13.6 SpringBoot集成Mongodb开发问题@EnableMongoRepositories路径配置

APPLICATION FAILED TO START

Description:

Parameter 0 of constructor in com.restfeel.controller.BlogController required a bean of type 'com.restfeel.biz.BlogService' that could not be found.

Action:

Consider defining a bean of type 'com.restfeel.biz.BlogService' in your configuration.

:bootRun FAILED

FAILURE: Build failed with an exception.

• What went wrong:
  Execution failed for task ':bootRun'.

代码

package com.restfeel.serviceimport com.restfeel.entity.Blog
import org.springframework.data.mongodb.repository.MongoRepository
import org.springframework.data.mongodb.repository.Query
import org.springframework.data.repository.query.Paraminterface BlogService : MongoRepository<Blog, String> {@Query("{ 'title' : ?0 }")fun findByTitle(@Param("title") title: String): Iterable<Blog>}package com.restfeel.controllerimport com.restfeel.service.BlogService
import com.restfeel.entity.Blog
import org.springframework.boot.autoconfigure.EnableAutoConfiguration
import org.springframework.context.annotation.ComponentScan
import org.springframework.stereotype.Controller
import org.springframework.transaction.annotation.Propagation
import org.springframework.transaction.annotation.Transactional
import org.springframework.ui.Model
import org.springframework.web.bind.annotation.GetMapping
import org.springframework.web.bind.annotation.RequestParam
import org.springframework.web.bind.annotation.ResponseBody
import java.util.*/*** * 注意:*      这里要使用@Controller注解*      而不要使用@RestController*      否则return "index";只是返回字符串"index"， 不能跳转到index.html**      @RestController is a stereotype annotation that combines @ResponseBody and @Controller.*      @RestController注解相当于@ResponseBody ＋ @Controller合在一起的作用。*/@Controller
@EnableAutoConfiguration
@ComponentScan
@Transactional(propagation = Propagation.REQUIRES_NEW)
class BlogController(val blogService: BlogService) {@GetMapping("/blogs.do")fun listAll(model: Model): String {val now = Date();blogService.save(Blog("SpringBoot极简教程", "XXX", "JasonChen", now, now, 0, now, "", 0))blogService.save(Blog("SpringBoot极简教程", "XXX", "BluceLi", now, now, 0, now, "", 0))blogService.save(Blog("SpringBoot极简教程", "XXX", "MichelleChen", now, now, 0, now, "", 0))val allblogs = blogService.findAll()model.addAttribute("blogs", allblogs)return "jsp/blog/list"}@GetMapping("/listblogs")@ResponseBodyfun listblogs(model: Model) = blogService.findAll()@GetMapping("/findBlog")@ResponseBodyfun findBlog(@RequestParam(value = "title") title: String) = blogService.findByTitle(title)}

原因

@EnableMongoRepositories路径配置问题，AbstractMongoConfiguration扫描dao层包路径的配置要细心。

package com.restfeel.configimport com.mongodb.Mongo
import com.mongodb.MongoClient
import com.mongodb.MongoCredential
import com.mongodb.ServerAddress
import org.springframework.beans.factory.annotation.Autowired
import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.Configuration
import org.springframework.core.env.Environment
import org.springframework.data.mongodb.config.AbstractMongoConfiguration
import org.springframework.data.mongodb.repository.config.EnableMongoRepositories/*** Created by jack on 2017/3/29.*/@Configuration
@EnableMongoRepositories(*arrayOf("com.restfeel.dao", "com.???.???"))
class PersistenceConfig : AbstractMongoConfiguration() {@Autowiredprivate val env: Environment? = nulloverride fun getDatabaseName(): String {return env!!.getProperty("mongodb.name")}@Bean@Throws(Exception::class)override fun mongo(): Mongo {return MongoClient(listOf(ServerAddress(env!!.getProperty("mongodb.host"), env!!.getProperty("mongodb.port", Int::class.java))),listOf(MongoCredential.createCredential(env!!.getProperty("mongodb.username"), env!!.getProperty("mongodb.name"),env!!.getProperty("mongodb.password").toCharArray())))}//    override fun getMappingBasePackage(): String {
//        return "com.restfiddle.dao"
//    }/*** 这地方是配置扫描继承Repository类的所有接口类的路径的，路径配置错误，bean就不会创建了。* 东海陈光剑 Jason Chen @蒋村花园如意苑 2017.3.30 01:41:35*/override fun getMappingBasePackages(): Collection<String> {return setOf("com.restfeel.dao", "com.restfeel.service")}
}

原理

比如说，有代码

@Autowired
private UserDao userDao;

其中UserDao来自

public interface UserDao extends CrudRepository<User, Long>

无论在哪儿也找不到这个Bean是在哪儿定义的，但是代码还能正常工作。@Autowired 默认找不到会报错，再不然就是null，不会创建bean。

我们正常会推测：这是 CrudRepository导致的， CrudRepository会自动创建一个Bean。事实如此，这个是spring data jpa的功能，它会扫描Repository的子类并实现它们。