public interface UserMapper {
    public List<User> getUserListByNullParam();
    public List<User> getUesrListByUserName(String userName);
    public List<User> getUserList(User user);
    public List<User> getUserListByMap(Map<String,String> userMap);
    public List<User> getUserList();
    public int add(User user);
    public int modify(User user);

}
<?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.kgc.dao.UserMapper">
    <select id="count" resultType="int">
        select count(1) from smbms_user
    </select>
    <select id="userlist" resultType="User">-- 返回的是user类型

        select * from smbms_user
    </select>

    <select id="getUserListByNullParam" resultType="User">
        select * from smbms_user
    </select>
<!--    耿局用户名来查询列表，模糊查询 parameterType 参数类型  resultType返回类型-->
    <select id="getUesrListByUserName" parameterType="String" resultType="User">
        select * from smbms_user where userName like concat('%',#{userName},'%');
    </select>
<!--    查询用户列表-->
<!--    <select id="getUserList" parameterType="User" resultType="User">-->
<!--        select * from smbms_user where userName like  concat('%',#{userName},'%') and userRole = #{userRole};-->
<!--    </select>-->
<!--    Map查询-->
    <select id="getUserListByMap" parameterType="Map" resultType="User">
        select * from smbms_user where userName like  concat('%',#{userName},'%') and userRole = #{userRole};
    </select>
<!--    多表查询低级-->
<!--    <select id="getUserList" parameterType="User" resultType="User">-->
<!--        select u.*,r.roleName as userRoleName from smbms_user u,smbms_role r where userName like  concat('%',#{userName},'%') and userRole = #{userRole}-->
<!--        and u.userRole = r.id;-->
<!--    </select>-->
    <!--    多表查询Map-->
    <resultMap id="userList" type="User">
        <result column="id" property="id"/>
        <result column="userCode" property="userCode"/>
        <result column="userName" property="userName"/>
        <result column="phone" property="phone"/>
        <result column="userRole" property="userRole"/>
        <result column="roleName" property="userRoleName"/>
<!--        column字段名指向  property 属性名 手工映射-->
    </resultMap>
    <select id="getUserList" parameterType="User" resultMap="userList">
        select u.*,r.roleName  from smbms_user u,smbms_role r where userName like
         concat('%',#{userName},'%') and userRole = #{userRole}
        and u.userRole = r.id;
    </select>
<!--    插入insert-->
    <insert id="add" parameterType="com.kgc.pojo.User">
        insert into smbms_user(userCode,userName,userPassword,gender,birthday,phone,address,userRole,createdBy,creationDate) values(#{userCode},#{userName},#{userPassword},#{gender},#{birthday},#{phone},#{address},#{userRole},#{createdBy},#{creationDate})
    </insert>
<!--    修改-->
    <update id="modify" parameterType="com.kgc.pojo.User">
        update smbms_user set userCode=#{userCode},userPassword=#{userPassword}
        where id=#{id}
    </update>

</mapper>

dao

//Serializable 序列化 网络传输
public class User implements Serializable {
    private Integer id; //id
    private String userCode; //用户编码
    private String userName; //用户名称
    private String userPassword; //用户密码
    private Integer gender;  //性别
    private Date birthday;  //出生日期
    private String phone;   //电话
    private String address; //地址
    private Integer userRole;    //用户角色
    private Integer createdBy;   //创建者
    private Date creationDate; //创建时间
    private Integer modifyBy;     //更新者
    private Date modifyDate;   //更新时间
    private String userRoleName; //用户角色名称



    public String getUserRoleName() {
        return userRoleName;
    }
    public void setUserRoleName(String userRoleName) {
        this.userRoleName = userRoleName;
    }
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getUserCode() {
        return userCode;
    }
    public void setUserCode(String userCode) {
        this.userCode = userCode;
    }
    public String getUserName() {
        return userName;
    }
    public void setUserName(String userName) {
        this.userName = userName;
    }
    public String getUserPassword() {
        return userPassword;
    }
    public void setUserPassword(String userPassword) {
        this.userPassword = userPassword;
    }
    public Integer getGender() {
        return gender;
    }
    public void setGender(Integer gender) {
        this.gender = gender;
    }
    public Date getBirthday() {
        return birthday;
    }
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
    public String getPhone() {
        return phone;
    }
    public void setPhone(String phone) {
        this.phone = phone;
    }
    public String getAddress() {
        return address;
    }
    public void setAddress(String address) {
        this.address = address;
    }
    public Integer getUserRole() {
        return userRole;
    }
    public void setUserRole(Integer userRole) {
        this.userRole = userRole;
    }
    public Integer getCreatedBy() {
        return createdBy;
    }
    public void setCreatedBy(Integer createdBy) {
        this.createdBy = createdBy;
    }
    public Date getCreationDate() {
        return creationDate;
    }
    public void setCreationDate(Date creationDate) {
        this.creationDate = creationDate;
    }
    public Integer getModifyBy() {
        return modifyBy;
    }
    public void setModifyBy(Integer modifyBy) {
        this.modifyBy = modifyBy;
    }
    public Date getModifyDate() {
        return modifyDate;
    }
    public void setModifyDate(Date modifyDate) {
        this.modifyDate = modifyDate;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", userCode='" + userCode + '\'' +
                ", userName='" + userName + '\'' +
                ", userPassword='" + userPassword + '\'' +
                ", gender=" + gender +
                ", birthday=" + birthday +
                ", phone='" + phone + '\'' +
                ", address='" + address + '\'' +
                ", userRole=" + userRole +
                ", createdBy=" + createdBy +
                ", creationDate=" + creationDate +
                ", modifyBy=" + modifyBy +
                ", modifyDate=" + modifyDate +
                ", userRoleName='" + userRoleName + '\'' +
                '}';
    }
}

pojo

public class MybatisUtils {
    private static SqlSessionFactory sqlSessionFactory;
    static {
        String path = "mybatis-config.xml";
        try {
            InputStream is = Resources.getResourceAsStream(path);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
        } catch (IOException e) {
            e.printStackTrace();
        }


    }
    public static SqlSession getSqlSession(){
        //事务
        // 默认true 关闭 自动提交
        //false 开启
        return sqlSessionFactory.openSession();
    }
    public static void closeSqlSession(SqlSession sqlSession){
        if(null != sqlSession)
            sqlSession.close();
    }
}

util

public class TestUserMapper {
    @Test
    public void test01(){
        //1.记载核心配置文件
        String path = "mybatis-config.xml";
        InputStream is = null;
        try {
            is = Resources.getResourceAsStream(path);
            //2.mybatis的核心类
            SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
            SqlSession sqlSession = sqlSessionFactory.openSession();
            int result = sqlSession.selectOne("com.kgc.dao.UserMapper.count");
            System.out.println(result);
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
    @Test
    //使用工具类
    public void test02(){
        SqlSession sqlSession =  MybatisUtils.getSqlSession();
        List<User> userList = sqlSession.selectList("com.kgc.dao.UserMapper.userlist");
        for (User user : userList) {
            System.out.println(user);
        }
    }
    @Test
    //接口方式(以后全部用接口方式)
    public void test03(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        List<User> userList = sqlSession.getMapper(UserMapper.class).getUserListByNullParam();
        for (User user : userList) {
            System.out.println(user);
        }

    }
    @Test
    public  void test04(){
        String userName = "赵";
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        List<User> userList = sqlSession.getMapper(UserMapper.class).getUesrListByUserName(userName);
        for (User user : userList) {
            System.out.println(user);
        }
    }
    @Test
    //多条件查询
    public void test05(){
        User user = new User();
        user.setUserName("赵");
        user.setUserRole(2);
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        List<User> userList = sqlSession.getMapper(UserMapper.class).getUserList(user);
        for (User user1 : userList) {
            System.out.println(user1.getUserName());
        }
    }
    @Test
    //Map查询
    public void test06(){
        List<User> userList = new ArrayList<>();
        Map<String,String> userMap = new HashMap<>();
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        userMap.put("userName","赵");
        userMap.put("userRole","2");
        List<User> userListByMap = sqlSession.getMapper(UserMapper.class).getUserListByMap(userMap);
        for (User user : userListByMap) {
            System.out.println(user.getUserName());
        }


    }
    @Test
    public void test07(){
        User user = new User();
        user.setUserName("赵");
        user.setUserRole(2);
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        List<User> userList = sqlSession.getMapper(UserMapper.class).getUserList(user);
        for (User user1 : userList) {
            System.out.println(user1.getUserName()+"*******"+user1.getUserRoleName()+
                    "*******"+user1.getAddress());
        }
    }
    @Test
    public void testAdd(){
        int count = 0;
        SqlSession sqlSession = null;
        User user = null;
        try{
            sqlSession = MybatisUtils.getSqlSession();
            user = new User();
            user.setUserCode("test001");
            user.setUserName("测试001");
            user.setAddress("测试地址");
            user.setBirthday(new SimpleDateFormat("yyyy-MM-dd").parse("2019-10-21"));
            user.setGender(1);
            user.setUserPassword("123456");
            user.setUserRole(2);
            user.setCreatedBy(1);
            user.setCreationDate(new Date());
            count = sqlSession.getMapper(UserMapper.class).add(user);
            //int i = 2/0;
            sqlSession.commit();
        }catch (Exception e){
            e.printStackTrace();
            sqlSession.rollback();
            count = 0;



        }finally {
            MybatisUtils.closeSqlSession(sqlSession);
        }
        System.out.println(count);
    }
    @Test
    public void testModify(){
        int count = 0;
        SqlSession sqlSession = null;
        User user = null;
        try{
            sqlSession = MybatisUtils.getSqlSession();
            user = new User();
            user.setId(16);
            user.setUserPassword("654321");
            user.setUserCode("009");
            count = sqlSession.getMapper(UserMapper.class).modify(user);
            sqlSession.commit();
        }catch (Exception e){
            //sqlSession.rollback();
            e.printStackTrace();
        }finally {
            MybatisUtils.closeSqlSession(sqlSession);
        }
        System.out.println(count);
    }
}

test

<?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">
<configuration>
    <!--加载数据库配置信息-->
    <properties resource="database.properties">
<!--        <property name="driver" value="com.mysql.cj.jdbc.Driver"></property>-->
<!--        <property name="url" value="jdbc:mysql://localhost:3306/smbms?useUnicode=true&characterEncoding=utf8&serverTimezone=GMT%2B8&useSSL=false&zeroDateTimeBehavior=CONVERT_TO_NULL"></property>-->
<!--        <property name="username" value="root"></property>-->
<!--        <property name="password" value=""></property>-->
    </properties>
    <!--设置日记行为-->
    <settings>
        <setting name="logImpl" value="LOG4J"></setting>
<!--        延迟加载-->
        <setting name="lazyLoadingEnabled" value="false"></setting>
<!--        禁止自动匹配-->
        <setting name="autoMappingBehavior" value="NONE"></setting>

    </settings>
    <!--設置別名-->
    <typeAliases>
        <!--不推荐使用，当我们有很多的实体类的时候，这里配置的也很冗余
        <typeAlias type="cn.kgc.pojo.User"></typeAlias>-->
        <package name="com.kgc.pojo"></package>
    </typeAliases>
    <!--配置运行环境-->
<!--    dev开发环境-->
    <environments default="dev">
        <environment id="dev">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="${driver}"/>
                <property name="url" value="${url}"/>
                <property name="username" value="${username}"/>
                <property name="password" value="${password}"/>
            </dataSource>
        </environment>
<!--        测试环境-->
        <environment id="test">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="${driver}"/>
                <property name="url" value="${url}"/>
                <property name="username" value="${username}"/>
                <property name="password" value="${password}"/>
            </dataSource>
        </environment>
<!--        生产环境-->
        <environment id="pro">
            <transactionManager type=""></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="${driver}"/>
                <property name="url" value="${url}"/>
                <property name="username" value="${username}"/>
                <property name="password" value="${password}"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="com/kgc/dao/UserMapper.xml"></mapper>
    </mappers>
</configuration>