ConfigurationProperties 接口
public @interface ConfigurationProperties {
@AliasFor("prefix")
String value() default "";
@AliasFor("value")
String prefix() default "";
}
在类名上加上 @ConfigurationProperties 注解，读取 application.properties 配置 Bean
@ConfigurationProperties("spring.datasource")
@Component
@Data
public class DataSourceBean {
private String url;
private String username;
private String password;
}
spring.datasource.url=jdbc:mysql://localhost:3306/kangpan?useSSL=false&useUnicode=true&characterEncoding=utf8&serverTimezone=UTC&useAffectedRows=true
spring.datasource.username=root
spring.datasource.password=
启动项目 控制台打印 url
@Component
@Slf4j
public class TestRunner implements ApplicationRunner {
@Autowired
private DataSourceBean dataSourceBean;
@Override
public void run(ApplicationArguments args) throws Exception {
log.info(dataSourceBean.getUrl());
}
配置 Bean 的属性
@RestController
@RequestMapping("/test")
@ConfigurationProperties(prefix = "spring.datasource")
@Slf4j
public class Test {
private String username;
public void setUsername(String username) {
this.username = username;
}
@GetMapping(path = "/")
public String test() {
return username;
}
}
浏览器输入 http://localhost:8081/test/ 打印了 root
@Component 配置 Bean （@Repository @Service @Controller 等效），定义一个接口 Todo
public interface Todo {
void print();
}
两个实现类 Foo Bar
@Slf4j
@Component
public class Foo implements Todo {
@Override
public void print() {
log.info("foo");
}
}
@Slf4j
@Component
public class Bar implements Todo {
@Override
public void print() {
log.info("bar");
}
}
@Autowired 根据类型注入，所有类型为 Todo 的全部注入 list ( 指 For 和 Bar)
@Inject 也是按类型注入，不过没有 required 属性
@Qualifier 根据名称注入
@Component("todos")
@Data
public class Todos {
@Autowired(required = false)
private List<Todo> list;
}
@RestController
@RequestMapping("/test")
@Slf4j
public class Test {
@Qualifier("todos")
@Autowired
private Todos todos;
@GetMapping(path = "/")
public String test() {
todos.getList().stream().forEach( e -> e.print());
return "";
}
}
浏览器输入 http://localhost:8081/test/ 控制台打印 bar 和 foo
如果 foo 要优先打印，在 Foo 类上加 @Order(value = 1)，值越小优先级越高，Foo 优先加载
实现延迟加载 定义一个 LazyDo
@Lazy
@Service
@Slf4j
public class LazyDo {
public void todo() {
log.info("lazy todo");
}
}
构造注入 lazyDao， @Resource 默认按名称注入，匹配不上按类型
@RestController
@RequestMapping("/test")
@Slf4j
public class Test {
private LazyDo lazyDo;
@Lazy
@Resource(name = "lazyDo")
private void setLazyDo(LazyDo lazyDo) {
this.lazyDo = lazyDo;
}
@GetMapping(path = "/")
public String test() {
lazyDo.todo();
return "";
}
}
启动项目 lazyDao 加载为 null
this.lazyDo = lazyDo; lazyDao: null lazyDo: "com.kangpan.model.lazy@7a65a360"
浏览器访问地址 http://localhost:8081/test/ 控制台打印 lazy todo
Bean 默认是单例，在类上加注解 @Scope("prototype") 多例
看下 Bean 初始化 及 销毁前 执行
@Service
@Slf4j
public class Todo {
@PostConstruct
public void init() {
log.info("init");
}
@PreDestroy
public void destroy() {
log.info("destroy");
}
}
运行项目 打印台输出 init ，关闭项目 打印台输出 destroy
根据当前环境配置 Bean
@Data
public class TestDev {
private String name;
public TestDev(String name) {
this.name = name;
}
}
application.properties 配置
test.name=testName // @Value 赋值
spring.profiles.active=dev // 当前环境
配置 dev 和 test 环境下的 Bean
@Configuration
public class Dev {
@Bean
@Profile("dev")
public TestDev testDev(@Value("${test.name}") String name) {
return new TestDev(name);
}
@Bean
@Profile("test")
public TestDev testTest(@Value("${test.name}") String name) {
return new TestDev(name);
}
}
@RestController
@RequestMapping("/test")
public class Test {
@Autowired
private TestDev testDev;
@GetMapping(path = "/")
public String test() {
return testDev.getName();
}
}
浏览器输入 http://localhost:8081/test/ 打印 testName
XML 配置 Bean 简化
属性
<property name = "name",value = "value" />
构造参数
<constructor-arg type="java.lang.String" value="value" />
<constructor-arg ref="refBean" />
集合
<property name = "name">
<map>
<entry key="key" value="value">
</map>
</property>
<property name = "name">
<map>
<entry key-ref="keyBean" value-ref="valueBean">
</map>
</property>
引用
<property name="name" ref="refBean" />
或者 XML 声明 p 命名空间，然后配置 Bean ，特殊字符 用 <![CDATA[]]> 转义
项目启动 @SpringBootApplication 注解中的 @EnableAutoConfiguration 会加载配置文件的 Bean
@SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class);
}
}
@EnableAutoConfiguration
public @interface SpringBootApplication {
}
在 resources/META-INF/spring.factories 文件中配置
org.springframework.boot.autoconfigure.EnableAutoConfiguration=com.kangpan.model.Configs
Configs 类
@EnableConfigurationProperties
@Import({ConfigFoo.class,ConfigBar.class})
public class Configs {
}
引入的 ConfigFoo ConfigBar 类
@Slf4j
public class ConfigBar {
public ConfigBar() {
log.info("ConfigBar");
}
}
@Slf4j
public class ConfigFoo {
public ConfigFoo() {
log.info("ConfigFoo");
}
}
启动项目 控制台打印 ConfigBar ConfigFoo，如果 @EnableConfigurationProperties 改成 @Configuration 不需要在 resources/META-INF/spring.factories 文件中配置
看下 Configuration 接口，加了 @Component 注解 会实例化 Bean
@Component
public @interface Configuration {}
@ConfigurationProperties 结合 @EnableConfigurationProperties 配置Bean
@ConfigurationProperties("spring.datasource") // 读取 application.properties 中的配置
@Data
public class DataSourceBean2 {
private String url;
private String username;
private String password;
}
application.properties 文件中配置
spring.datasource.url=jdbc:mysql://localhost:3306/kangpan?useSSL=false&useUnicode=true&characterEncoding=utf8&serverTimezone=UTC&useAffectedRows=true
spring.datasource.username=root
spring.datasource.password=
@EnableConfigurationProperties 使 @ConfigurationProperties 注解的类注入自身
@EnableConfigurationProperties(DataSourceBean2.class)
@Slf4j
public class DataSourceBeanConfig {
private DataSourceBean2 dataSourceBean2;
@Autowired
public DataSourceBeanConfig(DataSourceBean2 dataSourceBean2) {
this.dataSourceBean2 = dataSourceBean2;
log.info("url: {}",dataSourceBean2.getUrl());
}
}
spring.factories 配置 或者 DataSourceBeanConfig 类 加上 @Configuration 或者 @Component 注解
org.springframework.boot.autoconfigure.EnableAutoConfiguration=com.kangpan.model.DataSourceBeanConfig
控制台打印 url
自定义 XML 配置 Bean， 在 resource/bean.xml 配置 dataSourceBean
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
">
<bean id="dataSourceBean" class="com.kangpan.model.DataSourceBean"> </bean>
</beans>
结合 @ConfigurationProperties 属性赋值
@ConfigurationProperties("spring.datasource")
@Data
public class DataSourceBean {
private String url;
private String username;
private String password;
}
利用 @ImportResource 导入 bean.xml 配置的 Bean
@Component
@Slf4j
@ImportResource("classpath:bean.xml")
public class TestRunner implements ApplicationRunner {
@Autowired
private DataSourceBean dataSourceBean;
@Override
public void run(ApplicationArguments args) throws Exception {
log.info("dataSourceBean.getUrl():{}",dataSourceBean.getUrl());
}
项目启动 控制台打印 url
自定义 properties 配置 Bean，在 resources/dataSource.properties 配置
spring.datasource.url=jdbc:mysql://localhost:3306/kangpan?useSSL=false&useUnicode=true&characterEncoding=utf8&serverTimezone=UTC&useAffectedRows=true
spring.datasource.username=root
spring.datasource.password=
@PropertySource 加载指定文件的属性， @Value 赋值
@PropertySource("classpath:dataSource.properties")
@Data
@Component
public class DataSourcesBean {
@Value("${spring.datasource.url}")
private String url;
@Value("${spring.datasource.username}")
private String username;
@Value("${spring.datasource.password}")
private String password;
}
使用 @ConfigurationProperties 属性赋值
@PropertySource("classpath:dataSource.properties")
@Data
@Component
@ConfigurationProperties(prefix = "spring.datasource")
public class DataSourcesBean {
private String url;
private String username;
private String password;
}
@Component
@Slf4j
public class TestRunner implements ApplicationRunner {
@Autowired
private DataSourcesBean dataSourcesBean;
@Override
public void run(ApplicationArguments args) throws Exception {
log.info("dataSourcesBean.getUrl():{}",dataSourcesBean.getUrl());
}
运行项目 打印 url
