######################################
###spring datasource
######################################
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.url=jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf-8&useSSL=false
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
###############################下面Spring的配置文件基本就不用修改了
spring.datasource.initialSize=5
spring.datasource.minIdle=5
spring.datasource.maxActive=20
spring.datasource.maxWait=60000
spring.datasource.timeBetweenEvictionRunsMillis=60000
spring.datasource.minEvictableIdleTimeMillis=300000
spring.datasource.validationQuery=SELECT 1 FROM DUAL
spring.datasource.testWhileIdle=true
spring.datasource.testOnBorrow=false
spring.datasource.testOnReturn=false
spring.datasource.poolPreparedStatements=true
spring.datasource.maxPoolPreparedStatementPerConnectionSize=20
spring.datasource.filters=stat,wall,log4j
spring.datasource.connectionProperties=druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
######################################
###spring thymeleaf
######################################
spring.thymeleaf.cache=false
######################################
###MyBatis
######################################
mybatis.mapper-locations=classpath:mapper/*Mapper.xml 

package com.example.demo.configBean;
import java.util.HashMap;
import java.util.Map;
import javax.sql.DataSource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
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 com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.support.http.StatViewServlet;
import com.alibaba.druid.support.http.WebStatFilter;
@Configuration
public class DruidConfiguration {
  private static final Logger log = LoggerFactory.getLogger(DruidConfiguration.class);
  @Bean
  public ServletRegistrationBean druidServlet() {
    log.info("init Druid Servlet Configuration ");
    ServletRegistrationBean servletRegistrationBean = new ServletRegistrationBean();
    servletRegistrationBean.setServlet(new StatViewServlet());
    servletRegistrationBean.addUrlMappings("/druid/*");
    Map<String, String> initParameters = new HashMap<String, String>();
    initParameters.put("loginUsername", "admin");// 用户名
    initParameters.put("loginPassword", "admin");// 密码
    initParameters.put("resetEnable", "false");// 禁用HTML页面上的“Reset All”功能
    initParameters.put("allow", ""); // IP白名单 (没有配置或者为空，则允许所有访问)
    // initParameters.put("deny", "192.168.20.38");// IP黑名单
    // (存在共同时，deny优先于allow)
    servletRegistrationBean.setInitParameters(initParameters);
    return servletRegistrationBean;
  }
  @Bean
  public FilterRegistrationBean filterRegistrationBean() {
    FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
    filterRegistrationBean.setFilter(new WebStatFilter());
    // 添加过滤规则
    filterRegistrationBean.addUrlPatterns("/*");
    // 添加不需要忽略的格式信息.
    filterRegistrationBean.addInitParameter("exclusions", "*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*");
    return filterRegistrationBean;
  }
  @Bean
  @ConfigurationProperties(prefix = "spring.datasource")
  public DataSource druidDataSource() {
    return new DruidDataSource();
  }
}

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

package com.example.demo.dao;
import org.apache.ibatis.annotations.Mapper;
import com.example.demo.entity.User;
@Mapper
public interface UserMapper {
  public User selectByPrimaryKey(Integer id);
}

package com.example.demo.entity;
public class User {
    private Integer id;
    private String name;
    private String username;
    private String password;
    private Integer sign;
    public User() {
  }
  @Override
  public String toString() {
    return "User [id=" + id + ", name=" + name + ", username=" + username + ", password=" + password + ", sign="
        + sign + "]";
  }
  public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name == null ? null : name.trim();
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username == null ? null : username.trim();
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password == null ? null : password.trim();
    }
    public Integer getSign() {
        return sign;
    }
    public void setSign(Integer sign) {
        this.sign = sign;
    }
}

package com.example.demo.handler;
import java.util.Map;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import com.example.demo.dao.UserMapper;
import com.example.demo.entity.User;
@Controller
public class HelloHandler {
  @Autowired
  private UserMapper  userMapper;
  @RequestMapping("/selectUser.action")
  public String selectUser(int id,Map<String,Object> map){
    User user=userMapper.selectByPrimaryKey(id);
    map.put("user", user);
    return "/success";
  }
}

<?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="com.example.demo.dao.UserMapper" >
  <resultMap id="BaseResultMap" type="com.example.demo.entity.User" >
    <id column="id" property="id" jdbcType="INTEGER" />
    <result column="name" property="name" jdbcType="VARCHAR" />
    <result column="username" property="username" jdbcType="VARCHAR" />
    <result column="password" property="password" jdbcType="VARCHAR" />
    <result column="sign" property="sign" jdbcType="INTEGER" />
  </resultMap>
  <sql id="Base_Column_List" >
    id, name, username, password, sign
  </sql>
  <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
    select 
    <include refid="Base_Column_List" />
    from user
    where id = #{id,jdbcType=INTEGER}
  </select>
</mapper>

package com.example.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class SpringBootMyBatisDruidApplication {
  public static void main(String[] args) {
    SpringApplication.run(SpringBootMyBatisDruidApplication.class, args);
  }
}