springBoot2.0整合myBatis(mysql)实现基本数据库操作

springBoot2.0整合myBatis(mysql)实现基本数据库操作

一.maven引入mybatis,jsp依赖

<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.3.0</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>com.github.pagehelper</groupId>
<artifactId>pagehelper</artifactId>
<version>4.1.6</version>
</dependency>
<!--jsp支持-->
<!-- servlet 依赖. -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
</dependency>
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-jasper</artifactId>
<scope>provided</scope>
</dependency>

2.配置application.properties配置文件

#JDBC连接本地mysql
spring.datasource.url= jdbc:mysql://localhost:3306/peng?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf-8
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

#配置springMVC视图解析器的文件后缀是jsp(解析后缀为jsp的页面)
spring.mvc.view.suffix=.jsp

###mybatis配置
#指定xml映射文件的路径
mybatis.mapper-locations=classpath:mappers/*.xml

#配置实体类的xml配置文件

<?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.seecen.dao.UsersDao">

<resultMap id="userMap"  type="com.seecen.entity.Users">
<id column="id" property="id"  />
<result column="name" property="name" ></result>
<result column="sex" property="sex"></result>
</resultMap>

<select id="queryUsers" resultMap="userMap">
select id, name, sex from iris_users
</select>
</mapper>

3.开始逻辑代码
3.1基层:entity
alt+insert快捷键添加get,set方法

public class Users {

private Integer id;
private String name;
private String sex;

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;
}

public String getSex() {
return sex;
}

public void setSex(String sex) {
this.sex = sex;
}
}

3.2 Dao层接口
dao层接口中的queryUsers方法名和mapper.xml配置文件中的方法标签中的ID一致

<select id="queryUsers" resultMap="userMap">
select id, name, sex from iris_users
</select>

import java.util.List;

@Mapper
public interface UsersDao {

public List<Users> queryUsers();
}

3.3:servcice层接口 和Dao层接口一致

import java.util.List;
public interface UsersServices {
public List<Users> queryUsers();
}

3.4:serviceImpl层,service的实现层

import com.seecen.dao.UsersDao;
import com.seecen.entity.Users;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UsersServicesImpl implements UsersServices {

@Autowired(required = false)
UsersDao usersDao;

@Override
public List<Users> queryUsers() {
return usersDao.queryUsers();
}
}

#@Service:加上这一行以后，将自动扫描路径下面的包，如果一个类带了@Service注解，将自动注册到Spring容器，不需要再在applicationContext.xml文件定义bean了，类似的还包括@Component、@Repository、@Controller。
#@Autowired:标记在 方法上的时候，它会根据类型去spring容器中寻找 对于的形参并且注入这里
3.5:Controller层(控制层)

import org.springframework.web.bind.annotation.RequestMapping;
import javax.servlet.http.HttpServletRequest;
import java.util.List;

@Controller
public class userController {

@Autowired
private UsersServices usersServices;

@RequestMapping("/iris")
public String queryUsers(HttpServletRequest request){
List<Users> usersList = usersServices.queryUsers();
request.setAttribute("usersList",usersList);
return "iris";
}
}

#@RequestMapping("/iris"):方法名 网页上可以输入
http://localhost:8080/iris来找到次方法
查询的是一个集合用 List usersList接收
usersServices.queryUsers();方法查询出的数据
用request.setAttribute发送到前台用键值对的方式

4.0:前台页面

<%--
Created by IntelliJ IDEA.
User: hpb
Date: 2018/12/4
Time: 15:44
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<c:forEach items="${usersList}" var="user">
编号:<span>${user.id}</span>
姓名:<span>${user.name}</span>
性别:<span>${user.sex}</span><br>
</c:forEach>
</body>
</html>

直接使用的jstl标签中的c:forEach 遍历usersList中的数据
5.0程序运行结果页面显示