我们在用mybatis进行插入的时候需要返回一个自增的主键。
这个文章分为以下几步
1.建表
/*
Navicat Premium Data Transfer
Source Server : 本地
Source Server Type : MySQL
Source Server Version : 50720
Source Host : localhost:3306
Source Schema : mybatis
Target Server Type : MySQL
Target Server Version : 50720
File Encoding : 65001
Date: 29/05/2018 08:23:06
*/
SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;
-- ----------------------------
-- Table structure for tbl_employee
-- ----------------------------
DROP TABLE IF EXISTS `tbl_employee`;
CREATE TABLE `tbl_employee` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`last_name` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
`gender` char(1) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
`email` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 11 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;
SET FOREIGN_KEY_CHECKS = 1;
这个表有4个字段
分别是 id
last_name
gender
email
对应的实体类
private Integer id;
private String lastName;
private String email;
private String gender;
/**dao层**/
/**
* 添加一个员工信息
* @param employee 员工信息的实体类
*/
Long addEmp(Employee employee);
/**xml*/
<!--新增一条记录-->
<insert id="addEmp" parameterType="employee" >
INSERT INTO tbl_employee(last_name,email, gender) VALUES (#{lastName},#{email},#{gender})
</insert>
2.正常插入数据不返回主键id
现在我们写一个测试方法
@Test
public void test04() throws IOException {
// 1、获取sqlSessionFactory对象
SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
// 2、获取sqlSession对象并设置自动提交
SqlSession openSession = sqlSessionFactory.openSession(true);
try {
// 3、获取接口的实现类对象
//会为接口自动的创建一个代理对象，代理对象去执行增删改查方法
EmployeeMapper mapper = openSession.getMapper(EmployeeMapper.class);
Employee emp=new Employee(null,"tom","168@qq.com","1");
mapper.addEmp(emp);
//获取主键id
System.out.println("主键id的值:"+emp.getId());
} finally {
openSession.close();
}
}
3.返回主键id
如果需要返回主键id 我们只需要在xml 里面加上
<!--新增一条记录-->
<insert id="addEmp" parameterType="employee" useGeneratedKeys="true" keyProperty="id" >
INSERT INTO tbl_employee(last_name,email, gender) VALUES (#{lastName},#{email},#{gender})
</insert>
useGeneratedKeys="true"
keyProperty="id"
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