Spring Boot学习笔记

Maven创建Spring Boot的方法

在某些情况下，start.spring.io无法访问时，可以直接使用Maven创建Spring Boot项目

  1. 新建Maven项目

  2. 在pom.xml文件中添加parent节点

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    <parent>    
        <groupId>org.springframework.boot</groupId>    
        <artifactId>spring-boot-starter-parent</artifactId>    	        
        <version>2.3.0.RELEASE</version>
    </parent>

  3. 添加spring-boot-starter-web和spring-boot-starter-test依赖

  4. 添加spring-boot-maven-plugin插件

  5. 创建启动类

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

HttpMessageConverter

在Spring MVC中自动配置了Jackson和Gson的HttpMessageConverter

  1. 将服务端返回的对象序列化成JSON字符串
  2. 将前端传递的JSON字符串反序列化成Java对象

自定义HttpMessageConverter的方式

  • Jackson

  1. 提供MappingJackson2HttpMessageConverter的bean

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    @Bean
    MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter() {   
        MappingJackson2HttpMessageConverter converter = new 	
    MappingJackson2HttpMessageConverter();      
        ObjectMapper om = new ObjectMapper();   
        om.setDateFormat(new SimpleDateFormat("yyyy/MM/dd hh:mm:SSS"));  
        converter.setObjectMapper(om); 
        return converter;
    }
    //起主要作用的是ObjectMapper

  2. 提供ObjectMapper

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    @Bean
    ObjectMapper objectMapper() {
    	ObjectMapper om = new ObjectMapper();
    	om.setDateFormat(new SimpleDateFormat("yyyy/MM/dd hh/mm/SSS"));
    	return om;
    }
  • Gson

  1. 修改spring-boot-starter-web中默认的Jackson依赖，添加Gson依赖

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    <dependency>
    	<groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
        <exclusions>
    		<exclusion>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-json</artifactId>
    		</exclusion>
    	</exclusions>
    </dependency>
    <dependency>
    	<groupId>com.google.code.gson</groupId>
    	<artifactId>gson</artifactId>
    </dependency>

  2. 提供GsonHttpMessageConverter的bean

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    @Bean
    GsonHttpMessageConverter gsonHttpMessageConverter(){
    	GsonHttpMessageConverter converter = new GsonHttpMessageConverter();
    	converter.setGson(new 
        GsonBuilder().setDateFormat("yyyy/MM/dd").create());
    	return converter;
    }
    //起主要作用的是Gson

  3. 提供Gson

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    @Bean
    Gson gson(){
    	return new GsonBuilder().setDateFormat("yyyy/MM/dd").create();
    }
  • FastJson

  1. 修改spring-boot-starter-web中默认的Jackson依赖，添加Fastjson依赖

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    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
        <exclusions>
            <exclusion>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-json</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>fastjson</artifactId>
        <version>1.2.68</version>
    </dependency>

  2. 提供FastJsonHttpMessageConverter

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    @Bean
    FastJsonHttpMessageConverter fastJsonHttpMessageConverter(){
        FastJsonHttpMessageConverter converter = new 		
    FastJsonHttpMessageConverter();
        FastJsonConfig fastJsonConfig = new FastJsonConfig();
        fastJsonConfig.setDateFormat("yyyy/MM/dd");
        converter.setFastJsonConfig(fastJsonConfig);
        return converter;
    }

静态资源的访问

在Spring Boot的WebMvcAutoConfiguration中已经默认设置了五个静态资源的访问路径，按优先级顺序依次为META-INF/resources、resources、static、public、/。

自定义静态资源的位置

  1. 在application.properties中添加

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    spring.resources.static-locations=classpath:/xxx/
    # 也可以添加规则
    spring.mvc.static-path-pattern=/**

  2. 在Java类中配置

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    @Configuration
    public class WebMVCConfig implements WebMvcConfigurer {
    	@Override
    	public void addResourceHandlers(ResourceHandlerRegistry registry) {
    		registry.addResourceHandler("/**").addResourceLocations("classpath:/xxx/");
    	}
    }

文件上传

主要使用MultipartFile类

  1. 创建Controller

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    @RestController
    public class FileUploadController {
    	SimpleDateFormat sdf = new SimpleDateFormat("/yyyy/MM/dd/");

    	@PostMapping("/upload")
    	public String upload(MultipartFile file, HttpServletRequest req) {
    		String format = sdf.format(new Date());
    		String realPath = req.getServletContext().getRealPath("/img") + format;
    		File folder = new File(realPath);
    		if (!folder.exists()) {
    			folder.mkdirs();
    		}
    		String oldName = file.getOriginalFilename();
    		String newName = UUID.randomUUID().toString() + oldName.substring(oldName.lastIndexOf("."));
    		try {
    			file.transferTo(new File(realPath, newName));
    			String url = req.getScheme() + "://" + req.getServerName() + ":" + req.getServerPort() + "/img" + format + newName;
    			return url;
    		} catch (IOException e) {
    			e.printStackTrace();
    		}
    		return "error";
    	}
    }

  2. 创建index.html

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    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Title</title>
    </head>
    <body>
    <form action="/upload" method="post" enctype="multipart/form-data">
        <input type="file" name="file">
        <input type="submit" value="submit">
    </form>
    </body>
    </html>

  3. 关于上传文件大小的限制需要在application.properties中进行修改

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    spring.servlet.multipart.max-file-size=1MB

@ControllerAdvice

  • 全局异常处理

    1. 创建MyCustomException

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      @ControllerAdvice
      public class MyCustomException {
          //以response的方式返回
      	@ExceptionHandler(MaxUploadSizeExceededException.class)
      	public void myException(MaxUploadSizeExceededException e, HttpServletResponse res) throws IOException {
      		res.setContentType("text/html;charset=utf-8");
      		PrintWriter out = res.getWriter();
      		out.write("上传文件大小超出限制!");
      		out.flush();
      		out.close();
      	}

          //以视图的方式返回
      	@ExceptionHandler(MaxUploadSizeExceededException.class)
      	public ModelAndView myException(MaxUploadSizeExceededException e) throws IOException {
      		ModelAndView modelAndView = new ModelAndView("myerror");
      		modelAndView.addObject("error", "文件大小超过限制！");
      		return modelAndView;
      	}
      }

    2. 以ModelAndView的方式返回需要创建错误页面myerror.html以及thymeleaf的依赖

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      <!DOCTYPE html>
      <head xmlns:th="http://www.thymeleaf.org">
          <meta charset="UTF-8">
          <title>Title</title>
      </head>
      <body>
      	<h1 th:text="${error}"></h1>
      </body>
      </html>

  • 预设全局数据

    1. 创建全局数据类，使用Map保存数据

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      @ControllerAdvice
      public class GlobalData {
      	@ModelAttribute(value = "person")
      	public Map<String,Object> mydata(){
      		Map<String,Object> map = new HashMap<>();
      		map.put("name","wan");
      		map.put("gender","male");
      		return map;
      	}
      }

    2. 在Controller中使用Model调用数据

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      @RestController
      public class HelloController {
      	@GetMapping("/hello")
      	public String hello(Model model){
      		Map<String, Object> map = model.asMap();
      		Set<String> keySet = map.keySet();
      		for (String s : keySet) {
      			System.out.println(s+":"+map.get(s));
      		}
      		return "hello";
      	}
      }

  • 请求参数预处理

现在出现如下需求，前端向后端发送请求参数时出现命名冲突：

key value
name 三国演义
price 99
name 吴冠中
age 100

此时在服务器端接受的数据会有问题，解决方法如下：

  1. 给接收参数重命名

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    @RestController
    public class BookController {
    	@PostMapping("/book")
    	public void addBook(@ModelAttribute("b") Book book, @ModelAttribute("a") Author author){
    		System.out.println(book);
    		System.out.println(author);
    	}
    }

  2. 创建@ControllerAdvice类

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    @InitBinder(value = "a")
    public void initA(WebDataBinder binder){
        binder.setFieldDefaultPrefix("a.");
    }

    @InitBinder(value = "b")
    public void initB(WebDataBinder binder){
        binder.setFieldDefaultPrefix("b.");
    }

@ModelAttribute

WebDataBinder

@InitBinder

ControllerAdvice

Model

ModelAndView

@ExceptionHandler

自定义异常

  1. 在classpath下的static和template目录中创建error目录并创建静态错误页面和动态错误页面，按优先级依次访问：精确大于模糊，动态大于静态

  2. 自定义错误数据

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    @Component
    public class MyErrorConfig extends DefaultErrorAttributes {
    	@Override
    	public Map<String, Object> getErrorAttributes(WebRequest webRequest, ErrorAttributeOptions options) {
    		Map<String, Object> errorAttributes = super.getErrorAttributes(webRequest, options);
    		errorAttributes.put("myerror","自定义异常信息！");
    		return errorAttributes;
    	}
    }

  3. 自定义错误视图

    1. 自定义ErrorViewResolver继承自DefaultErrorViewResolver
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    @Component
    public class MyErrorViewResolver extends DefaultErrorViewResolver {
    	/**
    	 * Create a new {@link DefaultErrorViewResolver} instance.
    	 *
    	 * @param applicationContext the source application context
    	 * @param resourceProperties resource properties
    	 */
    	public MyErrorViewResolver(ApplicationContext applicationContext, ResourceProperties resourceProperties) {
    		super(applicationContext, resourceProperties);
    	}

    	@Override
    	public ModelAndView resolveErrorView(HttpServletRequest request, HttpStatus status, Map<String, Object> model) {
    		ModelAndView modelAndView = super.resolveErrorView(request, status, model);
    		modelAndView.setViewName("myerror");
    		modelAndView.addObject(model);
    		return modelAndView;
    	}
    }
    1. 自定义视图myerror.html

ErrorMvcAutoConfiguration

DefaultErrorAttributes

getErrorAttributes()

DefaultErrorViewResolver

resolveErrorView()

CORS解决跨域问题

  1. 在请求中添加注解@CrosOrigin(origins = "http://xxxx:xxxx")即可

  2. 创建配置类

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    @Configuration
    public class MyMVCConfig implements WebMvcConfigurer {
    	@Override
    	public void addCorsMappings(CorsRegistry registry) {
    		registry.addMapping("/**")
    				.allowedOrigins("http://xxxx:xxxx")
    				.allowedHeaders("*")
    				.allowedMethods("*");
    	}
    }

WebMvcConfigurer

addCorsMappings(CorsRegistry registry)

XML

  1. 创建beans.xml

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    <?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 class="org.wan.xml.Hello" id="hello"/>
    </beans>

  2. 创建MyWebNvcConfig

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    @Configuration
    @ImportResource(locations = "classpath:beans.xml")
    public class WebMvcConfig {
    }

注册拦截器

  1. 自定义Interceptor

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    public class MyInterceptor implements HandlerInterceptor {
    	@Override
    	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
    		System.out.println("preHandle");
    		return true;
    	}

    	@Override
    	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
    		System.out.println("postHandle");
    	}

    	@Override
    	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
    		System.out.println("afterCompletion");
    	}
    }

  2. 创建WebMvcConfig

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    @Configuration
    public class WebMvcConfig implements WebMvcConfigurer {
    	@Override
    	public void addInterceptors(InterceptorRegistry registry) {
    		registry.addInterceptor(myInterceptor()).addPathPatterns("/**");
    	}

    	@Bean
    	MyInterceptor myInterceptor(){
    		return new MyInterceptor();
    	}
    }

定义系统启动任务

  1. CommandLineRunner

    • 创建MyCommanderLineRunner

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      @Component
      @Order(1)
      public class MyCommandLineRunner1 implements CommandLineRunner {
      	@Override
      	public void run(String... args) throws Exception {

      	}
      }

      @Component
      @Order(2)
      public class MyCommandLineRunner2 implements CommandLineRunner {
      	@Override
      	public void run(String... args) throws Exception {

      	}
      }
      //order表示优先级，值越小优先级越高

  2. ApplicationRunner(获取参数的类型更丰富)

    • 创建MyApplicationRunner

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      @Component
      @Order(2)
      public class MyApplicationRunner1 implements ApplicationRunner {
      	@Override
      	public void run(ApplicationArguments args) throws Exception {

      	}
      }

      @Component
      @Order(1)
      public class MyApplicationRunner2 implements ApplicationRunner {
      	@Override
      	public void run(ApplicationArguments args) throws Exception {

      	}
      }

CommandLineRunner

ApplicationRunner

类型转换器

需求：前端向后端传递日期的字符串，后端使用Date对象无法接收，此时需要自定义转换器

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@Component
public class MyConverter implements Converter<String, Date> {
	SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");

	@Override
	public Date convert(String s) {
		if (s != null) {
			try {
				return sdf.parse(s);
			} catch (ParseException e) {
				e.printStackTrace();
			}
		}
		return null;
	}
}

AOP

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@Component
@Aspect
public class MyLogger {
	@Pointcut("execution(* org.wan.aop.service.*.*(..))")
	public void pc1() {
	}

	@Before(value = "pc1()")
	public void before(JoinPoint jp) {
		String name = jp.getSignature().getName();
		System.out.println("before:" + name);
	}

	@After(value = "pc1()")
	public void after(JoinPoint jp) {
		String name = jp.getSignature().getName();
		System.out.println("after:" + name);
	}

	@AfterReturning(value = "pc1()",returning = "result")
	public void afterReturning(JoinPoint jp, Object result) {
		String name = jp.getSignature().getName();
		System.out.println("afterReturning:" + name+"----"+result);
	}

	@Around("pc1()")
	public Object around(ProceedingJoinPoint pjp) throws Throwable {
		return pjp.proceed();
	}

	@AfterThrowing(value = "pc1()",throwing = "e")
	public void afterThrowing(JoinPoint jp,Exception e) {
		String name = jp.getSignature().getName();
		System.out.println("afterThrowing:" + name+"----"+e.getMessage());
	}
}

@Aspect

@Pointcut(“execution( org.wan.aop.service..*(..))”)

@Before(value = “pc1()”)

@After(value = “pc1()”)

@AfterReturning(value = “pc1()”,returning = “result”)

@Around(“pc1()”)

@AfterThrowing(value = “pc1()”,throwing = “e”)

JdbcTemplate

  1. 依赖

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    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jdbc</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid-spring-boot-starter</artifactId>
        <version>1.1.10</version>
    </dependency>

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <scope>runtime</scope>
        <version>8.0.16</version>
    </dependency>

  1. MySQL配置

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    spring.datasource.one.url=jdbc:mysql://localhost:3306/test1?characterEncoding=utf8&useSSL=true&serverTimezone=UTC&zeroDateTimeBehavior=CONVERT_TO_NULL
    spring.datasource.one.username=root
    spring.datasource.one.password=123456
    spring.datasource.one.type=com.alibaba.druid.pool.DruidDataSource


    spring.datasource.two.url=jdbc:mysql://localhost:3306/test2?characterEncoding=utf8&useSSL=true&serverTimezone=UTC&zeroDateTimeBehavior=CONVERT_TO_NULL
    spring.datasource.two.username=root
    spring.datasource.two.password=123456
    spring.datasource.two.type=com.alibaba.druid.pool.DruidDataSource

  2. 自定义DataSource

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    @Configuration
    public class DataSourceConfig {
    	@Bean
    	@ConfigurationProperties(prefix = "spring.datasource.one")
    	DruidDataSource dsOne(){
    		return DruidDataSourceBuilder.create().build();
    	}

    	@Bean
    	@ConfigurationProperties(prefix = "spring.datasource.two")
    	DruidDataSource dsTwo(){
    		return DruidDataSourceBuilder.create().build();
    	}
    }

  3. 自定义JdbcTemplate

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    @Configuration
    public class JdbcTemplateConfig {

    	@Bean
    	JdbcTemplate jdbcTemplateOne(@Qualifier("dsOne") DataSource ds){
    		return new JdbcTemplate(ds);
    	}

    	@Bean
    	JdbcTemplate jdbcTemplateTwo(@Qualifier("dsTwo") DataSource ds){
    		return new JdbcTemplate(ds);
    	}
    }

@ConfigurationProperties(prefix = “spring.datasource.one”)

DruidDataSource

DruidDataSourceBuilder.create().build()

JdbcTemplate

@Qualifier(“dsOne”) DataSource ds

MyBatis

  1. 添加依赖以及配置resource

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    <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>2.1.2</version>
    </dependency>

    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid-spring-boot-starter</artifactId>
        <version>1.1.10</version>
    </dependency>

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <scope>runtime</scope>
        <version>8.0.16</version>
    </dependency>

    <!--添加resource的目的在于，将mapper.xml和对应的Mapper.java文件放在同一个package下-->
    <!--也可以在resource目录下创建和对应Mapper.java相同路径的mapper.xml-->
    <!--也可以将mapper.xml放于resource中的文件夹中，然后在application.properties中设置mybatis.mapper-locations=classpath:/mapper/*.xml-->
    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
            </resource>
        </resources>
    </build>

  1. MySQL配置

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    spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
    spring.datasource.username=root
    spring.datasource.password=123456
    spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
    spring.datasource.url=jdbc:mysql://localhost:3306/test1?characterEncoding=utf8&useSSL=true&serverTimezone=UTC&zeroDateTimeBehavior=CONVERT_TO_NULL

  2. 配置mapper.xml和mapper.java

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    <?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
    <mapper namespace="com.example.mybatis.mapper.UserMapper">
        <select id="getAllUser" resultType="com.example.mybatis.bean.User">
            select * from user;
        </select>
    </mapper>
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    public interface UserMapper {
    	List<User> getAllUser();
    }

  3. 配置多数据源

    • 配置数据源

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      spring.datasource.one.type=com.alibaba.druid.pool.DruidDataSource
      spring.datasource.one.username=root
      spring.datasource.one.password=123456
      spring.datasource.one.url=jdbc:mysql://localhost:3306/test1?characterEncoding=utf8&useSSL=true&serverTimezone=UTC&zeroDateTimeBehavior=CONVERT_TO_NULL

      spring.datasource.two.type=com.alibaba.druid.pool.DruidDataSource
      spring.datasource.two.username=root
      spring.datasource.two.password=123456
      spring.datasource.two.url=jdbc:mysql://localhost:3306/test2?characterEncoding=utf8&useSSL=true&serverTimezone=UTC&zeroDateTimeBehavior=CONVERT_TO_NULL

    • 创建mapper1和mapper2两个package，在各自包下创建mapper.xml和mapper.java

    • 创建自定义DataSource

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      @Configuration
      public class DataSourceConfig {

      	@Bean
      	@ConfigurationProperties(prefix = "spring.datasource.one")
      	DataSource dataSourceOne(){
      		return DruidDataSourceBuilder.create().build();
      	}

      	@Bean
      	@ConfigurationProperties(prefix = "spring.datasource.two")
      	DataSource dataSourceTwo(){
      		return DruidDataSourceBuilder.create().build();
      	}
      }

    • 创建配置类MyBatisConfigOne和MyBatisConfigTwo

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      @Configuration
      @MapperScan(basePackages = "com.example.mybatis.mapper1",sqlSessionFactoryRef = "sqlSessionFactory1",
      		sqlSessionTemplateRef = "sqlSessionTemplate1")
      public class MyBatisConfigOne {
      	@Resource(name = "dataSourceOne")
      	DataSource dsOne;

      	@Bean
      	SqlSessionFactory sqlSessionFactory1(){
      		SqlSessionFactoryBean ssfb = new SqlSessionFactoryBean();
      		ssfb.setDataSource(dsOne);
      		try {
      			return ssfb.getObject();
      		} catch (Exception e) {
      			e.printStackTrace();
      		}
      		return null;
      	}

      	@Bean
      	SqlSessionTemplate sqlSessionTemplate1(){
      		return new SqlSessionTemplate(sqlSessionFactory1());
      	}
      }
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      @Configuration
      @MapperScan(basePackages = "com.example.mybatis.mapper2",sqlSessionFactoryRef = "sqlSessionFactory2",
      		sqlSessionTemplateRef = "sqlSessionTemplate2")
      public class MyBatisConfigTwo {
      	@Resource(name = "dataSourceTwo")
      	DataSource dsTwo;

      	@Bean
      	SqlSessionFactory sqlSessionFactory2(){
      		SqlSessionFactoryBean ssfb = new SqlSessionFactoryBean();
      		ssfb.setDataSource(dsTwo);
      		try {
      			return ssfb.getObject();
      		} catch (Exception e) {
      			e.printStackTrace();
      		}
      		return null;
      	}

      	@Bean
      	SqlSessionTemplate sqlSessionTemplate2(){
      		return new SqlSessionTemplate(sqlSessionFactory2());
      	}
      }
src/main/java **/*.xml src/main/resources

@MapperScan(basePackages = “com.example.mybatis.mapper1”,sqlSessionFactoryRef = “sqlSessionFactory1”,
sqlSessionTemplateRef = “sqlSessionTemplate1”)

SqlSessionFactory

SqlSessionTemplate

JPA

  1. 依赖

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    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid-spring-boot-starter</artifactId>
        <version>1.1.10</version>
    </dependency>

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <scope>runtime</scope>
        <version>8.0.16</version>
    </dependency>

  2. MySQL配置

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    spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
    spring.datasource.url=jdbc:mysql://localhost:3306/test1?characterEncoding=utf8&useSSL=true&serverTimezone=UTC&zeroDateTimeBehavior=CONVERT_TO_NULL
    spring.datasource.username=root
    spring.datasource.password=123456
    spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver


    spring.jpa.show-sql=true
    spring.jpa.database=mysql
    spring.jpa.database-platform=mysql
    spring.jpa.hibernate.ddl-auto=update
    spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL57Dialect

  3. 创建bean

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    @Entity(name = "t_book")
    public class Book {
    	@Id
    	@GeneratedValue(strategy = GenerationType.IDENTITY)
    	private Integer id;
    	private String name;
    	private String author;
    }

  4. 创建dao

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    public interface BookDao extends JpaRepository<Book,Integer> {
    }

spring.jpa.show-sql=true
spring.jpa.database=mysql
spring.jpa.database-platform=mysql
spring.jpa.hibernate.ddl-auto=update
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL57Dialect

@Entity(name = “t_book”)

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)

JpaRepository

Redis

Session

Nginx

MongoDB

Docker

RESTful