Mybatis参数处理的几种方法小结

<dependencies>
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.5.10</version>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.38</version>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.13.2</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.projectLombok</groupId>
        <artifactId>lombok</artifactId>
        <version>1.18.26</version>
    </dependency>
</dependencies>

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/hqyj03?useUnicode=true&characterEncoding=utf8&useSSL=false&serverTimeZone=Asia/Shanghai
password=yjg
username=root

<setting name="mapUnderscoreToCamelCase" value="true"/> 

<setting name="logImpl" value="STDOUT_LOGGING"/> 

<!--设置映射类型别名-->
    <typeAliases>
       <!--设置pojo包下的类型别名-->
        <package name="com.yjg.mybatis.pojo"/>
    </typeAliases>

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<!--在configuration配置内容时，有顺序限制-->
<configuration>
      <!--读取jdbc.properties配置文件-->
 <properties resource="jdbc.properties"></properties>
<settings>
    <!--配置sql日志打印-->
    <setting name="logImpl" value="STDOUT_LOGGING"/>
    <!--下划线驼峰映射stu_name映射stuName-->
    <setting name="mapUnderscoreToCamelCase" value="true"/>
</settings>
    <!--设置映射类型别名-->
    <typeAliases>
       <!--设置pojo包下的类型别名-->
        <package name="com.yjg.mybatis.pojo"/>
    </typeAliases>
    <!--mybatis环境，default属性指定一个环境-->
    <environments default="development">
        <!--id属性自定义的环境唯一标识符-->
        <environment id="development">
            <!--指定使用jdbc事务管理-->
            <transactionManager type="JDBC"/>
            <!--使用mybatis内部带连接池功能的数据源-->
            <dataSource type="POOLED">
                <!--获取配置驱动-->
                <property name="driver" value="${driver}"/>
                <!--获取配置url-->
                <property name="url" value="${url}"/>
                <!--获取配置账号-->
                <property name="username" value="${username}"/>
                <!--获取配置密码-->
                <property name="password" value="${password}"/>
            </dataSource>
        </environment>
    </environments>
    <!--映射器，映射器的 XML 映射文件包含了 SQL 代码和映射定义信息-->
    <mappers>
        <mapper resource="com/yjg/mybatis/mapper/StudentMapper.xml"/>
    </mappers>
</configuration>

CREATE TABLE `student` (
  `stu_id` int(11) NOT NULL AUTO_INCREMENT,
  `stu_name` varchar(255) DEFAULT NULL,
  `stu_age` varchar(255) DEFAULT NULL,
  `stu_salary` decimal(10,2) DEFAULT NULL,
  `stu_birth` date DEFAULT NULL,
  `create_time` datetime DEFAULT NULL,
  PRIMARY KEY (`stu_id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;

import lombok.Data;
import java.util.Date;
@Data
//@Alias 注解是 MyBatis 提供的一个注解，用于为类或接口指定一个别名。
//@Alias("s")
public class Student {
    private Integer stuId;
    private String  stuName;
    private Integer stuAge;
    private Double  stuSalary;
    private Date  stuBirth;
    private Date createTime;
}

public interface StudentMapper {
    //插入用户
    int insertStudent();
    //查询全部类型
    List<Student> queryStudent();
    //通过id查询学生,传递单个参数
    Student queryStudentById(Integer id);
   /*
   通过名字和age进行查询
     1.方法中的参数会将存储到map集合中，key值设置为arg0 , arg1.....或者设置为param1, param2. ...
     2.sql语句中是通过#{map的key值}来获取到参数值,例如#{arg0}
     3.可以通过@Param注解更改参数在map中的key
     @Param("name")可以修改名称
   */
    Student queryStudentByNameAndAge(@Param("name") String name,@Param("age") int age);
}

<?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.yjg.mybatis.mapper.StudentMapper">
    <insert id="insertStudent">
        insert into student values(null, 'zhangsan',18,' 200','2020-01-01 ' , now())
    </insert>
    <select id="queryStudent" parameterType="integer" resultType="Student">
              select * from student;
    </select>
      <!--拿到方法的形参，单个参数，#{id}-->
    <select id="queryStudentById" resultType="Student">
          select * from student where stu_id=#{id}
    </select>
     <!--拿到参数的值，多个参数的时候-->
    <select id="queryStudentByNameAndAge" resultType="student">
          select * from student where stu_name=#{name} and stu_age=#{age};
    </select>
</mapper>

public class Test1 {
    SqlSession sqlSession;
    @Before
    public void test1() throws Exception{
        InputStream inputStream = Resources.getResourceAsStream("mybatis.xml");
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        SqlSessionFactory build = builder.build(inputStream);
       sqlSession = build.openSession(true);
    }
     //    添加数据
    @Test
    public void test2(){
        StudentMapper mapper = sqlSession.getMapper(StudentMapper.class);
        int i = mapper.insertStudent();
        System.out.println(i);
    }
     //    查询所有学生
    @Test
    public void test3(){
        StudentMapper mapper = sqlSession.getMapper(StudentMapper.class);
        List<Student> students = mapper.queryStudent();
        students.forEach(System.out::println);
    }
    //    根据id查询
    @Test
    public void test4(){
        StudentMapper mapper = sqlSession.getMapper(StudentMapper.class);
        Student student = mapper.queryStudentById(2);
        System.out.println(student);
    }
    //    根据多个参数查询
    @Test
    public void test5(){
        StudentMapper mapper = sqlSession.getMapper(StudentMapper.class);
        Student student = mapper.queryStudentByNameAndAge("kun", 18);
        System.out.println(student);
    }
}