在春季类中定义 bean 的更好方法

Question

在 spring 4 应用程序中，我创建了两个 bean，如下所示：

    <!-- schemaFactory-->
    <bean id="schemaFact" class="javax.xml.validation.SchemaFactory"
        factory-method="newInstance">
        <constructor-arg value="http://www.w3.org/2001/XMLSchema" />
    </bean>

  <!-- schema -->
    <bean id="schema" class="javax.xml.validation.Schema"
        factory-bean="schemaFact" factory-method="newSchema">
        <constructor-arg value="classpath:/configs/sample.xsd" />
    </bean>

一个生成模式工厂，另一个使用工厂（针对 xsd 验证 xml）。

在代码中：

public class example {

    @Inject
    private Schema aschema;
    ......

   private validate(){
       Validator validator = aschema.newValidator();
       validator.validate(xmlFile); 
 }

}

这很好用，但我想知道是否可以以我们不需要单独定义工厂 bean 的方式编写这个 spring.xml（并且最后有一个更简单的 spring.xml）。如您所见，我只需要将schema bean 注入到我的example 类中，而schemaFact 则根本不需要。

Answer 1

无论您是否直接使用它们，注入良好的依赖项都必须对 spring bean 进行。

因此，即使您没有直接在代码中使用SchemaFactory，而是将其作为依赖项注入另一个 Spring bean，两者都必须是 Spring 托管 bean

你可以考虑使用注解然后你根本不需要spring文件。

Answer 2

这是一些在 java 类中创建 bean 的示例代码。可以在这里创建任何 bean 并在相关类中自动连接。

这个注释给了我们很大的支持ex- @Configuration

import java.util.Properties;
import javax.persistence.SharedCacheMode;

import........

@Configuration
@ComponentScan(basePackages = {"<package>"})
@EnableTransactionManagement
@PropertySources(value = {@PropertySource(value = {"<property file path>"})})
public class ModulesConfig {

    private static final Logger log = LoggerFactory.getLogger(ModulesConfig.class);

    @Autowired
    private Environment environment;

    @Bean(destroyMethod = "close")
    public BoneCPDataSource getDataSource() {
        BoneCPDataSource dataSource = new BoneCPDataSource();
        dataSource.setDriverClass(environment.getProperty("database.driver"));
        dataSource.setJdbcUrl(environment.getProperty("database.url"));
        dataSource.setUsername(environment.getProperty("database.username"));
        dataSource.setPassword(environment.getProperty("database.password"));
        dataSource.setIdleConnectionTestPeriodInMinutes(30);
        dataSource.setMaxConnectionsPerPartition(5);
        dataSource.setMinConnectionsPerPartition(2);
        dataSource.setPartitionCount(3);
        dataSource.setAcquireIncrement(2);
        dataSource.setStatementsCacheSize(100);

        return dataSource;
    }

    @Bean
    @Primary
    public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
        JpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();

        Properties jpaProperties = new Properties();
        jpaProperties.setProperty("hibernate.dialect", "org.hibernate.dialect.MySQL5Dialect");
        jpaProperties.setProperty("hibernate.showSql", "false");

        LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
        em.setDataSource(getDataSource());
        em.setPersistenceUnitName("entityManagerFactory");
        em.setPackagesToScan("<packages>");
        em.setJpaVendorAdapter(vendorAdapter);
        em.setJpaProperties(jpaProperties);
        em.setSharedCacheMode(SharedCacheMode.ENABLE_SELECTIVE);

        return em;
    }

    @Bean(name = "transactionManager1")
    @Primary
    public JpaTransactionManager getTransactionManager() {
        JpaTransactionManager transactionManager = new JpaTransactionManager();
        transactionManager.setEntityManagerFactory(entityManagerFactory().getObject());

        return transactionManager;
    }

    @Bean(name = "transactionManager2")
    public JpaTransactionManager getTransactionManager2() {
        JpaTransactionManager transactionManager = new JpaTransactionManager();
        transactionManager.setEntityManagerFactory(entityManagerFactory2().getObject());

        return transactionManager;
    }

    @Bean
    @Qualifier("VoucherServiceMarshaller")
    public Jaxb2Marshaller getVoucherServiceMarshaller() {
        Jaxb2Marshaller marshaller = new Jaxb2Marshaller();
        marshaller.setContextPath(environment.getProperty("voucher.service.marshaller.contextPath"));

        return marshaller;
    }

    @Bean
    @Qualifier("VoucherServiceTemplate")
    public WebServiceTemplate getVoucherServiceTemplate() {
        WebServiceTemplate template = new WebServiceTemplate(getVoucherServiceMarshaller());
        template.setDefaultUri(environment.getProperty("voucher.service.defaultUri"));

        return template;
    }

    @Bean
    public VoucherServiceProxy getVoucherServiceProxy() {
        VoucherServiceProxy voucherServiceProxy = new VoucherServiceProxy();

        return voucherServiceProxy;
    }

    @Bean
    public MessageSource messageSource() {
        ReloadableResourceBundleMessageSource messageSource = new ReloadableResourceBundleMessageSource();
        messageSource.setBasename("classpath:messages");
        messageSource.setDefaultEncoding("UTF-8");

        return messageSource;
    }

    @Bean
        public JavaMailSender javaMailSender() {
            JavaMailSenderImpl mailSender = new JavaMailSenderImpl();
            Properties mailProperties = new Properties();

            mailProperties.put("mail.smtp.host", environment.getProperty("mail.smtp.host"));
            mailProperties.put("mail.smtp.socketFactory.port", environment.getProperty("mail.smtp.socketFactory.port"));
            mailProperties.put("mail.smtp.socketFactory.class", environment.getProperty("mail.smtp.socketFactory.class"));
            mailProperties.put("mail.smtp.auth", environment.getProperty("mail.smtp.auth"));

            mailSender.setJavaMailProperties(mailProperties);

            mailSender.setUsername(environment.getProperty("mail.username"));
            mailSender.setPassword(environment.getProperty("mail.password"));

            return mailSender;
        }


    @Bean
    public ChargingGatewayServiceProxy getChargingGatewayServiceProxy() {
        ChargingGatewayServiceProxy chargingGatewayServiceProxy = new ChargingGatewayServiceProxy();

        return chargingGatewayServiceProxy;
    }

    @Bean
    @Qualifier("ChargingGatewayServiceMarshaller")
    public Jaxb2Marshaller getChargingGatewayServiceMarshaller() {
        Jaxb2Marshaller marshaller = new Jaxb2Marshaller();
        marshaller.setContextPath(environment.getProperty("cg.service.marshaller.contextPath1"));

        return marshaller;
    }

    @Bean
    @Qualifier("ChargingGatewayServiceTemplate")
    public WebServiceTemplate getChargingGatewayServiceTemplate() {
        WebServiceTemplate template = new WebServiceTemplate(getChargingGatewayServiceMarshaller());
        template.setDefaultUri(environment.getProperty("cg.service.url"));
        template.setMessageSender(getMessageSender());

        return template;
    }

    @Bean
    public HttpComponentsMessageSender getMessageSender() {
        HttpComponentsMessageSender httpComponentsMessageSender = new HttpComponentsMessageSender();
        httpComponentsMessageSender.setConnectionTimeout(Integer.parseInt(environment.getProperty("cg.connection.timeout")));
        httpComponentsMessageSender.setReadTimeout(Integer.parseInt(environment.getProperty("cg.read.timeout")));

        return  httpComponentsMessageSender;
    }

    @Bean
    public RestTemplate restTemplate() {
        return new RestTemplate(clientHttpRequestFactory());
    }

    private ClientHttpRequestFactory clientHttpRequestFactory() {
        HttpComponentsClientHttpRequestFactory factory = new HttpComponentsClientHttpRequestFactory();
        factory.setReadTimeout(50000);
        factory.setConnectTimeout(50000);
        return factory;
    }

    @Bean
    public Cache cacheTemp() {
        net.sf.ehcache.CacheManager cm = net.sf.ehcache.CacheManager.create().getInstance();

        cm.addCache("cacheTemp");
        Cache cache = cm.getCache("cacheTemp");

        return cache;
    }

    @Bean
    public Cache cacheActive() {
        net.sf.ehcache.CacheManager cm = net.sf.ehcache.CacheManager.create().getInstance();

        cm.addCache("cacheActive");
        Cache cache = cm.getCache("cacheActive");

        return cache;
    }

    @Bean
    public Cache cache() {
        net.sf.ehcache.CacheManager cm = net.sf.ehcache.CacheManager.create().getInstance();

        cm.addCache("cache");
        Cache cache = cm.getCache("cache");

        return cache;
    }

}