mybatis

• • mybatis工具类
  • mybatis核心配置文件：mybatis-config.xml
  • pom文件
  • 编写代码
  • • 1. 实体类
    • 2. mapper接口
    • 3.mapper.xml
    • 4.StudentService
    • 5.StudentServiceImpl
    • 6.StudentController

在utils文件夹下

由SqlSessionFactoryBuilder创造sqlSessionFactory，再由后者创造SqlSession。而SqlSession可以执行sql语句（在这一部分，我们需要mybatis的核心配置文件，引出下面配置文件的编写）

package com.zhao.seckills.utils;


import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import java.io.IOException;
import java.io.InputStream;

//SqlSessionFactory → SqlSession
public class MybatisUtils {
	//由SqlSessionFactoryBuilder创造sqlSessionFactory，再由后者创造SqlSession。而SqlSession可以执行sql语句
	
    private static SqlSessionFactory sqlSessionFactory;

    static {
        try{
            //获取SqlSessionFactory对象
            String resource = "mybatis-config.xml";//初始就加载
            InputStream inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }


    //sqlSession完全包含了面向数据库所有的执行sql命令的方法
    public static SqlSession getSqlSession(){
        return sqlSessionFactory.openSession();
    }

}

在resource文件夹下

【注意】所有的mapper.xml文件都要在这里注册，才能真正操纵数据库

内容：

	mysql
	mysql-connector-java





	org.mybatis.spring.boot
	mybatis-spring-boot-starter
	1.3.2




	
	
		
		
			src/main/resources
			
				***.properties
			
			
			true
		
		
		
			src/main/java
			
			
				***.properties
			
			true
		
	

在pojo文件夹下

package com.zhao.seckills.pojo;

public class Student {
    int id;
    String firstName;
    String lastName;

    public Student(int id, String firstName, String lastName) {
        this.id = id;
        this.firstName = firstName;
        this.lastName = lastName;
    }

    public Student() {
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
}

在mapper包下
主要是数据库相关操作，与数据库交互

package com.zhao.seckills.mapper;

import com.zhao.seckills.pojo.Student;

import java.util.List;

public interface StudentMapper {
    List getStudents();
}

在mapper包下

要和mapper的接口相对应，也要注册到mybatis-config.xml中

    
    
        select * from Student
    

在service包下
调用Mapper中的方法，操控数据，并有些处理逻辑

package com.zhao.seckills.service;
import com.zhao.seckills.pojo.Student;
import java.util.List;

public interface StudentService {
    public List getStudents();
    public String getStudentsString();
    public String login(Student loginInfo) throws Exception;
}

在ServiceImpl包下
实现StudentService

@Service
public class StudentServiceImpl implements StudentService {
    SqlSession sqlSession;

    @Override
    public List getStudents() {
        try{
            sqlSession = MybatisUtils.getSqlSession();
            StudentMapper studentMapper = sqlSession.getMapper(StudentMapper.class);
            return studentMapper.getStudents();
        }
        catch(Exception e){
            e.printStackTrace();
        }finally{
            sqlSession.close();
        }

        return null;
    }
}

在controller包下
为前端提供接口，主要调用service层的方法

@RestController
@RequestMapping("/student")
public class StudentController {

    @Autowired
    private StudentService studentService;

    @GetMapping("/studentsList")
    public String list(Model model) {
        List list = studentService.getStudents();
        model.addAttribute("list", list);

        return studentService.getStudentsString();
    }
}