第三篇：SpringBoot - JdbcTemplates访问Mysql

第一步：在pox.ml添加插件

<!--集成 JdbcTemplate,链接数据库的方式一种-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <!---************************************-->

第二步：在application.properties中添加

## JdbcTemplates
spring.datasource.url=jdbc:mysql://localhost/school  ## 链接的数据库
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.max-idle=10
spring.datasource.max-wait=10000
spring.datasource.min-idle=5
spring.datasource.initial-size=5

第三步：请求数据库

/**
 * @Controller 处理http请求
 * @RestController Spring4 之后新加的注解，原来返回json需要@ResponseBody配合@Controller
 */
@RestController
public class UserController {

    /**
     * @Autowired 将实体对象进行了依赖注入
     */

    @Autowired
    private JdbcTemplate jdbcTemplate;

    @RequestMapping("/getUsers")
    public List<Map<String, Object>> getDbType(){
        String sql = "select * from user"; //user 数据表
        List<Map<String, Object>> list =  jdbcTemplate.queryForList(sql);
        for (Map<String, Object> map : list) {
            Set<Map.Entry<String, Object>> entries = map.entrySet( );
            if(entries != null) {
                Iterator<Map.Entry<String, Object>> iterator = entries.iterator( );
                while(iterator.hasNext( )) {
                    Map.Entry<String, Object> entry =(Map.Entry<String, Object>) iterator.next( );
                    Object key = entry.getKey( );
                    Object value = entry.getValue();
                    System.out.println(key+":"+value);
                }
            }
        }
        return list;
    }
}

访问：http://localhost:8080/getUsers

[{"id":1,"name":"malei","age":"22"}]