本文介绍: 1.默认包扫描规则:主程序所在的包及其下的子包都会被扫描2.SpringBoot帮我们配置好了所有的web开发的常用场景3.@SpringBootApplication等同于：4.默认配置最终都是映射到MultipartPropertiesSpringBoot先加载所有的自动配置类每个自动配置类按照条件进行生效，默认都会绑定配置文件默认的值生效的配置类就会给容器中装配很多组件只要容器中有了这些组件，就相当于这些功能就有了。只要自己配置了，就以自己的优先。
1.SpringBoot
1.1springboot是什么
1.2springboot的优点
2.Springboot入门
2.1版本控制
2.2创建maven工程
2.3导入父工程依赖
<parent>
<groupId>org.springframework.boot</groupId>
<version>2.7.14</version>
<artifactId>spring-boot-starter-parent</artifactId>
</parent>2.4添加springboot依赖
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>2.5创建主程序类
@SpringBootApplication
public class MainApplication {
public static void main(String[] args) {
SpringApplication.run(MainApplication.class,args);
}
}2.6controller
@RestController
public class HelloController {
@RequestMapping("/hello")
public String hello(){
return "hello,SprigBoot";
}
}2.7测试结果
2.8总结
2.SpringBoot帮我们配置好了所有的web开发的常用场景
@SpringBootConfiguration、@EnableAutoConfiguration、ComponentScan
3.相关注解的使用
3.1.@Configuration+@Bean
注意:
@Configuration（proxyBeanMethods = false）
public class MyConfig {
@Bean
public User user01() {
return new User("张三", "123456");
}
}3.2.@Import
@Import({User.class})
@Configuration
public class MyConfig {
@Bean
public User user01() {
return new User("张三", "123456");
}
} 
3.3.@ImprotResource
@ImportResource("classpath:bean.xml")
@Configuration
public class MyConfig {
@Bean
public User user01() {
return new User("张三", "123456");
}
}3.4.@ConfigurationProperties
3.5.@EnableConfigurationProperties
4.自动配置原理
@SpringBootApplication等价于：@SprignBootConfiguration+@EnableAutoConfiguration+@ComponentScan
4.1@SpringBootConfiguration
@Configuration
@Indexed
public @interface SpringBootConfiguration {
@AliasFor(
annotation = Configuration.class
)
boolean proxyBeanMethods() default true;
}4.2@ComponentScan
4.3@EnableAutoConfiguration
- 1.@Import:利用getAutoConfigurationEntry(annotationMetadata)給容器中批量导入一些组件.
- 2.调用List<String> configurations = getCandidateConfigurations(annotationMetadata, attributes)获取到所有导入到容器中的配置类.
- 3.利用工厂加载Map<String, List<String>> loadSpringFactories(@Nullable ClassLoader classLoader):得到所有的组件.
- 4.从META-INF/spring.factories位置来加载一个文件。默认扫描我们当前系统里面所有META-INF/spring.factories位置的文件spring–boot–autoconfigure-2.3.4.RELEASE.jar包里面也有META-INF/spring.factories.
@AutoConfigurationPackage
@Import({AutoConfigurationImportSelector.class})
public @interface EnableAutoConfiguration {
String ENABLED_OVERRIDE_PROPERTY = "spring.boot.enableautoconfiguration";
Class<?>[] exclude() default {};
String[] excludeName() default {};
}
4.4总结
5.简化开发
5.1Lombok
5.1.1导入依赖
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</dependency>5.1.2安装lombok插件
5.1.3实例
@Data
@ToString
@NoArgsConstructor
@AllArgsConstructor
public class User {
private String username;
private String password;
public User(String username) {
this.username = username;
}
}5.2dev–tools
spring为开发者提供了一个名为spring-boot-devtools的模块来使Spring Boot应用支持热部署。
5.2.1引入依赖
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<optional>true</optional>
</dependency>说明:ctrl+F9–重启,只要请求路径或类变化，无需重新部署。
5.3Spring Initailizr
5.3.1新建模块
5.3.2添加依赖项
5.3.3模块结构
5.4yaml
YAML 是 “YAML Ain’t Markup Language” (YAML 不是一种标记语言)的递归缩写。在开发的这种语言时，YAML 的意思其实是： “Yet Another Markup Language” (仍是一种标记语言）。
5.4.1基本语法
5.4.2数据类型
#或
k：
k1： v1
k2： v2
k3： v3
#或
k：
– v1
– v2
– v3
5.4.3实例
@ConfigurationProperties(prefix = "user")//与配置文件进行绑定
@Component //放到容器中
@Data
@ToString
@NoArgsConstructor
@AllArgsConstructor
public class User {
private String username;
private String pwd;
private String sex;
private Integer age;
private Pet pet;
}@ConfigurationProperties(prefix = "pet")
@Component
@Data
@ToString
@NoArgsConstructor
@AllArgsConstructor
public class Pet {
private String pName;
private Integer age;
}user:
username: jack
pwd: 123
sex: man
age: 18
loves:
- sql
- php
- java
pet:
pName: tom
age: 2
@RestController
public class HelloController {
@Autowired
private User user;
@RequestMapping("/user")
public User user(){
return user;
}
}结果:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-configuration-processor</artifactId>
</dependency>
注意:
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<excludes>
<exclude>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</exclude>
<exclude>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-configuration-processor</artifactId>
</exclude>
</excludes>
</configuration>
</plugin>
</plugins>
</build>6.Web开发
6.1静态资源访问
6.1.1.静态资源目录
6.1.2.静态资源访问前缀
6.1.3.欢迎页
6.1.4静态配置原理
@AutoConfiguration(
after = {DispatcherServletAutoConfiguration.class, TaskExecutionAutoConfiguration.class, ValidationAutoConfiguration.class}
)
@ConditionalOnWebApplication(
type = Type.SERVLET
)
@ConditionalOnClass({Servlet.class, DispatcherServlet.class, WebMvcConfigurer.class})
@ConditionalOnMissingBean({WebMvcConfigurationSupport.class})
@AutoConfigureOrder(-2147483638)
public class WebMvcAutoConfiguration {
public static final String DEFAULT_PREFIX = "";
public static final String DEFAULT_SUFFIX = "";
public static final PathPatternParser pathPatternParser = new PathPatternParser();
private static final String SERVLET_LOCATION = "/";WebMvcAutoConfiguration生效给容器中配置了什么呢？
@Configuration( proxyBeanMethods = false ) @Import({WebMvcAutoConfiguration.EnableWebMvcConfiguration.class}) @EnableConfigurationProperties({WebMvcProperties.class, WebProperties.class}) @Order(0) public static class WebMvcAutoConfigurationAdapter implements WebMvcConfigurer, ServletContextAware { private static final Log logger = LogFactory.getLog(WebMvcConfigurer.class); private final Resources resourceProperties; private final WebMvcProperties mvcProperties; private final ListableBeanFactory beanFactory; private final ObjectProvider<HttpMessageConverters> messageConvertersProvider; private final ObjectProvider<DispatcherServletPath> dispatcherServletPath; private final ObjectProvider<ServletRegistrationBean<?>> servletRegistrations; private final WebMvcAutoConfiguration.ResourceHandlerRegistrationCustomizer resourceHandlerRegistrationCustomizer; private ServletContext servletContext;
配置类只有一个有参构造器：有参构造器所有参数的值都会从容器中找
public WebMvcAutoConfigurationAdapter(WebProperties webProperties, WebMvcProperties mvcProperties, ListableBeanFactory beanFactory, ObjectProvider<HttpMessageConverters> messageConvertersProvider, ObjectProvider<WebMvcAutoConfiguration.ResourceHandlerRegistrationCustomizer> resourceHandlerRegistrationCustomizerProvider, ObjectProvider<DispatcherServletPath> dispatcherServletPath, ObjectProvider<ServletRegistrationBean<?>> servletRegistrations) { this.resourceProperties = webProperties.getResources(); this.mvcProperties = mvcProperties; this.beanFactory = beanFactory; this.messageConvertersProvider = messageConvertersProvider; this.resourceHandlerRegistrationCustomizer = (WebMvcAutoConfiguration.ResourceHandlerRegistrationCustomizer)resourceHandlerRegistrationCustomizerProvider.getIfAvailable(); this.dispatcherServletPath = dispatcherServletPath; this.servletRegistrations = servletRegistrations; this.mvcProperties.checkConfiguration(); }
- ResourceProperties resourceProperties;获取和spring.resources绑定的所有的值的对象
- WebMvcProperties mvcProperties获取和spring.mvc绑定的所有的值的对象
- ListableBeanFactory beanFactory Spring的beanFactory
- HttpMessageConverters 找到所有的HttpMessageConverters6 ResourceHandlerRegistrationCustomizer 找到 资源处理器的自定义器
- DispatcherServletPath8 //ServletRegistrationBean给应用注册Servlet、FilterI
public void addResourceHandlers(ResourceHandlerRegistry registry) { if (!this.resourceProperties.isAddMappings()) { logger.debug("Default resource handling disabled"); } else { this.addResourceHandler(registry, "/webjars/**", "classpath:/META-INF/resources/webjars/"); this.addResourceHandler(registry, this.mvcProperties.getStaticPathPattern(), (registration) -> { registration.addResourceLocations(this.resourceProperties.getStaticLocations()); if (this.servletContext != null) { ServletContextResource resource = new ServletContextResource(this.servletContext, "/"); registration.addResourceLocations(new Resource[]{resource}); } }); } }spring: web: resources: add-mappings: false
6.1.5rest风格
默认不开起
@Bean @ConditionalOnMissingBean({HiddenHttpMethodFilter.class}) @ConditionalOnProperty( prefix = "spring.mvc.hiddenmethod.filter", name = {"enabled"} ) public OrderedHiddenHttpMethodFilter hiddenHttpMethodFilter() { return new OrderedHiddenHttpMethodFilter(); }spring: mvc: hiddenmethod: filter: enabled: true
- 表单提交会带上_method=PUT
- 请求过来被HiddenHttpMethodFilter拦截
- 请求是否正常，并且是POST
- 获取到_method的值。兼容以下请求:PUT,DELETE,PATCH
- 原生request (post)，包装模式requesWrapper重写了getMethod方法，返回的是传入的值。
- 过滤器链放行的时候用wrapper,以后的方法调用getMethod是调用requesWrapper的。
<a href="/car/3/user/jack">测试@PathVarable</a>
6.2普通参数与基本注解
6.2.1@PathVarable
<a href="/car/3/user/jack">测试@PathVarable</a>@GetMapping("/car/{id}/user/{username}")
public Map<String, Object> getCar(@PathVariable("id") Integer id, @PathVariable("username") String username,) {
Map<String, Object> map = new HashMap<>();
map.put("id", id);
map.put("username", username);
return map;
}
6.2.2@RequestBody
<form action="/testPost" method="post">
用户名:<input type="text" name="username"><br>
密码: <input type="text" name="pwd"><br>
<input type="submit" value="提交"><br>
</form>@PostMapping("/testPost")
public Map<String,Object> postMethod(@RequestBody String content){
Map<String,Object> map=new HashMap<>();
map.put("content",content);
return map;
}
6.2.3@RequestAttribute
@RequestAttribute 获取请求域中的值
@GetMapping("/goTo")
public String goToPage(HttpServletRequest request) {
request.setAttribute("msg","小张");
request.setAttribute("code",200);
return "forward:/success";
}
@GetMapping("/success")
@ResponseBody
public Map<String, Object> success(@RequestAttribute("msg") String msg, @RequestAttribute("code") Integer code){
Map<String,Object> map=new HashMap<>();
map.put("msg",msg);
map.put("code",code);
return map;
}
6.2.4@MatrixVaribale
1.方式一:使用@Bean注解，给容器注入WebMvcConfigurer
@Configuration(proxyBeanMethods = false)
public class WebConfig {
@Bean
public WebMvcConfigurer webMvcConfigurer() {
return new WebMvcConfigurer() {
@Override
public void configurePathMatch(PathMatchConfigurer configurer) {
UrlPathHelper urlPathHelper = new UrlPathHelper();
//设置为不移除分号后面的内容，矩阵变量生效
urlPathHelper.setRemoveSemicolonContent(false);
configurer.setUrlPathHelper(urlPathHelper);
}
};
}
}2.方式二:实现接口WebMvcConfigurer
@Configuration(proxyBeanMethods = false)
public class WebConfig implements WebMvcConfigurer {
@Override
public void configurePathMatch(PathMatchConfigurer configurer) {
UrlPathHelper urlPathHelper = new UrlPathHelper();
//设置为不移除分号后面的内容，矩阵变量生效
urlPathHelper.setRemoveSemicolonContent(false);
configurer.setUrlPathHelper(urlPathHelper);
}
}3.测试情况一:无相同的请求属性
<a href="/cars/sell;low=34;brand=byd,bm,bc">测试@MatrixVarable</a> @ResponseBody
@GetMapping("/cars/{path}")
public Map<String, Object> carsSell(@MatrixVariable("low") Integer low,
@MatrixVariable("brand") List<String> brand,
@PathVariable("path") String path) {
Map<String, Object> map = new HashMap<>();
map.put("low", low);
map.put("brand", brand);
map.put("path", path);
return map;
}
3.测试情况二:相同的请求属性
<a href="/boss/1;id=10/2;id=20">测试@MatrixVarable=====情况二</a><br> @ResponseBody
@RequestMapping("/boss/{bossId}/{empId}")
public Map<String, Object> boss(@MatrixVariable(value = "id", pathVar = "bossId") Integer bossId,
@MatrixVariable(value = "id", pathVar = "empId") Integer empId) {
Map<String, Object> map = new HashMap<>();
map.put("bossId",bossId);
map.put("empId",empId);
return map;
}
6.3视图解析与模板引擎
6.3.1视图解析
6.3.2Thymeleaf使用
1.引入依赖
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>2.springboot已经自动配置好了thymeleaf
@AutoConfiguration(
after = {WebMvcAutoConfiguration.class, WebFluxAutoConfiguration.class}
)
@EnableConfigurationProperties({ThymeleafProperties.class})
@ConditionalOnClass({TemplateMode.class, SpringTemplateEngine.class})
@Import({ReactiveTemplateEngineConfiguration.class, DefaultTemplateEngineConfiguration.class})
public class ThymeleafAutoConfiguration {3.开发的页面存放位置
public class ThymeleafProperties {
private static final Charset DEFAULT_ENCODING;
public static final String DEFAULT_PREFIX = "classpath:/templates/";
public static final String DEFAULT_SUFFIX = ".html";4.实例
@Controller
public class ViewController {
@RequestMapping("/view")
public String view(Model model){
model.addAttribute("mgs","小张呀");
return "success";
}
}<html lang="en" xml:th="http://www.thymeleaf.org">
<!DOCTYPE html>
<html lang="en" xml:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>success</title>
</head>
<body>
<h1 th:text="${mgs}"></h1>
</body>
</html>
6.4拦截器
6.4.1.编写拦截器实现Handlerceptor接口
public class LoginInterceptor implements HandlerInterceptor {
/**
* 目标方法执行之前
*/
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
System.out.println("控制器方法执行前");
return false;
}
/**
* 目标方法执行以后
*/
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
System.out.println("控制器方法执行后");
}
/**
* 页面渲染以后
*/
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
System.out.println("视图渲染后");
}
}
6.4.2.拦截器注册到容器中
@Configuration
public class WebConfig {
/**
* 拦截器
*/
@Bean
public WebMvcConfigurer addInterceptors() {
return new WebMvcConfigurer() {
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(new LoginInterceptor())
.addPathPatterns("/**")//所有请求都会被拦截，包括静态资源
.excludePathPatterns("/");//放行的请求
}
};
}6.5文件上传
spring: servlet: multipart: max-file-size: 10MB max-request-size: 100MB
<form th:action="@{/form}" method="post" enctype="multipart/form-data">
头像:<input type="file" name="photo"><br>
<input type="submit" value="上传">
</form>@Controller
public class FormController {
@RequestMapping("/form")
public String form(@RequestPart("photo") MultipartFile photo) throws IOException {
if (!photo.isEmpty()) {
String filename = photo.getOriginalFilename();
photo.transferTo(new File("F:\" + filename));
}
return "form";
}
}6.6Web原生组件
2.使用@WebServlet注解
@WebServlet(urlPatterns = "/mv")
public class MyServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
resp.getWriter().write("9999");
}
}@ServletComponentScan(basePackages = "com.xz.demo_03")
@SpringBootApplication
public class Demo03Application {
public static void main(String[] args) {
SpringApplication.run(Demo03Application.class, args);
}
}7.数据访问
7.1数据源自动配置
自动配置的类：
- DataSourceAutoConfiguration:数据源的自动配置
1.导入jdbc场景
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jdbc</artifactId>
</dependency>
2.导入Mysql驱动
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.33</version>
</dependency>3.application.yml配置
spring:
datasource:
url: jdbc:mysql://localhost:3306/mybatis
password: 123456
username: root
driver-class-name: com.mysql.cj.jdbc.Driver
7.2使用Druid数据源
1.引入依赖
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid-spring-boot-starter</artifactId>
<version>1.2.16</version>
</dependency>2.自动配置分析
- 扩展配置项 spring.datasource.druid
- DruidSpringAopConfiguration.class,监控SpringBean的;配置项: spring.datasource.druid.aop–patterns
- DruidStatViewServletConfiguration.class,监控页的配置: spring.datasource.druid.stat-view–servlet;默认开启
- DruidWebStatFilterConfiguration.class, web监控配置; spring.datasource.druid.web-stat-filter;默认开启
- DruidFilterConfiguration.class))所有Druid自己filter的配置
3.application.yml
spring:
datasource:
url: jdbc:mysql://localhost:3306/mybatis
password: 123456
username: root
driver-class-name: com.mysql.cj.jdbc.Driver
druid:
stat-view-servlet:
enabled: true
login-username: admin
login-password: admin
reset-enable: false
web-stat-filter:
enabled: true
url-pattern: /*
exclusions: '*.jsp,*.gif,*.jpg,*.png,*.css,*.ioc,/druid/*'
7.3整合mybatis
1.引入依赖
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.3.1</version>
</dependency>2.配置模式
3.配置流程
#配置mybatis
mybatis:
# config-location: classpath:mybatis/mybatis-config.xml #全局配置文件位置，
#映射文件位置
mapper-locations: classpath:mybatis/mapper/*.xml
#指定 mybatis全局配置文件的相关配置
configuration:
#开启驼峰映射
map-underscore-to-camel-case: true4.实例
@Controller
@ResponseBody
public class UserController {
@Autowired
private UserService userService;
@GetMapping("/getAllUser")
public List<User> getUser(){
return userService.getAllUser();
}
}@Service
public class UserServiceImpl implements UserService {
@Autowired
private UserMapper userMapper;
@Override
public List<User> getAllUser() {
return userMapper.getAllUser();
}
}
dao:
注意@Mapper注解
@Mapper
public interface UserMapper {
/**
* 查询所有用户
* @return
*/
List<User> getAllUser();
}映射文件:
<mapper namespace="com.xz.mapper.UserMapper">
<select id="getAllUser" resultType="com.xz.pojo.User">
select * from t_user
</select>
</mapper>
5.纯注解Mybatis
mapper：直接在mapper的方法使用查询类型的注解@Select即可
@Mapper
public interface EmpMapper {
@Select("select * from t_emp")
List<Emp> getAllEmp();
}6.总结
@MapperScan("com.xz.mapper")
@SpringBootApplication
public class Demo04Application {
public static void main(String[] args) {
SpringApplication.run(Demo04Application.class, args);
}
}
原文地址:https://blog.csdn.net/dfdg345/article/details/134174496
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