SpringBoot的常用特性

常用功能特性

SpringBoot应用启动入口

package com.imooc.springboot.study;

import org.springframework.boot.Banner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.WebApplicationType;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;

/**
 * @author sunchangheng
 */
@SpringBootApplication
public class SpringBootStudyApplication {
    public static void main(String[] args) {
        // 1. 第一种: 通过静态run方法
//            SpringApplication.run(SpringBootStudyApplication.class, args);
        
        // 2. 通过API调整应用行为
//        SpringApplication app = new SpringApplication(SpringBootStudyApplication.class);
//        app.setBannerMode(Banner.Mode.OFF);
//        app.setWebApplicationType(WebApplicationType.NONE);
//
//        app.run(args);
        
        // 3. SpringApplicationBuilder Fluent API 链式调用
        new SpringApplicationBuilder(SpringBootStudyApplication.class).bannerMode(Banner.Mode.OFF)
                .web(WebApplicationType.SERVLET).run(args);
        
    }
}

自动配置原理

配置文件

配置注入的方式

# 配置文件application.yml
 
# 自定义配置
imooc:
  springboot:
    version: 2.1, 2.1.4
    name: study

方式一

package com.imooc.springboot.study.controller;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @author sunchangheng
 */
@Slf4j
@RestController
@RequestMapping("/springboot")
public class TestController {

    @Value("${imooc.springboot.version}")
    private String version;
    
    @Value("${imooc.springboot.name}")
    private String name;
    
    @GetMapping("firstConfInject")
    public String firstConfInject() {
        log.info("version: {}, name: {}", version, name);
        return "ok";
    }
}

方式二

先写一个配置类

package com.imooc.springboot.study.config;

import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

/**
 * SpringBoot 配置文件中前缀是imooc.springboot的配置
 *
 * @author sunchangheng
 */
@Data
@Component
@ConfigurationProperties(prefix = "imooc.springboot")
public class SpringBootConfig {
    
    /**
     * 版本
     */
    private String version;
    
    /**
     * 名字
     */
    private String name;
}

在controller注入使用

@Resource
private final SpringBootConfig springBootConfig;

@GetMapping("/secondConfigInject")
public String secondConfigInject() {
    log.info("second: version: {} name: {}", springBootConfig.getVersion(), springBootConfig.getName());
    return "second ok";
}

定时任务

现在启动类上开启定时任务

配置定时任务类

package com.imooc.springboot.study.schedule;

import lombok.extern.slf4j.Slf4j;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

/**
 * SpringBoot 定时任务
 *
 * @author sunchangheng
 */
@Slf4j
@Component
public class BootSchedule {
    
    private final DateTimeFormatter fmt = DateTimeFormatter.ofPattern("HH;mm;ss");
    
    /**
     * 上一次开始执行时间点之后3000毫秒之后再执行
     */
    @Scheduled(fixedRate = 3000)
    public void schedule01() {
        log.info("schedule01 -> {}", LocalDateTime.now().format(fmt));
    }
    
    /**
     * 上一次执行完毕时间点之后3000毫秒之后再执行
     */
    @Scheduled(fixedDelay = 3000)
    public void schedule02() {
        log.info("schedule02 -> {}", LocalDateTime.now().format(fmt));
    }
    
    /**
     * 第一次延迟2s之后执行, 之后按照上一次开始执行时间点之后3s之后再执行
     */
    @Scheduled(initialDelay = 2000, fixedRate = 3000)
    public void schedule03() {
        log.info("schedule03 -> {}", LocalDateTime.now().format(fmt));
    }
    
    /**
     * 每3s执行一次
     */
    @Scheduled(cron = "*/3 * * * * ?")
    public void schedule04() {
        log.info("schedule04 -> {}", LocalDateTime.now().format(fmt));
    }
    
}

异步任务

先在启动类启用

编写异步处理类

package com.imooc.springboot.study.async;

import lombok.extern.slf4j.Slf4j;
import org.springframework.scheduling.annotation.Async;
import org.springframework.scheduling.annotation.AsyncResult;
import org.springframework.stereotype.Service;

import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;

/**
 * 异步处理服务
 *
 * @author sunchangheng
 */
@Slf4j
@Service
public class AsyncService {
    
    @Async("getAsyncExecutor")
    public void asyncProcess() {
        log.info("async process task, current thread name -> {}", Thread.currentThread().getName());
        try {
            TimeUnit.MILLISECONDS.sleep(2000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
    
    @Async("getAsyncExecutor")
    public Future<Integer> asyncProcessHasReturn() {
        log.info("async process task (has return), current thread name -> {}", Thread.currentThread().getName());
        try {
            TimeUnit.MILLISECONDS.sleep(2000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return new AsyncResult<>(100);
    }
}

@Async("getAsyncExecutor") 这里指定我们需要用到的线程池, 将会在下一个步骤配置

编写异步线程池配置

package com.imooc.springboot.study.config;

import com.alibaba.fastjson.JSON;
import lombok.extern.slf4j.Slf4j;
import org.springframework.aop.interceptor.AsyncUncaughtExceptionHandler;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.AsyncConfigurer;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

import java.lang.reflect.Method;
import java.util.concurrent.Executor;
import java.util.concurrent.ThreadPoolExecutor;

/**
 * 自定义异步线程池配置
 *
 * @author sunchangheng
 */
@Slf4j
@Configuration
public class AsyncConfig implements AsyncConfigurer {
    
    @Bean
    @Override
    public Executor getAsyncExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        
        // 线程池核心的数量, 默认是1, 导致异步线程池无法被重用
        executor.setCorePoolSize(10);
        executor.setMaxPoolSize(20);
        executor.setQueueCapacity(20);
        executor.setKeepAliveSeconds(60);
        executor.setThreadNamePrefix("ImoocAsync_");
        
        // 是否等待所有线程执行完毕之后才去关闭线程池, 默认是false
        executor.setWaitForTasksToCompleteOnShutdown(true);
        // 和上面这个参数一起使用, 等待60s
        executor.setAwaitTerminationSeconds(60);
        
        // 拒绝策略
        // 就是线程池满了, 怎么处理的策略
        executor.setRejectedExecutionHandler(
                // 直接抛出异常
                new ThreadPoolExecutor.AbortPolicy());
        
        executor.initialize();
        
        return executor;
    }
    
    /**
     * 定义异步任务异常处理类 1. 没有返回值的异步任务, 的异常将会在这里抛出 2. 有返回值的异步任务, 异常将会抛出给上一层
     */
    @Override
    public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
        
        return new AsyncExceptionHandler();
    }
    
    static class AsyncExceptionHandler implements AsyncUncaughtExceptionHandler {
        
        @Override
        public void handleUncaughtException(Throwable throwable, Method method, Object... objects) {
            log.info("Async: {}, method: {}, param: {}",
                    throwable.getMessage(),
                    method.getName(),
                    JSON.toJSONString(objects));
            
            throwable.printStackTrace();
            
            // todo 发送邮件或者短信给相关负责人...
        }
    }
}

注意: getAsyncExecutor这个方法一定要加上@Bean

单元测试

package com.imooc.springboot.study.service;

import com.imooc.springboot.study.async.AsyncService;
import lombok.extern.slf4j.Slf4j;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import javax.annotation.Resource;
import java.util.concurrent.Future;

@Slf4j
@SpringBootTest
@RunWith(SpringRunner.class)
public class AsyncServiceTest {
    @Resource
    private AsyncService asyncService;
    
    @Test
    public void testAsyncProcess() {
        asyncService.asyncProcess();
        log.info("testAsyncProcess end...");
    }
    
    @Test
    public void testAsyncProcessHasReturn() throws Exception {
        long start = System.currentTimeMillis();
        Future<Integer> result = asyncService.asyncProcessHasReturn();
        log.info("异步任务返回值: {}", result.get());
        log.info("测试用例执行了: {} ms", System.currentTimeMillis() - start);
    }
}

注意一定要加这两个注解: @SpringBootTest @RunWith(SpringRunner.class)

开机启动

方式一

package com.imooc.springboot.study.runer;

import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

/**
 * 1. SpringBoot 开机启动
 * @author sunchangheng
 */
@Order(2)
@Slf4j
@Component
public class BootApplicationRunner implements ApplicationRunner {
    
    @Override
    public void run(ApplicationArguments args) throws Exception {
        log.info("this is BootApplicationRunner ...");
    }
}

方式二

package com.imooc.springboot.study.runer;

import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.CommandLineRunner;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

/**
 * 2. SpringBoot开机启动
 * @author sunchangheng
 */
@Order(1)
@Slf4j
@Component
public class BootCommandLineRunner implements CommandLineRunner {
    
    
    @Override
    public void run(String... args) throws Exception {
        log.info("this is BootCommandLineRunner ...");
    }
}

注意

默认ApplicationRunner 的启动优先级大于CommandLineRunner
可以使用Order 定义启动顺序, 值越小优先级越高

Json使用技巧

Java 实体类

package com.imooc.springboot.study.vo;

import com.fasterxml.jackson.annotation.JsonFormat;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.annotation.JsonProperty;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.util.Date;

/**
 * 用户
 * @author sunchangheng
 */
@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
@JsonIgnoreProperties({"remark", "desc"})
public class Imoocer {
    private String name;
    
    private Integer age;
    
    @JsonIgnore
    private String address;
    
    @JsonProperty("rt")
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    private Date registerTime;
    
    private String remark;
    
    private String desc;

}

注意

JsonIgnoreProperties  # 在类上注释, 可以忽略多个不想序列化的字段
JsonProperty  # 序列化时, 会将registerTime 改变成 rt
JsonIgnore  # 注释在属性上, 当前属性将不会被序列化
JsonFormat  # Date的序列化格式

Json全局配置

package com.imooc.springboot.study.config;

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.text.SimpleDateFormat;

/**
 * Json的配置类
 * @author sunchangheng
 */
@Configuration
public class JacksonConfig {
    
    @Bean
    public ObjectMapper getObjectMapper() {
        ObjectMapper mapper = new ObjectMapper();
        // 空值不做序列化处理
        mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
        // 序列化的时间格式
        mapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));
        return mapper;
    }
}

controller序列化与反序列化测试

package com.imooc.springboot.study.controller;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.imooc.springboot.study.config.SpringBootConfig;
import com.imooc.springboot.study.vo.Imoocer;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;
import java.io.IOException;
import java.util.Date;

/**
 * @author sunchangheng
 */
@Slf4j
@RestController
@RequestMapping("/springboot")
public class TestController     
    @Resource
    private ObjectMapper mapper
    
    /**
     * 功能描述: Json序列化与反序列化测试
     * 127.0.0.1:8000/imooc/springboot/jackson
     */
    @GetMapping("/jackson")
    public Imoocer jackson() throws IOException {
        Imoocer imoocer = Imoocer.builder().name("qinyi").age(19).remark("hello world").desc("什么")
                .registerTime(new Date()).build();
    
        // 序列化: object->json
        String jsonImoocer = mapper.writeValueAsString(imoocer);
    
        // 反序列化: json->object
        return mapper.readValue(jsonImoocer, Imoocer.class);
    }
}

Actuator监控

// /actuator/info 默认返回空
// 可以在配置文件配置info

简单使用

<!-- Actuator监控 -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

配置文件

# Actuator监控相关
management:
  endpoint:
    shutdown:
      enabled: true  # 最特殊的控制断点, 远程关闭应用程序的断点, 比较危险, 一般不打开

  endpoints:
    web:
      exposure:
        include:  "*" # 打开所有断点

# /imooc/actuator
# http://127.0.0.1:8000/imooc/actuator/health
# http://127.0.0.1:8000/imooc/actuator/info

info:
  app:
    name: imooc-springboot-study
    groupId: com.imooc.springboot.study
    version: 1.0-SNAPSHOT

自定义监控端点

自定义端点

package com.imooc.springboot.study.endpoint;

import org.springframework.boot.actuate.endpoint.annotation.Endpoint;
import org.springframework.boot.actuate.endpoint.annotation.ReadOperation;
import org.springframework.boot.actuate.endpoint.annotation.WriteOperation;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

/**
 * 自定义事件端点 127.0.0.1:8000/imooc/actuator/datetime
 *
 * @author sunchangheng
 */
@Endpoint(id = "datetime")
public class DateTimeEndpoint {
    
    private String fmt = "yyyy-MM-dd HH:mm:ss";
    
    /**
     * 功能描述: 用来显示监控指标
     * get   http://127.0.0.1:8000/imooc/actuator/datetime
     */
    @ReadOperation
    public Map<String, Object> info() {
        Map<String, Object> info = new HashMap<>(10);
        info.put("name", "sch");
        info.put("age", 19);
        info.put("dt", new SimpleDateFormat(fmt).format(new Date()));
        return info;
    }
    
    /**
     * 功能描述: 动态更改监控指标
     * post  http://127.0.0.1:8000/imooc/actuator/datetime
     */
    @WriteOperation
    public void setFormat(String format) {
        this.fmt = format;
    }
}

启用自定义配置的端点

package com.imooc.springboot.study.endpoint;

import org.springframework.boot.actuate.autoconfigure.endpoint.condition.ConditionalOnEnabledEndpoint;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * 自定义端点配置类
 *
 * @author sunchangheng
 */
@Configuration
public class DateTimeEndpointConfig {
    
    @Bean
    @ConditionalOnMissingBean
    @ConditionalOnEnabledEndpoint
    public DateTimeEndpoint dateTimeEndpoint() {
        return new DateTimeEndpoint();
    }
}

注意: 需要在配置文件中打开所有端点

自定义 Starter

新建一个starter项目

依赖

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-configuration-processor</artifactId>
        <version>2.1.4.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-autoconfigure</artifactId>
        <version>2.1.4.RELEASE</version>
    </dependency>
</dependencies>

创建service

接口

package com.imooc.springboot.service;

import java.util.List;

/**
 * @author sunchangheng
 */
public interface ISplictService {
    
    /**
     * 功能描述: 分割字符串
     * @param str 将要分割的字符串
     * @return 字符串列表
     */
    List<String> split(String str);

}

实现

package com.imooc.springboot.service.impl;

import com.imooc.springboot.service.ISplictService;
import org.springframework.util.StringUtils;

import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;

/**
 * @author sunchangheng
 */
public class SplictServiceImpl implements ISplictService {
    
    @SuppressWarnings("all")
    @Override
    public List<String> split(String str) {
        return Stream.of(StringUtils.split(str, ",")).collect(Collectors.toList());
    }
}

配置自动注入

package com.imooc.springboot.configure;

import com.imooc.springboot.service.ISplictService;
import com.imooc.springboot.service.impl.SplictServiceImpl;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * @author sunchangheng
 */
@Configuration
@ConditionalOnClass({ISplictService.class, SplictServiceImpl.class})
public class SplictAutoConfigure {
    
    @Bean
    @ConditionalOnMissingBean
    ISplictService starterService() {
        return new SplictServiceImpl();
    }
}

配置meta-inf

org.springframework.boot.autoconfigure.EnableAutoConfiguration=com.imooc.springboot.configure.SplictAutoConfigure

maven 打包到本地 mvn install
最后就可以在其他项目引入使用了

在其他项目引入使用

引入依赖

<dependency>
    <groupId>com.imooc.springboot</groupId>
    <artifactId>split-spring-boot-starter</artifactId>
    <version>1.0-SNAPSHOT</version>
</dependency>

使用测试用例测试

package com.imooc.springboot.study.service;

import com.alibaba.fastjson.JSON;
import com.imooc.springboot.service.ISplictService;
import com.imooc.springboot.study.config.SpringBootConfig;
import lombok.extern.slf4j.Slf4j;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import javax.annotation.Resource;

@Slf4j
@SpringBootTest
@RunWith(SpringRunner.class)
public class SplictServiceTest {
    @Resource
    private ISplictService splictService;
    
    @Resource
    private SpringBootConfig springBootConfig;
    
    @Test
    public void testSplictVersion() {
        log.info("splict version: {}", JSON.toJSONString(splictService.split(springBootConfig.getVersion())));
    }
}

管理 SpringBoot 应用

# 打包到target目录
mvn clean package -Dmaven.test.skip=true -U

启动脚本

# start.sh
#!/usr/bin/env bash
nohup java -jar imooc-springboot-study.jar &

停止脚本

#!/usr/bin/env bash

pid=`ps -ef | grep imooc-springboot-study.jar | grep -v grep | awk '{print $2}'`

if [[ -z "${pid}"]]
then
  echo application is already stopped
else
  echo kill ${pid}
  kill -9 ${pid}
fi

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原文地址：https://www.cnblogs.com/sunch/p/15088095.html