Spring的纯注解配置

1.环境搭建

1.1.创建工程

Spring的纯注解配置_第1张图片

1.2.待改造的问题

我们发现,之所以我们现在离不开xml配置文件,是因为我们有一处很关键的配置,如果他要也能用注解配置,那么我们就可以脱离xml文件了:

1.2.1.jdbc配置

<context:property-placeholder location="classpath:db.properties">context:property-placeholder>
    
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" 
          				  destroy-method="close">
        <property name="url" value="${jdbc.url}" />
        <property name="username" value="${jdbc.username}" />
        <property name="password" value="${jdbc.password}" />
        <property name="driverClassName" value="${jdbc.driver}" />
        <property name="maxActive" value="10" />
        <property name="minIdle" value="5" />
    bean>

1.2.2.mybatis配置

    
    <bean id="sessionFactoryBean" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource">property>
        <property name="typeAliasesPackage" value="com.by.pojo">property>
    bean>

    
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.by.mapper">property>
        <property name="sqlSessionFactoryBeanName" value="sessionFactoryBean">property>
    bean>

1.2.3.transactional配置

    <bean id="transactionManager" 
          class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource">property>
    bean>
    
    <tx:annotation-driven transaction-manager="transactionManager"/>

1.2.4.service配置

    
    <context:component-scan base-package="com.by.service">context:component-scan>

1.2.5.springmvc配置


    <context:component-scan base-package="com.by.controller,com.by.exception">context:component-scan>

    
    <mvc:annotation-driven conversion-service="cs">mvc:annotation-driven>

    
    <bean id="cs" class="org.springframework.context.support.ConversionServiceFactoryBean">
        <property name="converters">
            <set>
                <bean class="com.by.converter.MyDateConverter">bean>
            set>
        property>
    bean>

    
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/pages/">property>
        <property name="suffix" value=".jsp">property>
    bean>

    
    <bean id="multipartResolver"
          class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <property name="maxUploadSize" value="5242880" />
        <property name="defaultEncoding" value="UTF-8" />
    bean>
    
    <mvc:resources location="/head/" mapping="/head/**"/>

    
    <mvc:interceptors>
        <mvc:interceptor>
            <mvc:mapping path="/account/**"/>
            <mvc:exclude-mapping path="/account/login">mvc:exclude-mapping>
            <bean class="com.by.interceptor.LoginInterceptor">bean>
        mvc:interceptor>
    mvc:interceptors>

1.2.6.servlet配置


<context-param>
    <param-name>contextConfigLocationparam-name>
    <param-value>classpath:applicationContext-*.xmlparam-value>
context-param>
<listener>
    <listener-class>
        org.springframework.web.context.ContextLoaderListener
    listener-class>
listener>


<servlet>
    <servlet-name>springmvcservlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServletservlet-class>
    <init-param>
        <param-name>contextConfigLocationparam-name>
        <param-value>classpath:springmvc.xmlparam-value>
    init-param>
    <load-on-startup>1load-on-startup>
servlet>
<servlet-mapping>
    <servlet-name>springmvcservlet-name>
    <url-pattern>/url-pattern>
servlet-mapping>

<filter>
    <filter-name>CharacterEncodingFilterfilter-name>
    <filter-class>
        org.springframework.web.filter.CharacterEncodingFilter
    filter-class>
    <init-param>
        <param-name>encodingparam-name>
        <param-value>UTF-8param-value>
    init-param>
filter>
<filter-mapping>
    <filter-name>CharacterEncodingFilterfilter-name>
    <url-pattern>/*url-pattern>
filter-mapping>

2.新注解说明

2.1.@Configuration

  • 作用:

    用于指定当前类是一个spring配置类,可替换xml配置文件,作用和在spring的xml配置文件中的:是一样的。

  • 示例代码

    /**
     * spring的配置类
     */
    @Configuration//等价于,当从一个类上加载到该注解时会创建spring容器
    public class SpringConfiguration{
    }
    

2.2.@ComponentScan

  • 作用:

    用于指定spring在初始化容器时要扫描的包。作用和在spring的xml配置文件中的:

    是一样的。

  • 属性:

    basePackages:用于指定要扫描的包。和该注解中的value属性作用一样。

  • 示例代码

    /**
     * spring的配置类
     */
    @Configuration
    @ComponentScan(basePackages = "com.by")//等价于
    public class SpringConfiguration{
    }
    

2.3.@Bean

  • 作用:

    该注解只能写在方法上,表明使用此方法创建一个对象,并且放入spring容器。作用和在spring的xml配置文件中的:是一样的。

  • 属性:

    name:给当前@Bean注解方法创建的对象指定一个名称(即bean的id)。

  • 示例代码

    public class Dog {
        private String nam;
        private Integer age;
    	//set get......
    }    
    
    @Bean
    public Dog dog(){
        Dog dog = new Dog();
        dog.setNam("二狗");
        dog.setAge(18);
        return dog;
    }
    

2.4.@PropertySource

  • 作用:

    用于加载.properties文件中的配置。作用和在spring的xml配置文件中的:是一样的。

  • 属性:

    value[]:用于指定properties文件位置。如果是在类路径下,需要写上classpath:

  • 示例代码

    #config.properties
    nam=二狗
    age=18
    
    @Configuration
    @PropertySource("classpath:config.properties")
    public class SpringConfiguration {
    
        @Value("${nam}")
        private String nam;
        @Value("${age}")
        private Integer age;
    
        @Bean
        public Dog dog(){
            Dog dog = new Dog();
            dog.setNam(nam);
            dog.setAge(age);
            return dog;
        }
    }
    

2.5.@Import

  • 作用:

    @Import注解是用来导入配置类或者一些需要前置加载的类。作用和在spring的xml配置文件中的:是一样.

  • 属性:

    value[]:用于指定其他配置类的字节码。

  • 示例代码

    @Configuration
    @ComponentScan(basePackages = "com.by")
    @Import({Configuration_Other.class})
    public class SpringConfiguration {
    
    }
    
    @PropertySource("classpath:config.properties")
    public class Configuration_Other {
    
    }
    

3.Spring的纯注解配置

3.1.JdbcConfig

package com.by.config;

import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.PropertySource;

import javax.sql.DataSource;

@PropertySource({"classpath:db.properties"})//
public class DataSourceConfig {

    @Value("${jdbc.driver}")
    private String driver;
    @Value("${jdbc.url}")
    private String url;
    @Value("${jdbc.username}")
    private String userName;
    @Value("${jdbc.password}")
    private String password;

    @Bean //
    public DataSource getDataSource(){
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(driver);
        dataSource.setUrl(url);
        dataSource.setUsername(userName);
        dataSource.setPassword(password);
        return dataSource;
    }
}

3.2.MybatisConfig

package com.by.config;

import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.mapper.MapperScannerConfigurer;
import org.springframework.context.annotation.Bean;

import javax.annotation.Resource;
import javax.sql.DataSource;

public class MyBatisConfig {

    @Bean("sessionFactoryBean")
    public SqlSessionFactoryBean getSqlSessionFactoryBean(DataSource dataSource){
        SqlSessionFactoryBean sessionFactoryBean = new SqlSessionFactoryBean();
        sessionFactoryBean.setDataSource(dataSource);
        return sessionFactoryBean;
    }

    @Bean
    public MapperScannerConfigurer getMapperScannerConfigurer(){
        MapperScannerConfigurer mapperScannerConfigurer = new MapperScannerConfigurer();
        mapperScannerConfigurer.setBasePackage("com.by.mapper");
        mapperScannerConfigurer.setSqlSessionFactoryBeanName("sessionFactoryBean");
        return mapperScannerConfigurer;
    }
}

3.3.TxConfig

package com.by.config;

import org.springframework.context.annotation.Bean;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;

import javax.sql.DataSource;

public class TxManagerConfig {

    @Bean
    public PlatformTransactionManager getPlatformTransactionManager(DataSource dataSource){
        DataSourceTransactionManager transactionManager = new DataSourceTransactionManager();
        transactionManager.setDataSource(dataSource);
        return transactionManager;
    }
}

3.4.SpringConfig

package com.by.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.transaction.annotation.EnableTransactionManagement;
@Configuration
@Import({DataSourceConfig.class, MyBatisConfig.class, TxManagerConfig.class})
@ComponentScan("com.by.service")
@EnableTransactionManagement //等价于
public class ServiceConfig {
}

3.5.SpringMvcConfig

package com.by.config;

import com.by.converter.DateConverter;
import com.by.interceptor.LoginInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.format.FormatterRegistry;
import org.springframework.web.multipart.commons.CommonsMultipartResolver;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

@Configuration
@ComponentScan({"com.by.controller"})
@EnableWebMvc // 
public class SpringmvcConfig implements WebMvcConfigurer {

    @Bean
    public InternalResourceViewResolver getInternalResourceViewResolver(){
        InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
        viewResolver.setPrefix("/WEB-INF/pages/");
        viewResolver.setSuffix(".jsp");
        return viewResolver;
    }

    @Bean("multipartResolver")
    public CommonsMultipartResolver getCommonsMultipartResolver(){
        CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver();
        multipartResolver.setMaxUploadSize(5242880);
        multipartResolver.setDefaultEncoding("UTF-8");
        return multipartResolver;
    }

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new LoginInterceptor()).addPathPatterns("/account/**").excludePathPatterns("/user/**");
    }

    @Override
    public void addFormatters(FormatterRegistry registry) {
        registry.addConverter(new DateConverter());
    }

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/head/**").addResourceLocations("/head/");
    }
}

3.6.WebConfig

package com.by.config;

import org.springframework.web.filter.CharacterEncodingFilter;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

import javax.servlet.Filter;

/**
 * 当类扩展了AbstractAnnotationConfigDispatcherServletlnitializer并将其部署到 Servlet容器时,
 * 容器会自动发现它,并用它来配置Servlet环境
 */
public class WebConfig extends AbstractAnnotationConfigDispatcherServletInitializer {
    
    //加载Spring配置类
    protected Class<?>[] getRootConfigClasses() {
        return new Class[]{ServiceConfig.class};
    }
    
    //加载SpringMVC配置类
    protected Class<?>[] getServletConfigClasses() {
        return new Class[]{SpringmvcConfig.class};
    }
    
    //设置SpringMVC请求地址拦截规则
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }
    
    //设置post请求中文乱码过滤器
    @Override
    protected Filter[] getServletFilters() {
        CharacterEncodingFilter filter = new CharacterEncodingFilter();
        filter.setEncoding("utf-8");
        return new Filter[]{filter};
    }
}

3.7.删除xml配置文件

Spring的纯注解配置_第2张图片

3.8.修改web.xml


<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <welcome-file-list>
        <welcome-file>login.jspwelcome-file>
    welcome-file-list>
web-app>

3.9.测试

略…

总结

--------------------spring的注解--------------------
1、@PropertySource
作用:加载*.properties,等价于context:property-placeholder/
属性:
value:指定*.properties文件的位置
2、@Bean
作用:把实体bean放到ioc容器里,等于
属性:
value:指定IOC容器的key
3、@ComponentScan
作用:指定spring要扫描的包,等价于
属性:
value:指定要扫描的包
4、@Import
作用:导入配置类,等价于
属性:
value:配置类的字节码
5、@Configuration
作用:等价于,spring读取到该注解会创建一个ioc容器

你可能感兴趣的:(spring,java,后端)