13.6 SpringBoot集成Mongodb開發(fā)問題@EnableMongoRepositories路徑配置

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APPLICATION FAILED TO START

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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'.

代碼

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:* 這里要使用@Controller注解* 而不要使用@RestController* 否則return "index";只是返回字符串"index"， 不能跳轉(zhuǎn)到index.html** @RestController is a stereotype annotation that combines @ResponseBody and @Controller.* @RestController注解相當于@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極簡教程", "XXX", "JasonChen", now, now, 0, now, "", 0))blogService.save(Blog("SpringBoot極簡教程", "XXX", "BluceLi", now, now, 0, now, "", 0))blogService.save(Blog("SpringBoot極簡教程", "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路徑配置問題，AbstractMongoConfiguration掃描dao層包路徑的配置要細心。

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" // }/*** 這地方是配置掃描繼承Repository類的所有接口類的路徑的，路徑配置錯誤，bean就不會創(chuàng)建了。* 東海陳光劍 Jason Chen @蔣村花園如意苑 2017.3.30 01:41:35*/override fun getMappingBasePackages(): Collection<String> {return setOf("com.restfeel.dao", "com.restfeel.service")} }

原理

比如說，有代碼

@Autowired private UserDao userDao;

其中UserDao來自

public interface UserDao extends CrudRepository<User, Long>

無論在哪兒也找不到這個Bean是在哪兒定義的，但是代碼還能正常工作。@Autowired 默認找不到會報錯，再不然就是null，不會創(chuàng)建bean。

我們正常會推測：這是 CrudRepository導致的， CrudRepository會自動創(chuàng)建一個Bean。事實如此，這個是spring data jpa的功能，它會掃描Repository的子類并實現(xiàn)它們。

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