[Java知识库]【Java从零到架构师第③季】【38】分模块构建SSM项目

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守破离

module—parent

pom.xml：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>programmer.lp.ssmdividing</groupId>
    <artifactId>SSM_dividing_module</artifactId>
    <version>1.0.0</version>

    <!-- 作为父项目，packaging必须是pom -->
    <packaging>pom</packaging>

    <!-- 聚合：统一管理这些被聚合的项目 -->
    <modules>
        <module>dao</module>
        <module>service</module>
        <module>web</module>
    </modules>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
</project>

module—dao

dao层是数据访问层，是MyBatis干活的地方。

pom.xml：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <artifactId>SSM_dividing_module</artifactId>
        <groupId>programmer.lp.ssmdividing</groupId>
        <version>1.0.0</version>
    </parent>

    <artifactId>dao</artifactId>

    <dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.49</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.2.8</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.7</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.13.0</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.2.8.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>2.0.6</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.2.8.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.2.7</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13.2</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

db.properties：

jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/test_mybatis?useSSL=false
jdbc.username=root
jdbc.password=root

mybatis.typeAliasesPackage=programmer.lp.domain
mybatis.mapperScanPackage=programmer.lp.dao
mybatis.configLocation=mybatis-config.xml

mybatis-config.xml：

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <settings>
        <setting name="mapUnderscoreToCamelCase" value="true"/>
    </settings>
</configuration>

Converter：

public class DateConverter implements Converter<String, Date> {
    private Set<String> formats;
    public void setFormats(Set<String> formats) {
        this.formats = formats;
    }
    @Override
    public Date convert(String dateStr) {
        if (null == formats || formats.isEmpty()) return null;
        for (String format : formats) {
            try {
                return new SimpleDateFormat(format).parse(dateStr);
            } catch (Exception e) {
                System.out.println("不支持：<" + format + ">格式！");
            }
        }
        return null;
    }
}

Dao：

public interface SkillDao {
    @Insert("INSERT INTO skill(name, level) VALUES(#{name}, #{level})")
    @SelectKey(statement = "SELECT LAST_INSERT_ID()",
            keyProperty = "id",
            keyColumn = "id",
            before = false,
            resultType = Integer.class)
    boolean insert(Skill skill);

    @Delete(("DELETE FROM skill WHERE id = #{id}"))
    boolean delete(Integer id);

    @Update("UPDATE skill SET name = #{name}, level = #{level} WHERE id = #{id}")
    boolean update(Skill skill);

    @Select("SELECT id, created_time, name, level FROM skill WHERE id = #{id}")
    Skill get(Integer id);

    @Select("SELECT id, created_time, name, level FROM skill")
    List<Skill> list();
}

DaoConfiguration：

@PropertySource("classpath:db.properties")
@MapperScan("${mybatis.mapperScanPackage}")
public class DaoConfiguration {
    @Value("${jdbc.driverClassName}")
    private String driverClassName;
    @Value("${jdbc.url}")
    private String url;
    @Value("${jdbc.username}")
    private String username;
    @Value("${jdbc.password}")
    private String password;

    @Value("${mybatis.typeAliasesPackage}")
    private String typeAliasesPackage;
    @Value("${mybatis.configLocation}")
    private String configLocation;

    @Bean
    public DataSource dataSource() {
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(driverClassName);
        dataSource.setUrl(url);
        dataSource.setUsername(username);
        dataSource.setPassword(password);
        return dataSource;
    }

    @Bean
    public SqlSessionFactoryBean sqlSessionFactory(DataSource dataSource) {
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dataSource);
        sqlSessionFactoryBean.setTypeAliasesPackage(typeAliasesPackage);
        Resource location = new ClassPathResource(configLocation);
        sqlSessionFactoryBean.setConfigLocation(location);
        return sqlSessionFactoryBean;
    }

    @Bean
    public DateConverter dateConverter() {
        DateConverter dateConverter = new DateConverter();
        Set<String> set = new LinkedHashSet<>();
        set.add("yyyy-MM-dd");
        set.add("yyyy/MM/dd");
        set.add("yyyy年MM月dd日");
        dateConverter.setFormats(set);
        return dateConverter;
    }
}

module—service

service层是业务层，一般需要Spring的事务管理。

pom.xml：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <artifactId>SSM_dividing_module</artifactId>
        <groupId>programmer.lp.ssmdividing</groupId>
        <version>1.0.0</version>
    </parent>

    <artifactId>service</artifactId>

    <dependencies>
        <dependency>
            <groupId>programmer.lp.ssmdividing</groupId>
            <artifactId>dao</artifactId>
            <version>1.0.0</version>
        </dependency>
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.6</version>
        </dependency>
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjrt</artifactId>
            <version>1.9.6</version>
        </dependency>
    </dependencies>

</project>

ServiceConfiguration：

@EnableTransactionManagement
@ComponentScan("programmer.lp.service")
public class ServiceConfiguration {

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

}

SkillService：

@Service
@Transactional
public class SkillServiceImpl implements SkillService {
    @Autowired
    private SkillDao dao;

    @Override
    public boolean remove(Integer id) {
        return dao.delete(id);
    }

    @Override
    public boolean save(Skill skill) {
        final Integer skillId = skill.getId();
        if (skillId == null || skillId < 1) {
            boolean result = dao.insert(skill);
            System.out.println(skill.getId());
            return result;
        }
        return dao.update(skill);
    }

    @Transactional(propagation = Propagation.SUPPORTS)
    @Override
    public Skill get(Integer id) {
        return dao.get(id);
    }

    @Transactional(readOnly = true)
    @Override
    public List<Skill> list() {
        return dao.list();
    }
}

module—web

web层就是controller层（相当于servlet），是SpringMVC干活的地方。

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <artifactId>SSM_dividing_module</artifactId>
        <groupId>programmer.lp.ssmdividing</groupId>
        <version>1.0.0</version>
    </parent>

    <artifactId>web</artifactId>

    <packaging>war</packaging>

    <dependencies>
        <dependency>
            <groupId>programmer.lp.ssmdividing</groupId>
            <artifactId>service</artifactId>
            <version>1.0.0</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.2.8.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>javax.servlet.jsp-api</artifactId>
            <version>2.3.3</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>4.0.1</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>jstl</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>
        <dependency>
            <groupId>taglibs</groupId>
            <artifactId>standard</artifactId>
            <version>1.1.2</version>
        </dependency>
        <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
            <version>1.4</version>
        </dependency>
    </dependencies>
</project>

WebConfiguration：

@EnableWebMvc
@ComponentScan("programmer.lp.controller")
public class WebConfiguration implements WebMvcConfigurer {
    @Autowired
    private DateConverter dateConverter;

    @Override
    public void addFormatters(FormatterRegistry registry) {
        registry.addConverter(dateConverter);
    }
    
    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }

    @Override
    public void configurePathMatch(PathMatchConfigurer configurer) {
        configurer.setUseSuffixPatternMatch(false);
    }

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

    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        StringHttpMessageConverter stringConverter = new StringHttpMessageConverter();
        stringConverter.setDefaultCharset(StandardCharsets.UTF_8);
        MappingJackson2HttpMessageConverter jacksonConverter = new MappingJackson2HttpMessageConverter();
        jacksonConverter.setDefaultCharset(StandardCharsets.UTF_8);
        converters.add(stringConverter);
        converters.add(jacksonConverter);
    }
}

Controller：

/**
 规定：
 读：使用GET请求
 写：使用POST请求
 */

@Controller
@RequestMapping("/skill")
public class SkillController {
    @Autowired
    private SkillService service;

    @PostMapping("/remove")
    @ResponseBody
    public String remove(Integer id) {
        return service.remove(id) ? "删除成功" : "删除失败";
    }

    @PostMapping("/save")
    @ResponseBody
    public String save(Skill skill) {
        return service.save(skill) ? "保存成功" : "保存失败";
    }

    @GetMapping("/get")
    @ResponseBody
    public Skill get(Integer id) {
        return service.get(id);
    }

    @GetMapping("/list")
    @ResponseBody
    public List<Skill> list() {
        return service.list();
    }
}

Initializer：

public class ApplicationInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
    /**
     * 父容器的配置类
     */
    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class[]{DaoConfiguration.class, ServiceConfiguration.class};
    }

    /**
     * 子容器的配置类(SpringMVC的配置类)
     */
    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class[]{WebConfiguration.class};
    }

    /**
     * 配置DispatcherServlet的 url-pattern
     */
    @Override
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }

    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        super.onStartup(servletContext);
        FilterRegistration.Dynamic encodingFilter =
                servletContext.addFilter("CharacterEncodingFilter", CharacterEncodingFilter.class);
        encodingFilter.setInitParameter("encoding", "UTF-8");
        encodingFilter.addMappingForUrlPatterns(null, false, "/*");
    }
}

参考

小码哥-李明杰: Java从0到架构师③进阶互联网架构师.

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