一、创建项目
1.File->new->project;
2.选择“Spring Initializr”,点击next;(jdk1.8默认即可)
3.完善项目信息,组名可不做修改,项目名可做修改;最终建的项目名为:test,src->main->java下包名会是:com->example->test;点击next;
4.Web下勾选Spring Web Start,(网上创建springboot项目多是勾选Web选项,而较高版本的Springboot没有此选项,勾选Spring Web Start即可,2.1.8版本是Spring Web);Template Englines勾选Thymeleaf;SQL勾选:MySQL Driver,JDBC API 和 MyBatis Framework三项;点击next;
5.选择项目路径,点击finish;打开新的窗口;
6.刚创建好的项目目录结构
7.点击右侧的Maven,点击设置(扳手图标)进行项目Maven仓库的配置;
8.(1)选择本地Maven路径;(2)勾选配置文件后边的选项,然后修改为本地Maven的配置文件,它会根据配置文件直接找到本地仓库位置;
9.配置完后,如果没有自动导包,可以点击左上角重新导包按钮,或者呢个下载按钮,选择下载所有源文件和文档
10.在templates文件下新建index.html页面,作为启动的初始页面;
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>hello</title> </head> <body> 你好!初学者,我是SpringBoot的简单启动页面! </body> </html>
11.在com.example.test下新建controller文件夹,在controller文件夹下建一个简单的helloController类;(Controller类要添加@Controller注解,项目启动时,SpringBoot会自动扫描加载Controller)
package com.example.test.controller; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; @Controller public class HelloController { @RequestMapping("/index") public String sayHello(){ return "index"; } }
12.在resources文件夹下application中先配置DataSource基本信息,application文件有两种文件格式,一种是以.properties为后缀,一种是以.yml为后缀的,两种配置方式略有差别,详情可参考这个网址:https://blog.csdn.net/qq_29648651/article/details/78503853;在这我是用.yml后缀的文件格式。右键application文件选择Refact,选择Rename,将后缀改为yml;
spring: datasource: name: test #数据库名 url: jdbc:mysql://localhost:3306/test #url username: root #用户名 password: 123456 #密码 driver-class-name: com.mysql.jdbc.Driver #数据库链接驱动
13.运行项目启动类TestApplication.java
可以发现上面有一个WARN警告,那是因为还没有配置编写MyBatis的相关文件,下面会进行详解;
2019-08-02 09:14:27.473 WARN 9120 --- [ main] o.m.s.mapper.ClassPathMapperScanner : No MyBatis mapper was found in '[com.example.test]' package. Please check your configuration.
14.在浏览器中输入localhost:8080,回车显示初始的index界面;到这项目的初步搭建已经完成,下面可以下一些简单的业务逻辑,比如从数据库获取信息,登录之类的简单功能;
15.在进行下一步编写时,我们先来链接一下数据库;点击右侧的Database,点“加号”,新建数据库链接;
16.填写数据库相关信息,点击Test Connection;
17.如果链接失败可能是驱动的问题,点击左上角的小扳手,进入数据库设置界面
18.连接成功后,显示数据库信息,user表的基本信息也显示了,下面就照这个来了;
19.SpringBoot项目大概分为四层:
(1)DAO层:包括XxxMapper.java(数据库访问接口类),XxxMapper.xml(数据库链接实现);(这个命名,有人喜欢用Dao命名,有人喜欢用Mapper,看个人习惯了吧)
(2)Bean层:也叫model层,模型层,entity层,实体层,就是数据库表的映射实体类,存放POJO对象;
(3)Service层:也叫服务层,业务层,包括XxxService.java(业务接口类),XxxServiceImpl.java(业务实现类);(可以在service文件夹下新建impl文件放业务实现类,也可以把业务实现类单独放一个文件夹下,更清晰)
(4)Web层:就是Controller层,实现与web前端的交互。
依照上面四层,创建目录结构如下:
20.代码展示:
(1)在application配置文件中添加MyBatis配置:
spring: datasource: name: test #数据库名 url: jdbc:mysql://localhost:3306/test #url username: root #用户名 password: 123456 #密码 driver-class-name: com.mysql.jdbc.Driver #数据库链接驱动 mybatis: mapper-locations: classpath:mapper/*.xml #配置映射文件 type-aliases-package: com.example.test.bean #配置实体类
(2)pom.xml文件配置信息(备注:这个文件以前没有,2019/12/9日粉丝发现的,这个里面也添加了单元测试所需的配置,记得要重新导一下Maven包哦)
<?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> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.1.6.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.example</groupId> <artifactId>test</artifactId> <version>0.0.1-SNAPSHOT</version> <name>test</name> <description>Demo project for Spring Boot</description> <properties> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-jdbc</artifactId> </dependency> <!--thymeleaf模板引擎配置--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-thymeleaf</artifactId> </dependency> <!--Web依赖--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <!--MyBatis配置--> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>2.1.0</version> </dependency> <!--MySQL数据库配置--> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.41</version> <scope>runtime</scope> </dependency> <!--单元测试配置--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
(3)Bean实体类,依据数据库表,生成set和get方法;
package com.example.test.bean; public class UserBean { private int id; private String name; private String password; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } }
(4)DAO层访问数据库接口文件:
package com.example.test.mapper; import com.example.test.bean.UserBean; public interface UserMapper { UserBean getInfo(String name,String password); }
(5)DAO层访问数据库实现文件(需在resource包下创建mapper文件夹,然后再创建一个UserMapper.xml.在application配置文件中mybatis:mapper-locations:对应的就是该文件地址),注意<mapper>标签的namespace属性要填写 访问数据库接口类文件路径:
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" > <mapper namespace="com.example.test.mapper.UserMapper"> <select id="getInfo" parameterType="String" resultType="com.example.test.bean.UserBean"> SELECT * FROM user WHERE name = #{name} AND password = #{password} </select> </mapper>
(6)Service层业务接口类编写:
package com.example.test.service; import com.example.test.bean.UserBean; public interface UserService { UserBean loginIn(String name,String password); }
(7)Service层业务实现类编写,注意要注解@Service,注入DAO:
package com.example.test.serviceImpl; import com.example.test.bean.UserBean; import com.example.test.mapper.UserMapper; import com.example.test.service.UserService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; @Service public class UserServiceImpl implements UserService { //将DAO注入Service层 @Autowired private UserMapper userMapper; @Override public UserBean loginIn(String name, String password) { return userMapper.getInfo(name,password); } }
(8)项目启动类要添加注解@MapperScan项目启动时扫描mapper接口,否则会报错找不到mapper文件:
package com.example.test; import org.mybatis.spring.annotation.MapperScan; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication @MapperScan("com.example.test.mapper") public class TestApplication { public static void main(String[] args) { SpringApplication.run(TestApplication.class, args); } }
(9)编写测试类,看是否能成功 访问数据库,获取数据库信息:
package com.example.test; import com.example.test.bean.UserBean; import com.example.test.service.UserService; 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 TestApplicationTests { @Autowired UserService userService; @Test public void contextLoads() { UserBean userBean = userService.loginIn("a","a"); System.out.println("该用户ID为:"); System.out.println(userBean.getId()); } }
(10) controller层,注意添加@controller注解,注入Service服务:
package com.example.test.controller; import com.example.test.bean.UserBean; import com.example.test.service.UserService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; @Controller public class LoginController { //将Service注入Web层 @Autowired UserService userService; @RequestMapping("/login") public String show(){ return "login"; } @RequestMapping(value = "/loginIn",method = RequestMethod.POST) public String login(String name,String password){ UserBean userBean = userService.loginIn(name,password); if(userBean!=null){ return "success"; }else { return "error"; } } }
(11)html文件:
login.html
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>login</title> </head> <body> <form role="form" action = "/loginIn" method="post"> 账号:<input type="text" id="name" name = "name"> <br> 密码:<input type="password" id = "password" name = "password"> <br> <input type="submit" id = "login" value = "login"> </form> </body> </html>
success.html
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>success</title> </head> <body> <h1>登录成功!</h1> </body> </html>
error.html
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>error</title> </head> <body> <h1>登录失败!</h1> </body> </html>
21.先运行测试类,看是否成功获取数据库信息:
22.同时发现一条警告信息,是数据库连接的jar包问题:
2019-08-02 11:25:04.150 WARN 16868 --- [ main] com.zaxxer.hikari.util.DriverDataSource : Registered driver with driverClassName=com.mysql.jdbc.Driver was not found, trying direct instantiation.
打开pom.xml文件,发现配置文件中未指定数据库连接的jar包的版本号,用version标签引入
<version>5.1.41</version>
重新运行测试类,WARN警告消除
23.运行TestApplication.java文件,启动项目,无任何WARN警告信息,进入浏览器输入localhost:8080/login
项目到这里就算完美结束了。
项目源码放在GitHub上,可以下载参考:https://github.com/redesperado/SpringBoot.git
有一个基于本项目添加增删改查功能的项目,仅供参考:https://github.com/redesperado/test1.git
附一个微服务项目搭建过程,有想学的可以参考一下
IDEA基于springboot采用Dubbo+zookeeper+Redis搭建微服务项目-详细教程:https://blog.csdn.net/baidu_39298625/article/details/108330298
大家如果在创建过程 中遇到什么问题,可以在下边提供的链接中看看,这些是我在创建项目过程遇到的问题,希望可以帮到大家:
1.启动报错:Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
https://blog.csdn.net/baidu_39298625/article/details/98261102
2.mapper.xml文件数据库字段报红
https://blog.csdn.net/baidu_39298625/article/details/98265845
3.项目正常启动,访问默认index页面时404
https://blog.csdn.net/baidu_39298625/article/details/98501840
4. 链接MySQL数据库报错:java.sql.SQLException: The server time zone value '�й���ʱ��' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc time zone value if you want to utilize time zone support.
https://blog.csdn.net/baidu_39298625/article/details/100915264
5.中文用户名登录失败,无报错信息
https://blog.csdn.net/baidu_39298625/article/details/103494461
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