一、项目分层

二、连接数据库

步骤一、引入连接数据库的相关依赖

       
     
      org.springframework.boot
        
     
      spring-boot-starter-jdbc
     
    
    
       
     
      com.alibaba
        
     
      druid
        
     
      1.1.14
     
    
    
       
     
      mysql
        
     
      mysql-connector-java
        
     
      8.0.15
     
    
    
       
     
      org.projectlombok
        
     
      lombok
        
     
      1.18.6
        
     
      provided
     
    

步骤二、配置数据库连接池相关信息

步骤三、初始化数据库连接

@Configuration@PropertySource(value = "classpath:application.properties")public class DataSourceConfiguration {    @Bean(destroyMethod = "close", initMethod = "init")    @ConfigurationProperties(prefix = "spring.datasource")    public DataSource druidDataSource() {        DruidDataSource druidDataSource = new DruidDataSource();        return druidDataSource;    }}

启动报错：

Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.

解决方法：

步骤四、增删改查

1、新增

/** * 新增用户 * @param user 用户信息 * @return */@Overridepublic int add(User user) {    String sql = "insert into sys_user (user_name,password,email,telephone) values(?,?,?,?)";    int result = jdbcTemplate.update(sql, user.getUserName(),user.getPassword(),user.getEmail(),user.getTelephone());    return result;}

2、修改

/** * 修改用户 用户信息 * @param user * @return */@Overridepublic int update(User user) {    String sql = "update sys_user set user_name =?,password=?,email=?,telephone=? where id = ?";    int result = jdbcTemplate.update(sql, user.getUserName(),user.getPassword(),user.getEmail(),user.getTelephone(),user.getId());    return result;}

3、删除

/** * 删除用户 * @param id 用户id * @return */@Overridepublic int deleteById(String id) {    String sql = "delete from sys_user where id = ?";    int result = jdbcTemplate.update(sql, id);    return result;}

4、根据用户id获取用户

/** * 根据用户id获取用户 * @param id 用户id * @return */@Overridepublic User getUserById(String id) {    String sql="select * from sys_user where id=?";    return jdbcTemplate.queryForObject(sql, new RowMapper
    
     () {        @Override        public User mapRow(ResultSet rs, int rowNum) throws SQLException {            return User.builder()                    .id(rs.getInt(1))                    .userName(rs.getString(2))                    .password(rs.getString(3))                    .email(rs.getString(4))                    .telephone(rs.getString(5))                    .build();        }    }, id);}
    

注意： 1、接收参数的两种方式 （1）参数在路径上

（2）问号传参