springboot学习(三):使用c3p0连接池集成mybatis及mybatis自动代码生成插件

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说明

springboot集成mybatis和使用c3p0连接池，当初学习时过程还是比较艰难的，以翟永超的博客为基础，再找各种资料博客进行学习，还有在学习mybatis自动代码生成插件时，遇到的问题也不少，今天在这里进行回顾总结下。

正文

构建springboot项目，添加依赖mybatis和mysql-connector-java，start.spring.io在构建也不支持c3p0的自动添加，需要到maven资源库找c3p0的依赖。这里同样放到本地的tomcat中运行，添加web依赖。使用自动插件，要在pom.xml中添加插件

<dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.2</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>

        <!--c3p0-->
        <dependency>
            <groupId>com.mchange</groupId>
            <artifactId>c3p0</artifactId>
            <version>0.9.5.2</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
    <!--mybatis generator 自动生成代码-->
    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
        </resources>

        <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>1.3.2</version>
                <configuration>
                    <configurationFile>${basedir}/src/main/resources/generator/generatorConfig.xml</configurationFile>
                    <overwrite>true</overwrite>
                    <verbose>true</verbose>
                </configuration>
            </plugin>
        </plugins>
    </build>

创建好项目后，需要对c3p0和mybatis进行配置，首先在application.properties文件中配置mysql

c3p0.datasource.driverClass=com.mysql.jdbc.Driver
c3p0.datasource.jdbcUrl=jdbc:mysql://localhost:3306/springboot
c3p0.datasource.user=root
c3p0.datasource.password=123
c3p0.datasource.minPoolSize=3
c3p0.datasource.maxPoolSize=100
c3p0.datasource.initialPoolSize=3

DataSourceConfig

@Configuration
public class DataSourceConfig {

    @ConfigurationProperties(prefix = "c3p0.datasource")
    @Primary
    @Bean(name = "dataSource")
    public DataSource dataSource(){
        return DataSourceBuilder.create().type(com.mchange.v2.c3p0.ComboPooledDataSource.class).build();
    }
}

MybatisConfig

@Configuration
public class MybatisConfig {

    @Autowired
    private DataSource dataSource;

    @Bean(name = "sqlSessionFactory")
    public SqlSessionFactoryBean sqlSessionFactory(ApplicationContext applicationContext) throws IOException {
        SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
        sessionFactory.setDataSource(dataSource);
        sessionFactory.setTypeAliasesPackage("com.example.mybatis.bean");
        Resource[] resources = new PathMatchingResourcePatternResolver()
                .getResources("classpath*:com/example/mybatis/mapper/*Mapper.xml");
        sessionFactory.setMapperLocations(resources);

        return sessionFactory;
    }
}

配置好c3p0和mybatis后，需要对插件进行配置，创建generatorConfig.xml
更详细的配置请见：http://www.mybatis.org/generator/configreference/xmlconfig.html

<?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>
    <classPathEntry location="./src/main/resources/lib/mysql-connector-java-5.1.25-bin.jar"></classPathEntry>
    <context id="DB2Tables" targetRuntime="Mybatis3">
        <commentGenerator>
            <!--是否不生成注释 默认为false 当不指定时也会生成注释，true不生成  true时所有代码合并将不能使用-->
            <property name="suppressAllComments" value="true"/>
        </commentGenerator>
        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://localhost:3306/springboot"
                        userId="root"
                        password="123"
        />
        <javaTypeResolver>
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>
        <!--实体类生成的包名和位置-->
        <javaModelGenerator targetPackage="com.example.mybatis.bean" targetProject="src/main/java">
            <property name="enableSubPackages" value="true" />
            <property name="trimStrings" value="true" />
        </javaModelGenerator>

        <!--映射文件生成的包名和位置-->
        <sqlMapGenerator targetPackage="com.example.mybatis.mapper"  targetProject="src/main/java">
            <property name="enableSubPackages" value="true" />
        </sqlMapGenerator>

        <!--DAO生成的包名和位置-->
        <javaClientGenerator type="XMLMAPPER" targetPackage="com.example.mybatis.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_teacher" domainObjectName="Teacher" enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="false" selectByExampleQueryId="false"></table>
        <!--<table tableName="user" domainObjectName="User" enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="false" selectByExampleQueryId="false"></table>-->
    </context>
</generatorConfiguration>

配置好后需要在maven的插件中执行，也可以创建maven执行快捷方式

源码地址：https://github.com/Edenwds/springboot_study/tree/master/mybatis