Mybatis动态SQL

Mybatis，在带注解的映射器接口类中使用动态SQL，可使用script元素，即：。

案例代码

Model

package com.what21.mybatis.model;

import lombok.Data;

@Data
public class Employee {

    // ID
    private Integer id;
    // 名称
    private String name;
    // 邮箱
    private String email;
    // 性别
    private String gender;
    // 年龄
    private Integer age;

}

Mapper<映射器接口>

package com.what21.mybatis.demo03.mapper;

import com.what21.mybatis.model.Employee;
import org.apache.ibatis.annotations.*;

import java.util.List;

public interface EmployeeMapper {

    @Select(value = "select * from `employee` where id = #{id}")
    @ResultType(Employee.class)
    public Employee findEmployeeById(Integer id);

    @Update(value = "")
    public int updateEmployee(Employee employee);

    @Delete(value = "")
    public int deleteEmployeeByIds(@Param("idList") List idList);

}

配置文件：

<?xml version="1.0" encoding="UTF-8" ?>



    
        
        
        
    

    
        
    

    
        
            
            
            
        
    

    
        
            
            
                
                
                
                
            
        
    

    
        
    

测试类：

package com.what21.mybatis.demo03;

import com.what21.mybatis.demo03.mapper.EmployeeMapper;
import com.what21.mybatis.model.Employee;
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.Reader;
import java.util.Arrays;
import java.util.List;

public class MybatisDemoMain {

    /**
     * 创建sessionFactory
     *
     * @param mybatisConfig
     * @return
     */
    private static SqlSessionFactory getSessionFactory(String mybatisConfig) {
        SqlSessionFactory sessionFactory = null;
        try {
            Reader reader = Resources.getResourceAsReader(mybatisConfig);
            sessionFactory = new SqlSessionFactoryBuilder().build(reader);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return sessionFactory;
    }

    public static void main(String[] args) {
        String resource = "com/what21/mybatis/demo03/mybatisConfig.xml";
        // 从SessionFactory中获取SqlSession
        SqlSession sqlSession = getSessionFactory(resource).openSession();
        // Mapper
        EmployeeMapper employeeMapper = sqlSession.getMapper(EmployeeMapper.class);
        // select操作
        Employee findEmployee = employeeMapper.findEmployeeById(2);
        System.out.println(findEmployee);
        findEmployee.setName("学习测试demo");
        findEmployee.setEmail("leran@demo.com");
        findEmployee.setAge(34);
        findEmployee.setGender("1");
        int updateOperate = employeeMapper.updateEmployee(findEmployee);
        System.out.println("update操作结果：" + updateOperate);
        List idsList = Arrays.asList(findEmployee.getId());
        // delete操作
        int deleteOperate = employeeMapper.deleteEmployeeByIds(idsList);
        // SQL正确，没有删除任何一条数据，返回结果为：0
        System.out.println("delete操作结果：" + deleteOperate);
        // 提交
        //sqlSession.commit();
    }

}