Springboot-JDBC

• 配置文件

#serverTimezone=GMT：设置时区
spring:
  datasource:
    username: root
    password: 123456
    url: jdbc:mysql://localhost:3306/数据库名?serverTimezone=GMT
    driver-class-name: com.mysql.cj.jdbc.Driver

• 数据库使用，增删改查，Controller

@RestController
public class JDBCController {

    @Autowired
    JdbcTemplate jdbcTemplate;

    //查询数据库的所有信息
    //没有实体类，数据库中的东西，怎么获取？
    @GetMapping("/userList")
    public List<Map<String,Object>> userList(){
        String sql = "select * from springboot_mybatis.user";
        List<Map<String, Object>> list_maps = jdbcTemplate.queryForList(sql);
        return list_maps;
    }

    @GetMapping("/addUser")
    public String addUser(){
        String sql = "insert into springboot_mybatis.user(id,userName,passWord,realName) values (3,‘DJ‘,‘123456‘,‘DingJie‘)";
        jdbcTemplate.update(sql);
        return "Update_OK";
    }

    @GetMapping("/updateUser/{id}")
    public String updateUser(@PathVariable("id")Integer id){
        String sql = "update springboot_mybatis.user set userName=?,passWord=? where id = "+id;

        //数据封装
        Object[] objects = new Object[2];
        objects[0] = "小明";
        objects[1] = "11111";
        jdbcTemplate.update(sql,objects);
        return "Update_OK";
    }

    @GetMapping("/deleteUser/{id}")
    public String deleteUser(@PathVariable("id")Integer id){
        String sql = "delete from springboot_mybatis.user where id = ?";

        jdbcTemplate.update(sql,id);
        return "Delete_OK";
    }
}

注意：

springboot 2.3.7版本使用IDEA创建项目时，勾选了有关数据库的选项

springboot会自动在生成的properties文件中添加配置模板的信息：

# 应用名称
spring.application.name=springboot-04-data
# 数据库驱动：
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
# 数据源名称
spring.datasource.name=defaultDataSource
# 数据库连接地址
spring.datasource.url=jdbc:mysql://localhost:3306/blue?serverTimezone=UTC
# 数据库用户名&密码：
spring.datasource.username=***
spring.datasource.password=***
# 应用服务 WEB 访问端口
server.port=8080

如果使用yaml文件进行配置，会导致数据库连接的失败，建议使用yaml，干掉properties。

02. Springboot-druid数据源

• druid数据源依赖

<!--Druid-->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.2.6</version>
</dependency>

• log4j依赖

<!--log4j-->
<dependency>
    <groupId>log4j</groupId>
    <artifactId>log4j</artifactId>
    <version>1.2.12</version>
</dependency>

• druid数据元配置文件

spring:
  datasource:
    username: root
    password: 123456
#    url: jdbc:mysql://localhost:3306/springboot_mybatis?serverTimezone=GMT&useUnicode=true&characterEncoding=utf8&useSSL=false
#    失去问题
    url: jdbc:mysql://localhost:3306/springboot_mybatis?serverTimezone=GMT
    driver-class-name: com.mysql.cj.jdbc.Driver
    type: com.alibaba.druid.pool.DruidDataSource

    #springboot 默认是不注入这些属性值的，需要自己绑定
    #druid 数据源专有配置
    initialSize: 5
    minIdle: 5
    maxActive: 20
    maxWait: 60000
    timeBetweenEvictionRunsMillis: 60000
    minEvictableIdleTimeMillis: 300000
    validationQuery: SELECT 1 FROM DUAL
    testWhileIdle: true
    testOnBorrow: false
    testOnReturn: false
    poolPreparedStatements: true

    #配置监控统计拦截器filters，stat：监控统计、log4j：日志记录、wall:防御sql注入
    #如果允许时报错  java.lang.ClassNotFoundException: org.apache.log4j.Priority
    #则导入log4j依赖即可，Maven
    filters: stat,wall,log4j
    maxPoolPreparedStatementPerConnectionSize: 20
    userGlobalDataSourceStat: true
    connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500

• druid的使用
  新建DruidConfig
  

@Configuration
public class DruidConfig {

    @Bean
    @ConfigurationProperties(prefix = "spring.datasource")
    public DataSource druidDataSource(){
        return new DruidDataSource();
    }

    //后台监控：web.xml
    @Bean
    public ServletRegistrationBean statViewServlet(){
        ServletRegistrationBean<StatViewServlet> registrationBean = new ServletRegistrationBean<>(new StatViewServlet(), "/druid/*");

        //后台需要有人登录，账号密码配置
        HashMap<String, String> initParameters = new HashMap<>();
        //增加配置,登录的key是固定的不可以改变：loginUsername，loginPassword
        initParameters.put("loginUsername","admin");
        initParameters.put("loginPassword","123456");
        //允许谁可以访问
        initParameters.put("allow","");
        //禁止谁能访问：initParameters.put("DingJie","127.0.0.1");
        initParameters.put("DingJie","127.0.0.1");
        registrationBean.setInitParameters(initParameters);
        return registrationBean;
    }

    //filter 过滤器
    @Bean
    public FilterRegistrationBean webStatFilter(){
        FilterRegistrationBean registrationBean = new FilterRegistrationBean();
        registrationBean.setFilter(new WebStatFilter());
        //可以过滤什么请求
        HashMap<String, String> initParameters = new HashMap<>();
        initParameters.put("exclusions","*.js,*.css,/druid/*");

        registrationBean.setInitParameters(initParameters);
        return registrationBean;
    }
}

后台监控页面

03. Springboot-mybatis

• 3.1 加入依赖

<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.1.2</version>
</dependency>

• 3.2 创建User实体类
  

@Data
@NoArgsConstructor
@AllArgsConstructor
public class User {
    private Integer id;
    private String userName;
    private String passWord;
    private String realName;
}

• 3.3 创建新的Mapper接口
  

//这个注解表示了这是一个mybatis的mapper类
@Mapper
@Repository
public interface UserMapper {
    List<User> queryUserList();
    User queryUserById(int id);
    int addUser(User user);
    int updateUser(User user);
    int deleteUser(int id);
}

• 3.4 在resource下创建UserMapper.xml
  

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
		PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
		"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="edu.dj.mapper.UserMapper">
	<select id="queryUserList" resultType="User">
		select * from springboot_mybatis.user
	</select>

	<select id="queryUserById" resultType="User">
		select * from springboot_mybatis.user where id = #{id}
	</select>

	<insert id="addUser" parameterType="User">
		insert into springboot_mybatis.user(id, userName, passWord, realName) VALUES (#{id},#{userName},#{passWord},#{realName})
	</insert>

	<update id="updateUser" parameterType="User">
		update springboot_mybatis.user set userName=#{userName},realName=#{realName} where id=#{id}
	</update>

	<delete id="deleteUser" parameterType="int">
		delete from springboot_mybatis.user where id = #{id}
	</delete>
</mapper>

• 3.5 properties中配置整合mybatis(关键)

#整合mybatis（关键）
mybatis.type-aliases-package=edu.dj.pojo
mybatis.mapper-locations=classpath:mybatis/mapper/*.xml

• 3.6 controller中进行业务逻辑编写和测试
  

@RestController
public class UserController {

    @Autowired
    private UserMapper userMapper;

    //查询所有
    @GetMapping("/queryUserList")
    public List<User> queryUserList(){
        List<User> users = userMapper.queryUserList();
        for (User user : users){
            System.out.println(user);
        }
        return users;
    }
    //按ID查询
    @GetMapping("/queryUserById/{id}")
    public User queryUserById(@PathVariable("id")Integer id){
        User user = userMapper.queryUserById(id);
        return user;
    }
    //添加用户
    @GetMapping("/addUser")
    public String addUser(){
        userMapper.addUser(new User(4,"cbg","1234567","曹保国"));
        return "ADD_OK";
    }
    //修改用户
    @GetMapping("/updateUser")
    public String updateUser(){
        userMapper.updateUser(new User(4,"cbg","1234567","曹保国12138"));
        return "UPDATE_OK";
    }

    //根据id删除用户
    @GetMapping("/deleteUser/{id}")
    public String deleteUser(@PathVariable("id")Integer id){
        userMapper.deleteUser(id);
        return "DELETE_OK";
    }
}

springboot_整合JDBC_Druid数据源_MyBatis