Spring Boot创建一个简单的框架

在IDEA里创建一个Spring Boot 框架

因为是初步学习，pom.xml里的依赖不在这里选择，而是在创建完成后，自己添加。

这是创建一个初始Spring boot项目的结构。其它结构要后续添加。

在为pom.xml添加依赖之前先创建generatorConfig.xml文件，该文件创建在resources/generator文件夹里。
代码为

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration
        PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
<generatorConfiguration>
    <!--数据库驱动-->
    <!--添加mysql驱动的位置-->
    <classPathEntry  location="C:\Program Files\Apache Software Foundation\maven-repository\mysql\mysql-connector-java\8.0.11\mysql-connector-java-8.0.11.jar"/>
    <context id="mysql" targetRuntime="MyBatis3">
        <commentGenerator>
            <property name="suppressDate" value="true"/>
            <!-- 是否去除自动生成的注释 true：是 ： false:否 -->
            <property name="suppressAllComments" value="true"/>
        </commentGenerator>
        <!--数据库链接URL，用户名、密码 -->
        <jdbcConnection driverClass="com.mysql.cj.jdbc.Driver" connectionURL="jdbc:mysql://localhost:3306/test?serverTimezone=GMT%2B8 &characterEncoding=utf-8&useSSL=false&" userId="root" password= "123456" >
        </jdbcConnection>
        <javaTypeResolver>
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>
        <!-- 生成模型的包名和位置-->
        <javaModelGenerator targetPackage="com.project.gc.domain" targetProject="src/main/java">
            <property name="enableSubPackages" value="true"/>
            <property name="trimStrings" value="true"/>
        </javaModelGenerator>
        <!-- 生成映射文件的包名和位置-->
        <sqlMapGenerator targetPackage="com.project.gc.dao" targetProject="src/main/resources">
            <property name="enableSubPackages" value="true"/>
        </sqlMapGenerator>
        <!-- 生成DAO的包名和位置-->
        <javaClientGenerator type="XMLMAPPER" targetPackage="com.project.gc.dao" targetProject="src/main/java">
            <property name="enableSubPackages" value="true"/>
        </javaClientGenerator>
        <!-- 要生成的表 tableName是数据库中的表名或视图名 domainObjectName是实体类名-->
        <table tableName="t_users"
               domainObjectName="Users">
            <generatedKey column="id" sqlStatement="MySql" identity="true" />
        </table>
        <table tableName="t_news"
               domainObjectName="News">
            <generatedKey column="id" sqlStatement="MySql" identity="true" />
        </table>
        <table tableName="t_recruit"
               domainObjectName="Recruit">
            <generatedKey column="id" sqlStatement="MySql" identity="true" />
        </table>
    </context>
</generatorConfiguration>

接着在pom.xml里添加依赖代码如下

<?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.project</groupId>
    <artifactId>gc</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>gc</name>
    <description>gc project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.0.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>
        <!--spring依赖全家桶-->
        <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>

        <!--web依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!--mybatis依赖-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.2</version>
        </dependency>

        <!--jdbc依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>

        <!--spring boot 全家桶 end-->

        <!--druid数据库连接池-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.9</version>
        </dependency>

        <!--mysql驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

        <!--log4j-->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>


    </dependencies>

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

            <plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.6</version>
                <configuration>
                    <!--generatorConfigurationFile的位置-->
                    <configurationFile>${basedir}/src/main/resources/generator/generatorConfig.xml</configurationFile>
                    <overwrite>true</overwrite>
                    <verbose>true</verbose>
                </configuration>
            </plugin>
        </plugins>
    </build>


</project>

然后在IDEA里运行mybatis generator插件

插件运行完后的结构为

接下来在项目里创建controller、service文件夹

然后在service文件夹里创建UserService
代码如下

package com.project.gc.service;

import com.project.gc.dao.UsersMapper;
import com.project.gc.domain.Users;
import com.project.gc.domain.UsersExample;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;

@Service
public class UsersService {
    @Resource
    private UsersMapper usersMapper;

    public Users findById(int id){
        return usersMapper.selectByPrimaryKey(id);
    }
    public Users findByUserName(String userNmae){
        UsersExample example = new UsersExample();
        example.or().andUsernameEqualTo(userNmae);
        return usersMapper.selectByExample(example);
    }

    public int addUser(Users users){
        return usersMapper.insertSelective(users);
    }
}

遇到这个错误的话，将dao/UsersMapper里selectByExample方法的返回值类型改成Users

接下来在controller文件夹里创建UsersController
代码如下

package com.project.gc.controller;

import com.project.gc.domain.Users;
import com.project.gc.service.UsersService;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;

@RestController
public class UsersController {
    @Resource
    private UsersService usersService;

    @RequestMapping(value = "get",method = RequestMethod.GET)
    public Users getUserById(@RequestParam(value = "id",required = true) int id){
        return usersService.findById(id);
    }

    @RequestMapping(value = "username",method = RequestMethod.GET)
    public Users getUserByUserName(@RequestParam(value = "userName",required = true) String userName){
        return usersService.findByUserName(userName);
    }

    public Users addUser(Users users){
        usersService.addUser(users);
        return users;
    }
}

接下配置application.properties文件

server.port=8080

#spring设置
spring.datasource.druid.url=jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC&verifyServerCertificate=false&useSSL=false&allowPublicKeyRetrieval=true
#连接驱动
spring.datasource.druid.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.druid.username=root
spring.datasource.druid.password=123456
spring.datasource.druid.initial-size=10
spring.datasource.druid.max-active=50
spring.datasource.druid.min-idle=10
spring.datasource.druid.max-wait=60000
spring.datasource.druid.pool-prepared-statements=true
spring.datasource.druid.max-pool-prepared-statement-per-connection-size=20
spring.datasource.druid.validation-query=SELECT 1 FROM DUAL
spring.datasource.druid.test-on-borrow=false
spring.datasource.druid.test-on-return=false
spring.datasource.druid.test-while-idle=true
spring.datasource.druid.time-between-eviction-runs-millis=60000
spring.datasource.druid.filters=stat,wall,log4j

然后运行入口程序GcApplication,发现报错
找不到Mapper文件

然后在入口程序GcApplication里添加扫描注解**@MapperScan(“com.project.gc.dao”)**

需要注意的是这个com.project.gc.dao是resources里的那个

然后重新运行，即可。
在浏览器地址栏输入http://127.0.0.1:8080/get?id=1,会接到json返回值