
    }
 
    public void setId(Long id) {
        this.id = id;
    }
 
    public String getUsername() {
        return username;
    }
 
    public void setUsername(String username) {
        this.username = username;
    }
 
    public Integer getAge() {
        return age;
    }
 
    public void setAge(Integer age) {
        this.age = age;
    }
}

• 实现User的数据访问对象：UserRepository

package com.xiaojingg.domain;
 
import org.springframework.data.mongodb.repository.MongoRepository;
 
/**
 * 筱进GG
 */
public interface UserRepository extends MongoRepository<User, Long> {
 
    User findByUsername(String username);
 
}

• 在单元测试中调用

package com.xiaojingg;
 
import com.xiaojingg.domain.User;
import com.xiaojingg.domain.UserRepository;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
 
@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringbootstudyDemo8MongdbApplicationTests {
 
   @Autowired
   private UserRepository userRepository;
 
   @Before
   public void setUp() {
      userRepository.deleteAll();
   }
 
   @Test
   public void test() throws Exception {
 
      // 创建三个User，并验证User总数
      userRepository.save(new User(1L, "keke", 30));
      userRepository.save(new User(2L, "GG", 40));
      userRepository.save(new User(3L, "QQ", 50));
      System.out.print("三个User:" + userRepository.findAll().size() + "\n");
 
      // 删除一个User，再验证User总数
      User u = userRepository.findOne(1L);
      userRepository.delete(u);
      System.out.print("删除一个User:" + userRepository.findAll().size() + "\n");
 
      // 删除一个User，再验证User总数
      u = userRepository.findByUsername("GG");
      userRepository.delete(u);
      System.out.print("删除一个User:" + userRepository.findAll().size() + "\n");
 
   }
}