目录
3.springboot已经默认帮我们配置好了，去测试类测试。
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一、整合jdbc
1.创建项目，引入响应模块
2.编写yaml配置文件，连接数据库
spring:
datasource:
username: root
password: root
#?serverTimezone=UTC解决时区的报错
url: jdbc:mysql://localhost:3306/mybatis?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
driver-class-name: com.mysql.cj.jdbc.Driver3.springboot已经默认帮我们配置好了，去测试类测试。
@SpringBootTest
class Springboot04DataApplicationTests {
@Autowired
DataSource dataSource;
@Test
void contextLoads() throws SQLException {
// 查看默认数据源 class com.zaxxer.hikari.HikariDataSource
System.out.println(dataSource.getClass());
// 获得数据库连接
Connection connection = dataSource.getConnection();
System.out.println(connection);
connection.close();
}
}
关于数据源我们并不做介绍，有了数据库连接，显然就可以 CRUD 操作数据库了。但是我们需要先了解一个对象 JdbcTemplate
JdbcTemplate：
- 有了数据源，可以拿到数据库连接，有了连接，就可以使用原生的jdbc语句来操作数据库。
- 即使不使用第三方，JdbcTemplate也对其封装
- 数据库所有的方法都在JdbcTemplate
- spring默认配置好了JdbcTemplate，需要时只需注入
JdbcTemplate只要有以下几类方法：
- execute：可以实行sql语句，一般用于执行ddl语句
- update和batchUpdate：前者用于增删改，后者用于实行批处理
- query和queryFor***：用于查询
- call：用于执行储存过程、函数
4.编写类测试
@RestController
public class JDBCController {
@Autowired
JdbcTemplate jdbcTemplate;
// 查询数据库的所有信息
@GetMapping("/user")
public List<Map<String,Object>> userList(){
String sql = "select * from mybatis.user";
List<Map<String, Object>> maps = jdbcTemplate.queryForList(sql);
return maps;
}
@GetMapping("/add")
public String add(){
String sql="insert into mybatis.user(id, name, pwd) VALUES (10,'jdbc','00')";
jdbcTemplate.update(sql);
return "update-ok";
}
//修改用户信息
@GetMapping("/update/{id}")
public String updateUser(@PathVariable("id") int id){
//插入语句
String sql = "update employee set name=?,pwd=? where id="+id;
//数据
Object[] objects = new Object[2];
objects[0] = "小鱼";
objects[1] = "123";
jdbcTemplate.update(sql,objects);
//查询
return "updateOk";
}
}二、整合Druid数据源
1.依赖druid
<!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.1.21</version>
</dependency2.切换数据源
spring:
datasource:
username: root
password: root
url: jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf-8
driver-class-name: com.mysql.cj.jdbc.Driver
type: com.alibaba.druid.pool.DruidDataSource
3.可以设置初始化大小，最大最小值等
导入log4j依赖
<!-- https://mvnrepository.com/artifact/log4j/log4j -->
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>#Spring Boot 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
#配置监控统计拦截的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 地址：https://mvnrepository.com/artifact/log4j/log4j
filters: stat,wall,log4j
maxPoolPreparedStatementPerConnectionSize: 20
useGlobalDataSourceStat: true
connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5004.我们需要自己绑定我们配置的参数，然后添加到容器中
@Configuration
public class DruidConfig {
@ConfigurationProperties(prefix = "spring.datasource")
@Bean
public DataSource druidDataSource(){
return new DruidDataSource();
}
}去测试类测试，发现数据源已经更改为自己配置的
5.druid提供数据源监控功能
package com.kun.config;
import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.support.http.StatViewServlet;
import com.alibaba.druid.support.http.WebStatFilter;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import javax.sql.DataSource;
import java.util.HashMap;
@Configuration
public class DruidConfig {
@ConfigurationProperties(prefix = "spring.datasource")
@Bean
public DataSource druidDataSource(){
return new DruidDataSource();
}
// 后台监控
@Bean
public ServletRegistrationBean a(){
ServletRegistrationBean<StatViewServlet> bean = new ServletRegistrationBean<>(new StatViewServlet(), "/druid/*");
// 后台需要有人登录
HashMap<String, String> init = new HashMap<>();
// 增加配置
init.put("loginUsername","admin");
init.put("loginPassword","123456");
// 允许谁能访问
init.put("allow","");
bean.setInitParameters(init); //初始化参数
return bean;
}
}
配置完毕登录：http://localhost:8080/druid
6.druid提供过滤器
// 过滤器
@Bean
public FilterRegistrationBean webFilter(){
FilterRegistrationBean<Filter> bean = new FilterRegistrationBean<>();
bean.setFilter(new WebStatFilter());
HashMap<String, String> init = new HashMap<>();
init.put("exclusions","*.js,*.css./druid/*");
bean.setInitParameters(init);
return bean;
}三、整合mybatis
1.导入依赖
<!-- https://mvnrepository.com/artifact/org.mybatis.spring.boot/mybatis-spring-boot-starter -->
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.2.0</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</dependency>2.配置数据库连接信息
spring:
datasource:
username: root
password: 123456
#?serverTimezone=UTC解决时区的报错
url: jdbc:mysql://localhost:3306/springboot?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
driver-class-name: com.mysql.cj.jdbc.Driver
type: com.alibaba.druid.pool.DruidDataSource3.创建实体类
@Data
@NoArgsConstructor
@AllArgsConstructor
public class User {
private int id;
private String name;
private String pwd;
}4.创建mapper包，创建mapper接口
//这个注解
@Mapper
@Repository
public interface UserMapper {
List<User> queryUserList();
User queryUserByID(int id);
int addUser(User user);
int updateUser(User user);
int deleteUser(int id);
}
5.创建对应的映射文件
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.kun.mapper.UserMapper">
<select id="queryUserList" resultType="User">
select * from mybatis.user;
</select>
<select id="queryUserByID" resultType="User" parameterType="int">
select * from mybatis.user where id = #{id};
</select>
<insert id="addUser" parameterType="User">
insert into mybatis.user (id, name, pwd)
values (#{id},#{name},#{pwd});
</insert>
<update id="updateUser" parameterType="User">
update mybatis.user
set name=#{name},pwd =#{pwd}
where id=#{id};
</update>
<delete id="deleteUser" parameterType="int">
delete from mybatis.user where id=#{id}
</delete>
</mapper>6.进行测试
package com.kun.controller;
import com.kun.mapper.UserMapper;
import com.kun.pojo.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
@RestController
public class UserController {
//private final UserMapper userMapper;
//public UserController(UserMapper userMapper) {
// this.userMapper = userMapper;
//}
@Autowired
private UserMapper userMapper;
@GetMapping("/query")
public List<User> queryUserList(){
List<User> users = userMapper.queryUserList();
for (User user : users) {
System.out.println(user);
}
return users;
}
@GetMapping("/id/{id}")
public User queryUserByID(@PathVariable("id") int id){
User user = userMapper.queryUserByID(id);
return user;
}
@GetMapping("/add/{id}/{name}/{pwd}")
public List<User> addUser(@PathVariable("id") int id,@PathVariable("name") String name,@PathVariable("pwd") String pwd){
User user = new User(id, name, pwd);
userMapper.addUser(user);
List<User> users = userMapper.queryUserList();
return users;
}
@GetMapping("delete/{id}")
public String delete(@PathVariable("id") int id){
userMapper.deleteUser(id);
return "ok";
}
}