第一章：Mybatis开发环境搭建，集成mysql数据库

一）开发前准备

下载jar：

mybatis-3.4.6.jar

mysql-connector-java-5.1.34-bin.jar

 

二）Mybatis开发环境搭建

1） 创建一个Dynamic Web Project，名称为：xm-mybatis-one，项目结构图如下：

2）创建员工实体文件EmployeeEntity.java

package com.xm.mybatis.entity;

/**
 * 员工表 entity
 * @author ouyangjun
 */
public class EmployeeEntity {
	
    private Integer empId;
    private String empName;
    private String empNO;
    private Long createDate;

    public Integer getEmpId() {return empId;}
    public void setEmpId(Integer empId) {this.empId = empId;}

    public String getEmpName() {return empName;}
    public void setEmpName(String empName) {this.empName = empName;}

    public String getEmpNO() {return empNO;}
    public void setEmpNO(String empNO) {this.empNO = empNO;}

    public Long getCreateDate() {return createDate;}
    public void setCreateDate(Long createDate) {this.createDate = createDate;}
}

3）创建员工实体映射文件EmployeeEntity.xml

    
        insert into employee(emp_id,emp_name,emp_no,create_date)
        values(#{empId}, #{empName}, #{empNO}, #{createDate})
    
	
    
        select 
            emp_id as empId,
            emp_name as empName,
            emp_no as empNO,
            create_date as createDate
        from employee where emp_id = #{empId}
    
	
    
		
    
	
    
    
        delete from employee where 1=1
        and emp_Id in 
        
            #{item}
        
    

4）创建员工接口文件EmployeeDAO.java

package com.xm.mybatis.dao;

import com.xm.mybatis.entity.EmployeeEntity;

public interface EmployeeDAO {

    /**
     * 根据empId获取员工信息
     */
    EmployeeEntity getEmployeeByEmpId(String empId);
	
    /**
     * 添加员工
     */
    int addEmployee(EmployeeEntity entity);
	
    /**
     * 根据empId修改用户信息
     */
    int updateEmployee(EmployeeEntity entity);
	
    /**
     * 根据empId删除用户
     */
    int deleteEmployeeEntityByEmpId(String[] empIds);
}

5）创建mybatis核心配置文件mybatis.cfg.xml。注：该文件名可随意，在读取配置时指定。

6）创建获取SqlSessionFactory的工具类SessionUtils.java。通过单列模式实现。

package com.xm.mybatis.utils;

import java.io.IOException;
import java.io.Reader;

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

public class SessionUtils {
	
    /**
     * 内部类单列模式实现读取mybatis配置文件
     * @author ouyangjun
     */
    private static class LasyHolder {
        private static Reader READER = getReader();
		
        public static Reader getReader() {
            try {
                System.out.println("==>读取mybatis.cfg.xml文件中的配置!");
                // 读取mybatis配置文件
                return Resources.getResourceAsReader("mybatis.cfg.xml");
            } catch (IOException e) {
                System.out.println("==>读取mybatis.cfg.xml文件中的配置错误 error!");
                e.printStackTrace();
            }
            return null;
        }
    }
	
    /**
     * 获取配置文件对象
     */
    public static Reader getReader() {
        return LasyHolder.READER;
    }
	
    /**
     * 线程本地配置声明
     */
    public static ThreadLocal threadLocal = new ThreadLocal();
	
    /**
     * ThreadLocal获取SqlSessionFactory
     */
    public static SqlSessionFactory getSqlSessionFactory() {
        // 获取sqlSessionFactory
        SqlSessionFactory sqlSessionFactory = threadLocal.get();
		
        System.out.println("sqlSessionFactory: " + sqlSessionFactory);
        if (sqlSessionFactory == null) {
            System.out.println("sqlSessionFactory is null 重新获取SqlSessionFactory!");
            // 读取mybatis配置文件
            Reader reader = SessionUtils.getReader();
			
            // 重新创建SqlSessionFactory
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
			
            // 把sqlSessionFactory添加到ThreadLocal中
            threadLocal.set(sqlSessionFactory);
        }
		
        // 返回
        return sqlSessionFactory;
    }
}

7）添加员工新增测试类AddEmployeeTest.java，执行该方法之后可自行到mysql数据库查看。

package com.xm.mybatis.test;

import java.util.Date;

import org.apache.ibatis.session.SqlSession;

import com.xm.mybatis.dao.EmployeeDAO;
import com.xm.mybatis.entity.EmployeeEntity;
import com.xm.mybatis.utils.SessionUtils;

public class AddEmployeeTest {

    public static void main(String[] args) {
        SqlSession sqlSession = null;
        try {
            sqlSession = SessionUtils.getSqlSessionFactory().openSession();
			
            // 初始化接口
            EmployeeDAO employeeDAO = sqlSession.getMapper(EmployeeDAO.class);
			
            EmployeeEntity emp = new EmployeeEntity();
            emp.setEmpId(100000);
            emp.setEmpName("ouyangjun");
            emp.setEmpNO("333333");
            emp.setCreateDate(new Date().getTime());
			
            // 持久化
            employeeDAO.addEmployee(emp);
			
            emp = new EmployeeEntity();
            emp.setEmpId(200000);
            emp.setEmpName("xm");
            emp.setEmpNO("888888");
            emp.setCreateDate(new Date().getTime());
			
            // 持久化
            employeeDAO.addEmployee(emp);
			
            // 提交事务
            sqlSession.commit();
            System.out.println("==>员工数据持久化成功!");
        } catch (Exception e){
            e.printStackTrace();
            sqlSession.rollback();
            System.out.println("==>员工数据持久化失败!");
        } finally {
            sqlSession.close();
            System.out.println("==>事务关闭!");
        }
    }
}

8）添加员工查询测试类GetEmployeeTest.java

package com.xm.mybatis.test;

import java.io.IOException;

import org.apache.ibatis.session.SqlSession;

import com.xm.mybatis.dao.EmployeeDAO;
import com.xm.mybatis.entity.EmployeeEntity;
import com.xm.mybatis.utils.SessionUtils;

public class GetEmployeeTest {

    public static void main(String[] args) throws IOException {
		
        // 获取SqlSession
        SqlSession sqlSession = SessionUtils.getSqlSessionFactory().openSession();
		
        // 初始化接口
        EmployeeDAO employeeDAO = sqlSession.getMapper(EmployeeDAO.class);
		
        EmployeeEntity entity = employeeDAO.getEmployeeByEmpId("100000");
        if(entity!=null){
            System.out.println(entity.getEmpId()+" "+entity.getEmpName()+" "+entity.getEmpNO());
        } else {
            System.out.println("根据empId未查询到数据!");
        }
		
        System.out.println("----------测试SqlSessionFactory单列----------");
		
        sqlSession = SessionUtils.getSqlSessionFactory().openSession();
        // 初始化接口
        employeeDAO = sqlSession.getMapper(EmployeeDAO.class);
        entity = employeeDAO.getEmployeeByEmpId("100000");
        if(entity!=null){
            System.out.println(entity.getEmpId()+" "+entity.getEmpName()+" "+entity.getEmpNO());
        } else {
            System.out.println("根据empId未查询到数据!");
        }
        sqlSession.close();
    }
}

查询效果图如下：

9）添加员工删除测试类DeleteEmployeeTest.java

package com.xm.mybatis.test;

import java.io.IOException;

import org.apache.ibatis.session.SqlSession;

import com.xm.mybatis.dao.EmployeeDAO;
import com.xm.mybatis.utils.SessionUtils;

public class DeleteEmployeeTest {

    public static void main(String[] args) throws IOException {
        SqlSession sqlSession = null;
        try {
            sqlSession = SessionUtils.getSqlSessionFactory().openSession();
			
            // 初始化接口
            EmployeeDAO employeeDAO = sqlSession.getMapper(EmployeeDAO.class);
			
            String[] empIds = {"100000","200000"};
            employeeDAO.deleteEmployeeEntityByEmpId(empIds);
			
            sqlSession.commit();
            System.out.println("==>员工数据删除成功!");
        } catch (Exception e){
            e.printStackTrace();
            sqlSession.rollback();
            System.out.println("==>员工数据删除失败!");
        } finally {
            sqlSession.close();
            System.out.println("==>事务关闭!");
        }
    }
}

 

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