Spring MVC 完全注解方式配置web项目

在 servlet 3.0 开始web项目可以完全不需要web.xml配置文件了，所以本文的配置只在支持servlet 3.0及以上的web容器中有效

　　使用的是spring mvc (4.3.2.RELEASE) + thymeleaf(3.0.2.RELEASE), 持久层使用的 spring的 JdbcTemplate， PS：推荐一个很好用的对JdbcTemplate封装的框架：https://github.com/selfly/dexcoder-assistant 。 下面开始具体的配置：

配置spring mvc DispatcherServlet

DispatcherServlet 是spring mvc的核心， Spring 提供了一个快速配置DispatcherServlet的类 AbstractAnnotationConfigDispatcherServletInitializer，具体代码如下：

其中 onStartup() 是 WebApplicationInitializer 接口中的方法，用户配置其他的 filter 和 listener

getRootConfigClasses() 获取配置类，我理解的相当于 applicationContext.xml 创建的上下文

getServletConfigClasses()获取配置类，相当于 mvc-servlet.xml 创建的上下文

此类上不需要任何注解，

package com.liulu.bank.config;

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

import javax.servlet.FilterRegistration;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import java.nio.charset.StandardCharsets;

/**
 * User : liulu
 * Date : 2016-10-7 15:12
 */
public class WebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer implements WebApplicationInitializer {

    @Override
    protected Class>[] getRootConfigClasses() {
        return new Class>[]{RootConfig.class};
    }

    @Override
    protected Class>[] getServletConfigClasses() {
        return new Class>[]{WebConfig.class};
    }

    /**
     * 配置DispatcherServlet 匹配的路径
     * @return
     */
    @Override
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }

    /**
     * 配置其他的 servlet 和 filter
     *
     * @param servletContext
     * @throws ServletException
     */
    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        FilterRegistration.Dynamic encodingFilter = servletContext.addFilter("encodingFilter", CharacterEncodingFilter.class);
        encodingFilter.setInitParameter("encoding", String.valueOf(StandardCharsets.UTF_8));
        encodingFilter.setInitParameter("forceEncoding", "true");
        encodingFilter.addMappingForUrlPatterns(null, false, "/*");
    }
}

配置 applicationContext.xml，由RootConfig类实现

package com.liulu.bank.config;

import com.mchange.v2.c3p0.ComboPooledDataSource;
import org.springframework.context.annotation.*;
import org.springframework.core.env.Environment;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.stereotype.Controller;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;

import javax.annotation.Resource;
import javax.sql.DataSource;
import java.beans.PropertyVetoException;

/**
 * User : liulu
 * Date : 2016-10-7 15:36
 */
@Configuration
@PropertySource("classpath:config.properties") // 导入属性文件
@EnableAspectJAutoProxy // 相当于 xml 中的 
@EnableTransactionManagement // 开启注解事务
@ComponentScan(basePackages = {"com.liulu.lit", "com.liulu.bank"}, excludeFilters = @ComponentScan.Filter(classes = Controller.class  ))
public class RootConfig {

    // 上面导入的属性文件中的属性会 注入到 Environment 中
    @Resource
    private Environment env;

    /**
     * 配置数据库连接池 c3p0，
     * @return
     * @throws PropertyVetoException
     */
    @Bean
    public DataSource dataSource() throws PropertyVetoException {
        ComboPooledDataSource dataSource = new ComboPooledDataSource();
        dataSource.setJdbcUrl(env.getProperty("db.url"));
        dataSource.setDriverClass(env.getProperty("db.driver"));
        dataSource.setUser(env.getProperty("db.user"));
        dataSource.setPassword(env.getProperty("db.password"));
        dataSource.setMinPoolSize(Integer.valueOf(env.getProperty("pool.minPoolSize")));
        dataSource.setMaxPoolSize(Integer.valueOf(env.getProperty("pool.maxPoolSize")));
        dataSource.setAutoCommitOnClose(false);
        dataSource.setCheckoutTimeout(Integer.valueOf(env.getProperty("pool.checkoutTimeout")));
        dataSource.setAcquireRetryAttempts(2);
        return dataSource;
    }

    /**
     * 配置事物管理器
     * @param dataSource
     * @return
     */
    @Bean
    public PlatformTransactionManager transactionManager(DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean
    public JdbcTemplate jdbcTemplate (DataSource dataSource) {
        return new JdbcTemplate(dataSource);
    }


}

config.properties 文件在 resources 目

#数据库配置
db.url=jdbc:mysql://192.168.182.135:3306/bank
db.driver=com.mysql.jdbc.Driver
db.user=root
db.password=123456

#数据库连接池配置
#连接池中保留的最小连接数
pool.minPoolSize=5
#连接池中保留的最大连接数
pool.maxPoolSize=30
#获取连接超时时间
pool.checkoutTimeout=1000

配置 servlet.xml, 由WebConfig类实现

Thymeleaf 模板配置也在下面

package com.liulu.bank.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.stereotype.Controller;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.thymeleaf.TemplateEngine;
import org.thymeleaf.spring4.SpringTemplateEngine;
import org.thymeleaf.spring4.templateresolver.SpringResourceTemplateResolver;
import org.thymeleaf.spring4.view.ThymeleafViewResolver;
import org.thymeleaf.templatemode.TemplateMode;

import java.nio.charset.StandardCharsets;

/**
 * User : liulu
 * Date : 2016-10-7 15:16
 */
@Configuration
@EnableWebMvc // 启用 SpringMVC ，相当于 xml中的 
@ComponentScan(basePackages = {"com.liulu.bank.controller", "com.liulu.lit"},
        includeFilters = @ComponentScan.Filter(classes = Controller.class),
        useDefaultFilters = false)
public class WebConfig extends WebMvcConfigurerAdapter {

    /**
     * 设置由 web容器处理静态资源 ，相当于 xml中的
     */
    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }

    /**
     * 下面三个bean 配置 Thymeleaf 模板
     * @return
     */
    @Bean
    public SpringResourceTemplateResolver templateResolver() {
        SpringResourceTemplateResolver templateResolver = new SpringResourceTemplateResolver();
        templateResolver.setPrefix("/WEB-INF/templates/");
        templateResolver.setSuffix(".html");
        templateResolver.setTemplateMode(TemplateMode.HTML);
        templateResolver.setCharacterEncoding(String.valueOf(StandardCharsets.UTF_8));
        return templateResolver;
    }

    @Bean
    public TemplateEngine templateEngine(SpringResourceTemplateResolver templateResolver) {
        SpringTemplateEngine templateEngine = new SpringTemplateEngine();
        templateEngine.setTemplateResolver(templateResolver);
        return templateEngine;
    }

    @Bean
    public ViewResolver viewResolver(TemplateEngine templateEngine) {
        ThymeleafViewResolver viewResolver = new ThymeleafViewResolver();
        viewResolver.setTemplateEngine(templateEngine);
        viewResolver.setCharacterEncoding(String.valueOf(StandardCharsets.UTF_8));
        return viewResolver;
    }

}