SpringBoot入門Demo,一次深夜踩坑記錄。

springboot小專案開啟後，訪問埠無反應。

首先看我的專案目錄：

專案的pom檔案內容如下：

<?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.bes</groupId>
  <artifactId>spring-colud</artifactId>
  <version>1.0.0-SNAPSHOT</version>
  <modules>
    <module>user-service</module>
  </modules>
  <packaging>pom</packaging>

  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.0.4.RELEASE</version>
  </parent>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
    <spring-cloud.version>Finchley.SR1</spring-cloud.version>
    <mapper.starter.version>2.0.3</mapper.starter.version>
    <mysql.version>5.1.32</mysql.version>
    <pageHelper.starter.version>1.2.5</pageHelper.starter.version>
  </properties>

  <dependencyManagement>
    <dependencies>
      <!-- springcloud -->
      <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-dependencies</artifactId>
        <version>${spring-cloud.version}</version>
      </dependency>

      <!-- 通用Mapper啟動器 -->
      <dependency>
        <groupId>tk.mybatis</groupId>
        <artifactId>mapper-spring-boot-starter</artifactId>
        <version>${mapper.starter.version}</version>
      </dependency>

      <!-- 分頁助手啟動器 -->
      <dependency>
        <groupId>com.github.pagehelper</groupId>
        <artifactId>pagehelper-spring-boot-starter</artifactId>
        <version>${pageHelper.starter.version}</version>
      </dependency>

      <!-- mysql驅動 -->
      <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>${mysql.version}</version>
      </dependency>
    </dependencies>
  </dependencyManagement>

  <dependencies>
    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <version>1.18.4</version>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
      </plugin>
    </plugins>
  </build>

</project>

我的application.yml配置為：

server:
port: 8081
spring:
datasource:
url: jdbc:mysql://localhost:3306/springboot
username: root
password: root
mybatis:
type-aliases-package: com.bes.user.domain

UserDao為

package com.bes.user.dao;

import com.bes.user.domain.User;
import org.springframework.stereotype.Repository;
import tk.mybatis.mapper.common.Mapper;

public interface UserDao extends Mapper<User> {
}

UserService為：

package com.bes.user.service;

import com.bes.user.dao.UserDao;
import com.bes.user.domain.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

@Service
@Transactional
public class UserService {
  @Autowired
  UserDao userDao;

  public User findById(Integer id) {
    User user = userDao.selectByPrimaryKey(id);
    return user;
  }
}

UserController為：

package com.bes.user.web;

import com.bes.user.domain.User;
import com.bes.user.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/user")
public class UserController {
  @Autowired
  UserService userService;

  @GetMapping("{id}")
  public User findById(@PathVariable("id")Integer id) {
    User user = userService.findById(id);
    return user;
  }
}

UserApplication為：

package com.bes;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import tk.mybatis.spring.annotation.MapperScan;

@SpringBootApplication
@MapperScan("com.bes.user.dao")
public class UserApplication {
  public static void main(String[] args) {
    SpringApplication.run(UserApplication.class,args);
  }
}

上述程式碼是填坑之後的，而錯誤的原因也非常奇葩在UserService中自動注入UserDao時提示我沒有UserDao這個bean.

於是我就在UserDao上加了一個@Repository註解，如下圖：

而後UserService不在報錯了，執行UserApplication專案正常起來了。

但是通過瀏覽器訪問時卻一片空白。

這時在回到IDEA檢視下方日誌多了兩行東西。1111是我除錯時讓它列印的無關東西。

這個奇怪的錯誤搞了我幾個小時。最後發現不因給在UserDao上加@Reposity註解。UserService中注入Use人Dao報錯時應如下處理：

1、滑鼠點選報錯的UserService中報錯的UserDao

2、ALT+ENTER

3、選擇第一個選項

4、在選擇disable開頭的選項

問題解決。

以上這篇SpringBoot服務開啟後通過埠訪問無反應的解決就是小編分享給大家的全部內容了，希望能給大家一個參考，也希望大家多多支援我們。