SpringBoot常用配置（持续更新）

2023-10-17 09:52:40

自动装配原理

SpringBoot启动会加载大量的自动配置类xxxAutoConfiguration
xxxAutoConfiguration会使用@EnableConfigurationProperties注解绑定配置文件中的属性值
给容器中的自动配置类添加组件时,会从xxxProperties类中获取指定的属性值,只需要在配置文件中指定这些属性即可.
配置文件中的key和xxxProperties中@ConfigurationProperties注解的prefix属性值一一对应

pom.xml

spring-boot-dependencies ：核心依赖在父工程中

启动器starter ：Springboot的启动场景

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter</artifactId>
  <version>2.3.7.RELEASE</version>
</dependency>

比如spring-boot-starter-web，会自动导入web环境所有的依赖
springboot会将所有的功能场景，都变成一个个的启动器
要使用什么功能，就找到对应的启动器 starter

springboot的配置文件 application.yaml

通过查看原码（ResourceProperties类）
静态资源默认访问地址

classpath:/META-INF/resources/
classpath:/resources/
classpath:/static/
classpath:/public/

连接数据库，配置数据源

pom.xml引入相关依赖

  <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>8.0.27</version>
  </dependency>
  <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-jdbc</artifactId>
  </dependency>

application.yaml

spring:
  datasource:
    username: root
    password: 123456
    url: jdbc:mysql://localhost:3306?useUnicode=true&characterEncoding=utf-8
    driver-class-name: com.mysql.jdbc.Driver
    type: com.alibaba.druid.pool.DruidDataSource

测试

@SpringBootTest
class SpringbootTestApplicationTests {
    @Autowired
    DataSource dataSource;
    @Test
    void contextLoads() throws SQLException {
        System.out.println(dataSource.getClass());
        System.out.println(dataSource.getConnection());
    }
}

整合mybatis

pom.xml引入相关依赖

<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>1.3.2</version>
</dependency>

application.yaml

mybatis:
  type-aliases-package: com.hyj.pojo
  mapper-locations: classpath:mybatis/mapper/*.xml

Dao层使用Mapper注解，并DI注入到容器

@Mapper
@Repository
public interface UserMapper {
    public User queryById(@Param("id") int id);
}

Service层调用Dao层，并DI注入到容器

@Service
public class UserServiceImpl implements UserService{
    @Autowired
    private UserMapper userMapper;
    @Override
    public User queryById(int id) {
        return userMapper.queryById(id);
    }
}

mapper-locations:的文件夹下创建相对应xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.hyj.mapper.UserMapper">
    <select id="queryById" parameterType="int" resultType="user">
        select * from mybatis.user where id = #{id};
    </select>
</mapper>

测试

@SpringBootTest
class SpringbootTestApplicationTests {
    @Autowired
    private UserService userService;
    @Test
    void contextLoads() {
        System.out.println(userService.queryById(1));
    }
}

Druid 监控

@Configuration
public class DruidConfig {
    @ConfigurationProperties(prefix = "spring.datasource")
    @Bean
    public DataSource druidDataSource() {
        return new DruidDataSource();
    }
    //后台监控: web.xml
    @Bean
    public ServletRegistrationBean statViewServlet() {
        ServletRegistrationBean<StatViewServlet> bean = new ServletRegistrationBean<>(new StatViewServlet(), "/druid/*");

        HashMap<String, String> initParameters = new HashMap<>();
        //增加配置
        initParameters.put("loginUsername","admin");  //登录key 固定 loginUsername loginPassword
        initParameters.put("loginPassword","123456");	
        //允许谁可以访问
        //initParameters.put("allow","127.0.0.2");
        //禁止谁访问 禁止ip访问
//        initParameters.put("deny","127.0.0.1");
        bean.setInitParameters(initParameters);
        return bean;
    }

    //filter
    @Bean
    public FilterRegistrationBean webStatFilter() {
        FilterRegistrationBean<Filter> bean = new FilterRegistrationBean<>();
     bean.setFilter(new WebStatFilter());
        HashMap<String, String> initParameters = new HashMap<>();
        //这些东西不进行统计
        initParameters.put("exclusions","*.js,*.css,/druid/*");
        bean.setInitParameters(initParameters);
        bean.setUrlPatterns(Arrays.asList("/*"));
        return bean;
    }
}

配置完成后访问工程路径/druid，通过设置好的账号密码登录后台监控页面

自定义WebMvcConfigurer

@Configuration
public class MyMvcConfig implements WebMvcConfigurer {
    public static class MyViewResolver implements ViewResolver {
        @Override
        public View resolveViewName(String s, Locale locale) throws Exception {
            return null;
        }
    }
    //自定义视图解析器
    @Bean
    public ViewResolver MyViewResolver(){
        return new MyViewResolver();
    }
    //自定义国际化相关
    @Bean
    public LocaleResolver localeResolver() {
        return new MyLocaleResolver();
    }
    //添加拦截器
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new MyInterceptor()).addPathPatterns("/**").excludePathPatterns("/login","/css/**","/img/**");
    }
}

国际化

自定义LocaleResolver类

public class MyLocaleResolver implements LocaleResolver {
    @Override
    public Locale resolveLocale(HttpServletRequest httpServletRequest) {
        String lang = httpServletRequest.getParameter("lang");
        Locale aDefault = Locale.getDefault();
        if(lang!=null && !("".equals(lang))) {
            String[] s = lang.split("_");
            aDefault = new Locale(s[0],s[1]);
        }
        return aDefault;
    }

    @Override
    public void setLocale(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Locale locale) {

    }
}

html层中英文切换传参

<a th:href="@{/login(lang='zh_CN')}">中文</a>
<a th:href="@{/login(lang='en_US')}">英文</a>

添加到自定义的WebMvcConfigurer

@Configuration
public class MyMvcConfig implements WebMvcConfigurer {
    @Bean
    public LocaleResolver localeResolver() {
        return new MyLocaleResolver();
    }
}

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