Spring Boot 揭秘与实战（二） 数据存储篇 - MySQL

文章链接：http://blog.720ui.com/2016/springboot_02_data_jdbc/

本文讲解 Spring Boot 基础下，如何使用 JDBC，配置数据源和通过 JdbcTemplate 编写数据访问。

环境依赖

修改 POM 文件，添加spring-boot-starter-jdbc依赖。

 <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-jdbc</artifactId>
  </dependency>  

添加mysql依赖。

    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.35</version>
    </dependency>
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>druid</artifactId>
      <version>1.0.14</version>
    </dependency>

数据源

方案一 使用 Spring Boot 默认配置

使用 Spring Boot 默认配置，不需要在创建 dataSource 和 jdbcTemplate 的 Bean。

在 src/main/resources/application.properties 中配置数据源信息。

    spring.datasource.driver-class-name=com.mysql.jdbc.Driver
    spring.datasource.url=jdbc:mysql://localhost:3307/springboot_db
    spring.datasource.username=root
    spring.datasource.password=root

方案二 手动创建

在 src/main/resources/config/source.properties 中配置数据源信息。

    # mysql
    source.driverClassName = com.mysql.jdbc.Driver
    source.url = jdbc:mysql://localhost:3306/springboot_db
    source.username = root
    source.password = root

通过 Java Config 创建 dataSource 和jdbcTemplate。

    @Configuration
    @EnableTransactionManagement
    @PropertySource(value = {"classpath:config/source.properties"})
    public class BeanConfig {

        @Autowired
        private Environment env;

        @Bean(destroyMethod = "close")
        public DataSource dataSource() {
            DruidDataSource dataSource = new DruidDataSource();
            dataSource.setDriverClassName(env.getProperty("source.driverClassName").trim());
            dataSource.setUrl(env.getProperty("source.url").trim());
            dataSource.setUsername(env.getProperty("source.username").trim());
            dataSource.setPassword(env.getProperty("source.password").trim());
            return dataSource;
        }

        @Bean
        public JdbcTemplate jdbcTemplate() {
            JdbcTemplate jdbcTemplate = new JdbcTemplate();
            jdbcTemplate.setDataSource(dataSource());
            return jdbcTemplate;
        }
    }

SQL语句初始化

先初始化需要用到的SQL脚本。

    CREATE DATABASE /*!32312 IF NOT EXISTS*/`springboot_db` /*!40100 DEFAULT CHARACTER SET utf8 */;

    USE `springboot_db`;

    DROP TABLE IF EXISTS `t_author`;

    CREATE TABLE `t_author` (
      `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT COMMENT '用户ID',
      `real_name` varchar(32) NOT NULL COMMENT '用户名称',
      `nick_name` varchar(32) NOT NULL COMMENT '用户匿名',
      PRIMARY KEY (`id`)
    ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

使用JdbcTemplate操作

实体对象

    public class Author {
        private Long id;
        private String realName;
        private String nickName;
        // SET和GET方法
    }

DAO相关

public interface AuthorDao {
        int add(Author author);
        int update(Author author);
        int delete(Long id);
        Author findAuthor(Long id);
        List<Author> findAuthorList();
    }

我们来定义实现类，通过JdbcTemplate定义的数据访问操作。

 @Repository
    public class AuthorDaoImpl implements AuthorDao {

        @Autowired
        private JdbcTemplate jdbcTemplate;

        @Override
        public int add(Author author) {
            return jdbcTemplate.update("insert into t_author(real_name, nick_name) values(?, ?)", 
                    author.getRealName(), author.getNickName());
        }

        @Override
        public int update(Author author) {
            return jdbcTemplate.update("update t_author set real_name = ?, nick_name = ? where id = ?", 
                    new Object[]{author.getRealName(), author.getNickName(), author.getId()});      
        }

        @Override
        public int delete(Long id) {
            return jdbcTemplate.update("delete from t_author where id = ?", id);
        }

        @Override
        public Author findAuthor(Long id) {
            List<Author> list = jdbcTemplate.query("select * from t_author where id = ?", new Object[]{id}, new BeanPropertyRowMapper(Author.class));
            if(null != list && list.size()>0){
                Author auhtor = list.get(0);
                return auhtor;
            }else{
                return null;
            }
        }
        @Override
        public List<Author> findAuthorList() {
            List<Author> list = jdbcTemplate.query("select * from t_author", new Object[]{}, new BeanPropertyRowMapper<Author>(Author.class));
            return list;
        }
    }

Service相关

public interface AuthorService {
        int add(Author author);
        int update(Author author);
        int delete(Long id);
        Author findAuthor(Long id);
        List<Author> findAuthorList();
    }

我们来定义实现类，Service层调用Dao层的方法，这个是典型的套路。

 @Service("authorService")
    public class AuthorServiceImpl implements AuthorService {
        @Autowired
        private AuthorDao authorDao;

        @Override
        public int add(Author author) {
            return this.authorDao.add(author);
        }

        @Override
        public int update(Author author) {
            return this.authorDao.update(author);      
        }

        @Override
        public int delete(Long id) {
            return this.authorDao.delete(id);
        }

        @Override
        public Author findAuthor(Long id) {
            return this.authorDao.findAuthor(id);
        }

        @Override
        public List<Author> findAuthorList() {
            return this.authorDao.findAuthorList();
        }
    }

Controller相关

为了展现效果，我们先定义一组简单的　RESTful API 接口进行测试。

 @RestController
    @RequestMapping(value="/data/jdbc/author")
    public class AuthorController {
      @Autowired
      private AuthorService authorService;
      /**
       * 查询用户列表
       */
      @RequestMapping(method = RequestMethod.GET)
      public Map<String,Object> getAuthorList(HttpServletRequest request) {        
        List<Author> authorList = this.authorService.findAuthorList();
        Map<String,Object> param = new HashMap<String,Object>();
        param.put("total", authorList.size());
        param.put("rows", authorList);
        return param;
      }
      /**
       * 查询用户信息
       */
      @RequestMapping(value = "/{userId:\\d+}", method = RequestMethod.GET)
      public Author getAuthor(@PathVariable Long userId, HttpServletRequest request) {
        Author author = this.authorService.findAuthor(userId);
        if(author == null){
            throw new RuntimeException("查询错误");
        }
        return author;
      }

      /**
       * 新增方法
       */
      @RequestMapping(method = RequestMethod.POST)
      public void add(@RequestBody JSONObject jsonObject) {
        String userId = jsonObject.getString("user_id");
        String realName = jsonObject.getString("real_name");
        String nickName = jsonObject.getString("nick_name");
        Author author = new Author();
        if (author!=null) {
            author.setId(Long.valueOf(userId));
        }
        author.setRealName(realName);
        author.setNickName(nickName);
        try{
            this.authorService.add(author);
        }catch(Exception e){
            e.printStackTrace();
            throw new RuntimeException("新增错误");
        }
      }
      /**
       * 更新方法
       */
      @RequestMapping(value = "/{userId:\\d+}", method = RequestMethod.PUT)
        public void update(@PathVariable Long userId, @RequestBody JSONObject jsonObject) {
        Author author = this.authorService.findAuthor(userId);
        String realName = jsonObject.getString("real_name");
        String nickName = jsonObject.getString("nick_name");
        author.setRealName(realName);
        author.setNickName(nickName);
        try{
            this.authorService.update(author);
        }catch(Exception e){
            e.printStackTrace();
            throw new RuntimeException("更新错误");
        } 
      }
      /**
       * 删除方法
       */
      @RequestMapping(value = "/{userId:\\d+}", method = RequestMethod.DELETE)
        public void delete(@PathVariable Long userId) {
        try{
            this.authorService.delete(userId);
        }catch(Exception e){
            throw new RuntimeException("删除错误");
        }
      }
    }

总结

通过，上面这个简单的案例，我们发现 Spring Boot 仍然秉承了 Spring 框架的一贯套路，并简化 Spring 应用的初始搭建以及开发过程。

源代码

相关示例完整代码： [springboot-action](https://github.com/lianggzone/springboot-action)

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