自定义启动器

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目录

🍁开发步骤

1.创建启动器项目

• 添加启动器相关依赖
• 创建属性配置类
• 创建自动配置类
• 编写自动配置文件(spring.factories)
• 使用自定义的启动器

🍁测试

• 创建个SpringBoot项目，导入依赖

<parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.2.2.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></properties><dependencies><!--引入spring‐boot‐starter；所有starter的基本配置--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter</artifactId></dependency><!--自动配置连接池--><dependency><groupId>com.alibaba</groupId><artifactId>druid</artifactId><version>1.1.12</version></dependency><dependency><groupId>c3p0</groupId><artifactId>c3p0</artifactId><version>0.9.1.2</version></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-configuration-processor</artifactId><optional>true</optional></dependency></dependencies>

• 创建属性配置类

@Component
@ConfigurationProperties(prefix ="spring.jdbc.datasource")
public class DataSourceProperties {
    private String driverClassName ;
    private String url;
    private String username;
    private String password;

    public String getDriverClassName(){return driverClassName;}

    public voidsetDriverClassName(String driverClassName){
        this.driverClassName = driverClassName;}

    public String getUrl(){return url;}

    public voidsetUrl(String url){
        this.url = url;}

    public String getUsername(){return username;}

    public voidsetUsername(String username){
        this.username = username;}

    public String getPassword(){return password;}

    public voidsetPassword(String password){
        this.password = password;}

    @Override
    public String toString(){return"DataSourceProperties{"+"driverClassName='"+ driverClassName +'\''+", url='"+ url +'\''+", username='"+ username +'\''+", password='"+ password +'\''+'}';}}

• 创建自动配置类

@SpringBootConfiguration  //当前类是个配置类
@EnableConfigurationProperties(DataSourceProperties.class)
public class DataSourceAutoConfiguration {
    @Autowired
    private DataSourceProperties dataSourceProperties;

   @Bean
    public DataSource createDataSource(){
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(dataSourceProperties.getDriverClassName());
        dataSource.setUrl(dataSourceProperties.getUrl());
        dataSource.setUsername(dataSourceProperties.getUsername());
        dataSource.setPassword(dataSourceProperties.getPassword());return dataSource;}}

• 编写自动配置属性文件
• 在 resource 文件夹下面新建 META-INF/spring.factories

org.springframework.boot.autoconfigure.EnableAutoConfiguration=com.study.config.DataSourceAutoConfiguration

• 执行install , 安装项目

🍁自定义启动器

• 重新创建个项目，引用SpringBoot_datasource的依赖

<!--依赖自定义启动器--><dependency><groupId>com.study</groupId><artifactId>SpringBoot_datasource</artifactId><version>1.0-SNAPSHOT</version></dependency>

• 配置连接池信息

server.port=8081
spring.jdbc.datasource.driverClassName=com.mysql.jdbc.Driver
spring.jdbc.datasource.url=jdbc:mysql:///springboot_datasource
spring.jdbc.datasource.username=root
spring.jdbc.datasource.password=root
spring.profiles.active=datasource

• 编写Controller类

@RestController
public class HelloAutoController {
    @Autowired
    private DataSource dataSource;

    @RequestMapping("/dataSource")
    public String dataSource(){
        System.out.println(dataSource.getClass());//打印DruidDataSource数据源return"Hello dataSource! ! ! ";}}

• 使用自定义启动类进行测试

🍁启动器支持多Druid和C3P0

• 添加创建druid和c3p0方法

@SpringBootConfiguration  //当前类是个配置类
@EnableConfigurationProperties(DataSourceProperties.class)
public class DataSourceAutoConfiguration {
    @Autowired
    private DataSourceProperties dataSourceProperties;
    @Bean
    @ConditionalOnProperty(value ="spring.jdbc.datasource.type",havingValue ="druid")
    public DataSource createDataSource(){
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(dataSourceProperties.getDriverClassName());
        dataSource.setUrl(dataSourceProperties.getUrl());
        dataSource.setUsername(dataSourceProperties.getUsername());
        dataSource.setPassword(dataSourceProperties.getPassword());return dataSource;}

    @Bean
    @ConditionalOnProperty(value ="spring.jdbc.datasource.type",havingValue ="c3p0")
    public DataSource createC3P0DataSource() throws Exception {
        ComboPooledDataSource dataSource = new ComboPooledDataSource();
        dataSource.setDriverClass(dataSourceProperties.getDriverClassName());
        dataSource.setJdbcUrl(dataSourceProperties.getUrl());
        dataSource.setUser(dataSourceProperties.getUsername());
        dataSource.setPassword(dataSourceProperties.getPassword());return dataSource;}}

• 配置文件中配置了spring.jdbc.datasource.type=druid使用druid数据源

server.port=8081
spring.jdbc.datasource.driverClassName=com.mysql.jdbc.Driver
spring.jdbc.datasource.url=jdbc:mysql:///springboot_datasource
spring.jdbc.datasource.username=root
spring.jdbc.datasource.password=root
spring.jdbc.datasource.type=druid

• 重新安装，再次测试

• 配置了spring.jdbc.datasource.type=c3p0使用c3p0数据源

server.port=8081
spring.jdbc.datasource.driverClassName=com.mysql.jdbc.Driver
spring.jdbc.datasource.url=jdbc:mysql:///springboot_datasource
spring.jdbc.datasource.username=root
spring.jdbc.datasource.password=root
spring.jdbc.datasource.type=c3p0

• 重新安装，再次测试