SpringBoot高级

01-SpringBoot高级-今日内容

  • SpringBoot自定配置
    • SpringBoot事件监听
    • SpringBoot流程分析
    • SpringBoot监控
    • SpringBoot部署

02-SpringBoot自动配置-Condition-1

Condition是Spring4.0后引入的条件化配置接口,通过实现Condition接口可以完成有条件的加载相应的Bean

@Conditional要配和Condition的实现类(ClassCondition)进行使用

  • ClassCondition
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23

public class ClassCondition implements Condition {
/**
*
* @param context 上下文对象。用于获取环境,IOC容器,ClassLoader对象
* @param metadata 注解元对象。 可以用于获取注解定义的属性值
* @return
*/
@Override
public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {

//1.需求: 导入Jedis坐标后创建Bean
//思路:判断redis.clients.jedis.Jedis.class文件是否存在
boolean flag = true;
try {
Class<?> cls = Class.forName("redis.clients.jedis.Jedis");
} catch (ClassNotFoundException e) {
flag = false;
}
return flag;

}
}
  • UserConfig
1
2
3
4
5
6
7
8
9
10
@Configuration
public class UserConfig {

@Bean
@Conditional(ClassCondition.class)
public User user(){
return new User();
}

}

测试

1
2
3
4
5
6
7
8
9
10
11
12
13
@SpringBootApplication
public class SpringbootConditionApplication {

public static void main(String[] args) {
//启动SpringBoot的应用,返回Spring的IOC容器
ConfigurableApplicationContext context = SpringApplication.run(SpringbootConditionApplication.class, args);

Object user = context.getBean("user");
System.out.println(user);

}

}

03-SpringBoot自动配置-Condition-2

需求:将类的判断定义为动态的。判断哪个字节码文件存在可以动态指定。

自定义条件注解类

1
2
3
4
5
6
7
8
9
10
11
12
import org.springframework.context.annotation.Conditional;

import java.lang.annotation.*;


@Target({ElementType.TYPE, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Conditional(ClassCondition.class)
public @interface ConditionOnClass {
String[] value();
}

注意:此处@ConditionOnClass为自定义注解

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
@Configuration
public class UserConfig {

@Bean
//@Conditional(ClassCondition.class)
@ConditionOnClass("com.alibaba.fastjson.JSON")
public User user(){
return new User();
}

@Bean
@ConditionalOnProperty(name = "itcast",havingValue = "itheima")
public User user2(){
return new User();
}

}

测试User对象的创建

1
2
3
4
5
6
7
8
9
10
11
12
13
@SpringBootApplication
public class SpringbootConditionApplication {

public static void main(String[] args) {
//启动SpringBoot的应用,返回Spring的IOC容器
ConfigurableApplicationContext context = SpringApplication.run(SpringbootConditionApplication.class, args);

Object user = context.getBean("user");
System.out.println(user);

}

}

查看条件注解源码

1571383973124

SpringBoot 提供的常用条件注解:

ConditionalOnProperty:判断配置文件中是否有对应属性和值才初始化Bean

ConditionalOnClass:判断环境中是否有对应字节码文件才初始化Bean

ConditionalOnMissingBean:判断环境中没有对应Bean才初始化Bean

04-SpringBoot自动配置-切换内置web服务器

查看继承关系图

1571306414687

排除Tomcat

1571306366201

pom文件中的排除依赖效果

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<!--排除tomcat依赖-->
<exclusions>
<exclusion>
<artifactId>spring-boot-starter-tomcat</artifactId>
<groupId>org.springframework.boot</groupId>
</exclusion>
</exclusions>
</dependency>

<!--引入jetty的依赖-->
<dependency>
<artifactId>spring-boot-starter-jetty</artifactId>
<groupId>org.springframework.boot</groupId>
</dependency>

05-SpringBoot自动配置-Enable注解原理

  • SpringBoot不能直接获取在其他工程中定义的Bean

    演示代码:

    springboot-enable工程

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    /**
    * @ComponentScan 扫描范围:当前引导类所在包及其子包
    *
    * com.itheima.springbootenable
    * com.itheima.config
    * //1.使用@ComponentScan扫描com.itheima.config包
    * //2.可以使用@Import注解,加载类。这些类都会被Spring创建,并放入IOC容器
    * //3.可以对Import注解进行封装。
    */

    //@ComponentScan("com.itheima.config")
    //@Import(UserConfig.class)
    @EnableUser
    @SpringBootApplication
    public class SpringbootEnableApplication {

    public static void main(String[] args) {
    ConfigurableApplicationContext context = SpringApplication.run(SpringbootEnableApplication.class, args);

    //获取Bean
    Object user = context.getBean("user");
    System.out.println(user);

    }

    }

pom中引入springboot-enable-other

1
2
3
4
5
6

<dependency>
<groupId>com.itheima</groupId>
<artifactId>springboot-enable-other</artifactId>
<version>0.0.1-SNAPSHOT</version>
</dependency>

springboot-enable-other工程

UserConfig

1
2
3
4
5
6
7
8
9
10
@Configuration
public class UserConfig {

@Bean
public User user() {
return new User();
}


}

EnableUser注解类

1
2
3
4
5
6
7
8
9
10
11
import org.springframework.context.annotation.Import;

import java.lang.annotation.*;

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Import(UserConfig.class)
public @interface EnableUser {

}

原因@ComponentScan 扫描范围:当前引导类所在包及其子包

三种解决方案:

1.使用@ComponentScan扫描com.itheima.config

2.可以使用@Import注解,加载类。这些类都会被Spring创建,并放入IOC容器

3.可以对Import注解进行封装。

重点:Enable注解底层原理是使用@Import注解实现Bean的动态加载

06-SpringBoot自动配置-@Import详解

@Enable底层依赖于@Import注解导入一些类,使用@Import导入的类会被Spring加载到IOC容器中。而@Import提供4中用法:

①导入Bean

②导入配置类

③导入 ImportSelector 实现类。一般用于加载配置文件中的类

④导入 ImportBeanDefinitionRegistrar 实现类。

  • 导入Bean @Import(User.class)

  • 导入配置类 @Import(UserConfig.class)

  • 导入 ImportSelector 实现类 @Import(MyImportSelector.class)

    MyImportSelector

    1
    2
    3
    4
    5
    6
    public class MyImportSelector implements ImportSelector {
    @Override
    public String[] selectImports(AnnotationMetadata importingClassMetadata) {
    return new String[]{"com.itheima.domain.User", "com.itheima.domain.Role"};
    }
    }
  • 导入 ImportBeanDefinitionRegistrar 实现类。@Import({MyImportBeanDefinitionRegistrar.class})

    1
    2
    3
    4
    5
    6
    7
    8
    9
    public class MyImportBeanDefinitionRegistrar implements ImportBeanDefinitionRegistrar {
    @Override
    public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
    AbstractBeanDefinition beanDefinition = BeanDefinitionBuilder.rootBeanDefinition(User.class).getBeanDefinition();
    registry.registerBeanDefinition("user", beanDefinition);


    }
    }

SpringbootEnableApplication测试代码

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
 
/**
* Import4中用法:
* 1. 导入Bean
* 2. 导入配置类
* 3. 导入ImportSelector的实现类。
* 4. 导入ImportBeanDefinitionRegistrar实现类
*/

//@Import(User.class)
//@Import(UserConfig.class)
//@Import(MyImportSelector.class)
//@Import({MyImportBeanDefinitionRegistrar.class})

@SpringBootApplication
public class SpringbootEnableApplication {

public static void main(String[] args) {
ConfigurableApplicationContext context = SpringApplication.run(SpringbootEnableApplication.class, args);

/*//获取Bean
Object user = context.getBean("user");
System.out.println(user);*/

/*User user = context.getBean(User.class);
System.out.println(user);

Role role = context.getBean(Role.class);
System.out.println(role);*/

/* Object user = context.getBean("user");
System.out.println(user);*/
Map<String, User> map = context.getBeansOfType(User.class);
System.out.println(map);

}

}

@EnableAutoConfiguration中使用的是第三种方式:@Import(AutoConfigurationImportSelector.class)

07-SpringBoot自动配置-@EnableAutoConfiguration详解

1571387384701

  • @EnableAutoConfiguration注解内部使用 @Import(AutoConfigurationImportSelector.**class**)来加载配置类。

  • 配置文件位置:META-INF/spring.factories,该配置文件中定义了大量的配置类,当 SpringBoot 应用启动时,会自动加载这些配置类,初始化Bean

  • 并不是所有的Bean都会被初始化,在配置类中使用Condition来加载满足条件的Bean

08-SpringBoot自动配置-自定义starter步骤分析

需求:自定义redis-starter。要求当导入redis坐标时,SpringBoot自动创建Jedis的Bean。

步骤:

①创建 redis-spring-boot-autoconfigure 模块

②创建 redis-spring-boot-starter 模块,依赖 redis-spring-boot-autoconfigure的模块

③在 redis-spring-boot-autoconfigure 模块中初始化 Jedis 的 Bean。并定义META-INF/spring.factories 文件

④在测试模块中引入自定义的 redis-starter 依赖,测试获取 Jedis 的Bean,操作 redis。

09-SpringBoot自动配置-自定义starter实现-1

  1. 创建redis-spring-boot-starter工程

    pom文件中引入redis-spring-boot-autoconfigure
1
2
3
4
5
6
<!--引入configure-->
<dependency>
<groupId>com.itheima</groupId>
<artifactId>redis-spring-boot-autoconfigure</artifactId>
<version>0.0.1-SNAPSHOT</version>
</dependency>
  1. 创建redis-spring-boot-autoconfigure配置工程

创建RedisProperties配置文件参数绑定类

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
@ConfigurationProperties(prefix = "redis")
public class RedisProperties {

private String host = "localhost";
private int port = 6379;


public String getHost() {
return host;
}

public void setHost(String host) {
this.host = host;
}

public int getPort() {
return port;
}

public void setPort(int port) {
this.port = port;
}
}

创建RedisAutoConfiguration自动配置类

1
2
3
4
5
6
7
8
9
10
11
12
13
14
@Configuration
@EnableConfigurationProperties(RedisProperties.class)
public class RedisAutoConfiguration {


/**
* 提供Jedis的bean
*/
@Bean
public Jedis jedis(RedisProperties redisProperties) {

return new Jedis(redisProperties.getHost(), redisProperties.getPort());
}
}

在resource目录下创建META-INF文件夹并创建spring.factories

注意:”\ “是换行使用的

1
2
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
com.itheima.redis.config.RedisAutoConfiguration
  1. 在springboot-enable工程中引入自定义的redis的starter
1
2
3
4
5
6
<!--自定义的redis的starter-->
<dependency>
<groupId>com.itheima</groupId>
<artifactId>redis-spring-boot-starter</artifactId>
<version>0.0.1-SNAPSHOT</version>
</dependency>

在SpringbootEnableApplication启动类中测试

1
2
Jedis jedis = context.getBean(Jedis.class);
System.out.println(jedis);

10-SpringBoot自动配置-自定义starter实现-2

测试springboot-enable工程中的application.properties中的配置参数

1
redis.port=6666

使用注解完成有条件加载配置类

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
@Configuration
@EnableConfigurationProperties(RedisProperties.class)
@ConditionalOnClass(Jedis.class)
public class RedisAutoConfiguration {


/**
* 提供Jedis的bean
*/
@Bean
@ConditionalOnMissingBean(name = "jedis")
public Jedis jedis(RedisProperties redisProperties) {
System.out.println("RedisAutoConfiguration....");
return new Jedis(redisProperties.getHost(), redisProperties.getPort());
}
}

11-SpringBoot事件监听

Java中的事件监听机制定义了以下几个角色:

①事件:Event,继承 java.util.EventObject 类的对象

②事件源:Source ,任意对象Object

③监听器:Listener,实现 java.util.EventListener 接口 的对象

SpringBoot 在项目启动时,会对几个监听器进行回调,我们可以实现这些监听器接口,在项目启动时完成一些操作。

  • ApplicationContextInitializer、

  • SpringApplicationRunListener、

  • CommandLineRunner、

  • ApplicationRunner

自定义监听器的启动时机:MyApplicationRunner和MyCommandLineRunner都是当项目启动后执行,使用@Component放入容器即可使用

MyApplicationRunner

1
2
3
4
5
6
7
8
9
10
11
/**
* 当项目启动后执行run方法。
*/
@Component
public class MyApplicationRunner implements ApplicationRunner {
@Override
public void run(ApplicationArguments args) throws Exception {
System.out.println("ApplicationRunner...run");
System.out.println(Arrays.asList(args.getSourceArgs()));
}
}

MyCommandLineRunner

1
2
3
4
5
6
7
8
@Component
public class MyCommandLineRunner implements CommandLineRunner {
@Override
public void run(String... args) throws Exception {
System.out.println("CommandLineRunner...run");
System.out.println(Arrays.asList(args));
}
}

MyApplicationContextInitializer的使用要在resource文件夹下添加META-INF/spring.factories

1
org.springframework.context.ApplicationContextInitializer=com.itheima.springbootlistener.listener.MyApplicationContextInitializer
1
2
3
4
5
6
7
@Component
public class MyApplicationContextInitializer implements ApplicationContextInitializer {
@Override
public void initialize(ConfigurableApplicationContext applicationContext) {
System.out.println("ApplicationContextInitializer....initialize");
}
}

MySpringApplicationRunListener的使用要添加构造器

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
public class MySpringApplicationRunListener implements SpringApplicationRunListener {

public MySpringApplicationRunListener(SpringApplication application, String[] args) {
}

@Override
public void starting() {
System.out.println("starting...项目启动中");
}

@Override
public void environmentPrepared(ConfigurableEnvironment environment) {
System.out.println("environmentPrepared...环境对象开始准备");
}

@Override
public void contextPrepared(ConfigurableApplicationContext context) {
System.out.println("contextPrepared...上下文对象开始准备");
}

@Override
public void contextLoaded(ConfigurableApplicationContext context) {
System.out.println("contextLoaded...上下文对象开始加载");
}

@Override
public void started(ConfigurableApplicationContext context) {
System.out.println("started...上下文对象加载完成");
}

@Override
public void running(ConfigurableApplicationContext context) {
System.out.println("running...项目启动完成,开始运行");
}

@Override
public void failed(ConfigurableApplicationContext context, Throwable exception) {
System.out.println("failed...项目启动失败");
}
}

12-SpringBoot流程分析-初始化

  1. 配置启动引导类(判断是否有启动主类)

  2. 判断是否是Web环境

  3. 获取初始化类、监听器类

1571369439416

13-SpringBoot流程分析-run

  1. 启动计时器

  2. 执行监听器

  3. 准备环境

  4. 打印banner:可以resource下粘贴自定义的banner

  5. 创建context

    1
    refreshContext(context);

    执行refreshContext方法后才真正创建Bean

1571373793325

14-SpringBoot监控-actuator基本使用

①导入依赖坐标

1
2
3
4
5
6
7
<dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-actuator</artifactId>

</dependency>

②访问http://localhost:8080/acruator

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
{
"_links":{
"self":{
"href":"http://localhost:8080/actuator",
"templated":false
},
"health":{
"href":"http://localhost:8080/actuator/health",
"templated":false
},
"health-component-instance":{
"href":"http://localhost:8080/actuator/health/{component}/{instance}",
"templated":true
},
"health-component":{
"href":"http://localhost:8080/actuator/health/{component}",
"templated":true
},
"info":{
"href":"http://localhost:8080/actuator/info",
"templated":false
}
}
}

http://localhost:8080/actuator/info

在application.properties中配置

1
2
info.name=lucy
info.age=99

http://localhost:8080/actuator/health

开启健康检查详细信息

1
management.endpoint.health.show-details=always
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
{
"status":"UP",
"details":{
"diskSpace":{
"status":"UP",
"details":{
"total":159579508736,
"free":13558104064,
"threshold":10485760
}
},
"redis":{
"status":"UP",
"details":{
"version":"2.4.5"
}
}
}
}

15-SpringBoot监控-actuator开启所有endpoint

开启所有endpoint

在application.properties中配置:

1
management.endpoints.web.exposure.include=*

开启所有endpoint的返回结果:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
{
"_links":{
"self":{
"href":"http://localhost:8080/actuator",
"templated":false
},
"auditevents":{
"href":"http://localhost:8080/actuator/auditevents",
"templated":false
},
"beans":{
"href":"http://localhost:8080/actuator/beans",
"templated":false
},
"caches-cache":{
"href":"http://localhost:8080/actuator/caches/{cache}",
"templated":true
},
"caches":{
"href":"http://localhost:8080/actuator/caches",
"templated":false
},
"health-component-instance":{
"href":"http://localhost:8080/actuator/health/{component}/{instance}",
"templated":true
},
"health":{
"href":"http://localhost:8080/actuator/health",
"templated":false
},
"health-component":{
"href":"http://localhost:8080/actuator/health/{component}",
"templated":true
},
"conditions":{
"href":"http://localhost:8080/actuator/conditions",
"templated":false
},
"configprops":{
"href":"http://localhost:8080/actuator/configprops",
"templated":false
},
"env":{
"href":"http://localhost:8080/actuator/env",
"templated":false
},
"env-toMatch":{
"href":"http://localhost:8080/actuator/env/{toMatch}",
"templated":true
},
"info":{
"href":"http://localhost:8080/actuator/info",
"templated":false
},
"loggers":{
"href":"http://localhost:8080/actuator/loggers",
"templated":false
},
"loggers-name":{
"href":"http://localhost:8080/actuator/loggers/{name}",
"templated":true
},
"heapdump":{
"href":"http://localhost:8080/actuator/heapdump",
"templated":false
},
"threaddump":{
"href":"http://localhost:8080/actuator/threaddump",
"templated":false
},
"metrics-requiredMetricName":{
"href":"http://localhost:8080/actuator/metrics/{requiredMetricName}",
"templated":true
},
"metrics":{
"href":"http://localhost:8080/actuator/metrics",
"templated":false
},
"scheduledtasks":{
"href":"http://localhost:8080/actuator/scheduledtasks",
"templated":false
},
"httptrace":{
"href":"http://localhost:8080/actuator/httptrace",
"templated":false
},
"mappings":{
"href":"http://localhost:8080/actuator/mappings",
"templated":false
}
}
}

16-SpringBoot监控-springboot admin图形化界面使用

SpringBoot Admin 有两个角色,客户端(Client)和服务端(Server)。

以下为创建服务端和客户端工程步骤:

admin-server:

①创建 admin-server 模块

②导入依赖坐标 admin-starter-server

1571812312998

1
2
3
4
<dependency>
<groupId>de.codecentric</groupId>
<artifactId>spring-boot-admin-starter-server</artifactId>
</dependency>

③在引导类上启用监控功能@EnableAdminServer

1
2
3
4
5
6
7
8
9
@EnableAdminServer
@SpringBootApplication
public class SpringbootAdminServerApplication {

public static void main(String[] args) {
SpringApplication.run(SpringbootAdminServerApplication.class, args);
}

}

admin-client:

①创建 admin-client 模块

②导入依赖坐标 admin-starter-client

1
2
3
4
<dependency>
<groupId>de.codecentric</groupId>
<artifactId>spring-boot-admin-starter-client</artifactId>
</dependency>

③配置相关信息:server地址等

1
2
3
4
5
# 执行admin.server地址
spring.boot.admin.client.url=http://localhost:9000

management.endpoint.health.show-details=always
management.endpoints.web.exposure.include=*

④启动server和client服务,访问server

17-SpringBoot部署

SpringBoot 项目开发完毕后,支持两种方式部署到服务器:

①jar包(官方推荐)

②war包

更改pom文件中的打包方式为war

修改启动类

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;

@SpringBootApplication
public class SpringbootDeployApplication extends SpringBootServletInitializer {

public static void main(String[] args) {
SpringApplication.run(SpringbootDeployApplication.class, args);
}


@Override
protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
return builder.sources(SpringbootDeployApplication.class);
}
}

指定打包的名称

1
2
3
4
5
6
7
8
9
<build>
<finalName>springboot</finalName>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>