• mybatis实战：二、mybatis xml 方式的基本用法

    注释都在代码里，最好复制了再看！

    1.创建表

    1. CREATE TABLE sys_user(
    2. id BIGINT NOT NULL AUTO_INCREMENT COMMENT '用户 ID',
    3. user_name VARCHAR(50) COMMENT '用户名',
    4. user_password VARCHAR(50) COMMENT '密码',
    5. user_email VARCHAR(50) COMMENT '邮箱',
    6. user_info TEXT COMMENT '简介',
    7. head_img BLOB COMMENT '头像',
    8. create_time DATETIME COMMENT '创建时间',
    9. PRIMARY KEY (id) 
    10. );
    11. ALTER TABLE sys_user COMMENT '用户表';
    12.  
    13. CREATE TABLE sys_role(
    14. id BIGINT NOT NULL AUTO_INCREMENT COMMENT '角色 ID',
    15. role_name VARCHAR(50) COMMENT '角色名',
    16. enabled INT COMMENT '有效标志',
    17. create_by BIGINT COMMENT '创建人',
    18. create_time DATETIME COMMENT '创建时间',
    19. PRIMARY KEY (id) 
    20. );
    21. ALTER TABLE sys_role COMMENT '角色表';
    22.  
    23. CREATE TABLE sys_prvilege(
    24. id BIGINT NOT NULL AUTO_INCREMENT COMMENT '权限  ID',
    25. privilege_name VARCHAR(50) COMMENT '权限名称',
    26. privilege_url VARCHAR (200) COMMENT '权限 URL',
    27. PRIMARY KEY (id) 
    28. );
    29. ALTER TABLE sys_prvilege COMMENT '权限表';
    30.  
    31. CREATE TABLE sys_user_role( 
    32. user_id BIGINT COMMENT '用户 ID ',
    33. role_id BIGINT COMMENT '角色 ID'
    34. );
    35. ALTER TABLE sys_user_role COMMENT '用户角色关联表';
    36.  
    37. CREATE TABLE sys_role_prvilege(
    38. role_id BIGINT COMMENT '角色ID',
    39. privilege_id BIGINT COMMENT 'ID' 
    40. );
    41. ALTER TABLE sys_role_prvilege COMMENT '角色权限关联表';

    2.插入数据

    1. CREATE TABLE sys_user(
    2. id BIGINT NOT NULL AUTO_INCREMENT COMMENT '用户 ID',
    3. user_name VARCHAR(50) COMMENT '用户名',
    4. user_password VARCHAR(50) COMMENT '密码',
    5. user_email VARCHAR(50) COMMENT '邮箱',
    6. user_info TEXT COMMENT '简介',
    7. head_img BLOB COMMENT '头像',
    8. create_time DATETIME COMMENT '创建时间',
    9. PRIMARY KEY (id) 
    10. );
    11. ALTER TABLE sys_user COMMENT '用户表';
    12.  
    13. CREATE TABLE sys_role(
    14. id BIGINT NOT NULL AUTO_INCREMENT COMMENT '角色 ID',
    15. role_name VARCHAR(50) COMMENT '角色名',
    16. enabled INT COMMENT '有效标志',
    17. create_by BIGINT COMMENT '创建人',
    18. create_time DATETIME COMMENT '创建时间',
    19. PRIMARY KEY (id) 
    20. );
    21. ALTER TABLE sys_role COMMENT '角色表';
    22.  
    23. CREATE TABLE sys_prvilege(
    24. id BIGINT NOT NULL AUTO_INCREMENT COMMENT '权限  ID',
    25. privilege_name VARCHAR(50) COMMENT '权限名称',
    26. privilege_url VARCHAR (200) COMMENT '权限 URL',
    27. PRIMARY KEY (id) 
    28. );
    29. ALTER TABLE sys_prvilege COMMENT '权限表';
    30.  
    31. CREATE TABLE sys_user_role( 
    32. user_id BIGINT COMMENT '用户 ID ',
    33. role_id BIGINT COMMENT '角色 ID'
    34. );
    35. ALTER TABLE sys_user_role COMMENT '用户角色关联表';
    36.  
    37. CREATE TABLE sys_role_prvilege(
    38. role_id BIGINT COMMENT '角色ID',
    39. privilege_id BIGINT COMMENT 'ID' 
    40. );
    41. ALTER TABLE sys_role_prvilege COMMENT '角色权限关联表';
    42.  
    43. INSERT INTO sys_user VALUES ('2','admin','123456','admin@mybatis.tk','管理员',NULL,'2016-04-01 17:00:58'); 
    44. INSERT INTO sys_user VALUES ('1001','test','123456','test@mybatis.tk','测试用户',NULL,'2016-04-01 17:00:58'); 
    45. INSERT INTO sys_role VALUES ('1','管理员','1','1','2016-04-01 17:02:14'); 
    46. INSERT INTO sys_role VALUES ('2','普通用户','1','1','2016-04-01 17:02:34');
    47. INSERT INTO sys_user_role VALUES ('1','1'); 
    48. INSERT INTO sys_user_role VALUES ('1','2');  
    49. INSERT INTO sys_user_role VALUES ('3','2'); 
    50. INSERT INTO sys_prvilege VALUES ('1','用户管理','/users'); 
    51. INSERT INTO sys_prvilege VALUES ('2','角色管理','/roles'); 
    52. INSERT INTO sys_prvilege VALUES ('3','系统日志','/logs'); 
    53. INSERT INTO sys_prvilege VALUES ('4','人员维护','/persons'); 
    54. INSERT INTO sys_prvilege VALUES ('5','单位维护','/companies'); 
    55. INSERT INTO sys_role_prvilege VALUES ('1','l'); 
    56. INSERT INTO sys_role_prvilege VALUES ('1','1001'); 
    57. INSERT INTO sys_role_prvilege VALUES ('1','2');  
    58. INSERT INTO sys_role_prvilege VALUES ('2','4'); 
    59. INSERT INTO sys_role_prvilege VALUES ('2','5');

    3.创建实体类

    1. package tk.mybatis.simple.model;
    2.  
    3. import java.util.Date;
    4.  
    5. import lombok.Data;
    6.  
    7. @Data
    8. public class SysUser {
    9.     private Long id;
    10.     private String userName;
    11.     private String userPassword;
    12.     private String userInfo;
    13.     private byte[] headImg;
    14.     private Date createTime;
    15.     private String userEmail;
    16. }

    @Date可以省略get、set方法，要导入依赖、下载插件才可以使用

    1. <dependency>
    2.             <groupId>org.projectlombok</groupId>
    3.             <artifactId>lombok</artifactId>
    4.             <version>1.18.24</version>
    5.         </dependency>

    1. package tk.mybatis.simple.model;
    2.  
    3. import lombok.Data;
    4.  
    5. @Data
    6. public class SysUserRole {
    7.     private Long userId;
    8.     private Long roleId;
    9. }

    4.Mapper

    创建一下文件

    xml：

    需要注意 是＜mapper ＞根标签 name space 属性。当 app 接口和 XM 文件关联的时候，命名空间口amespace 值就需要配置成接口的全限定名称，例如 UserMapper 接口对 应的 tk.mybat. simple.mapper.UserMapper内部就是通过这个值将接口和XML 关联起来的。

    1. "1.0" encoding="UTF-8" ?>
    2. mapper
    3.         PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
    4.         "https://mybatis.org/dtd/mybatis-3-mapper.dtd">
    9. <mapper namespace="tk.mybatis.simple.mapper.UserMapper">
    10. mapper>

     mybatis-config.xml

    1. <mappers>
    2.         <mapper resource="mapper/CountryMapper.xml"/>
    3.         <mapper resource="mapper/UserMapper.xml"/>
    4.         <mapper resource="mapper/RoleMapper.xml"/>
    5.         <mapper resource="mapper/PrivilegeMapper.xml"/>
    6.         <mapper resource="mapper/UserRoleMapper.xml"/>
    7.         <mapper resource="mapper/RolePrivilegeMapper.xml"/>
    8.     </mappers>

    5.UserMapper.xml

    1. "1.0" encoding="UTF-8" ?>
    2. mapper
    3.         PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
    4.         "https://mybatis.org/dtd/mybatis-3-mapper.dtd">
    9. <mapper namespace="tk.mybatis.simple.mapper.UserMapper">
    10.     
    11.     
    12.     <resultMap id="userMap" type="tk.mybatis.simple.model.SysUser">
    14.         <id property="id" column="id"/>
    15.         <result property="userName" column="user_name"/>
    16.         <result property="userPassword" column="user_password"/>
    17.         <result property="userEmail" column="user_email"/>
    18.         <result property="userInfo" column="user_info"/>
    19.         <result property="headImg" column="head_img" jdbcType="BLOB"/>
    20.         <result property="createTime" column="create_time" jdbcType="TIMESTAMP"/>
    33.     resultMap>
    35.     <select id="selectById" resultMap="userMap">
    37.         select * from sys_user where id = #{id}
    39.     select>
    41.     <select id="selectAll1" resultType="tk.mybatis.simple.model.SysUser" >
    42.     select id,
    43.     user_name userName,
    44.     user_password userPassword,
    45.     user_email userEmail,
    46.     user_info userInfo ,
    47.     head img headImg,
    48.     create_time createTime
    49.     from sys_user
    50. select>
    52.  
    53.     <select id= "selectAll2" resultType="tk.mybatis.simple.model.SysUser" >
    54.     select id, user_name , user_password, user_email , user_info, head_img, create_time from sys_user
    55. select>
    56. mapper>

    6.BaseMapperTest

    1. package tk.mybatis.simple.mapper;
    2.  
    3. import org.apache.ibatis.io.Resources;
    4. import org.apache.ibatis.session.SqlSession;
    5. import org.apache.ibatis.session.SqlSessionFactory;
    6. import org.apache.ibatis.session.SqlSessionFactoryBuilder;
    7. import org.junit.BeforeClass;
    8.  
    9. import java.io.IOException;
    10. import java.io.Reader;
    11.  
    12. public class BaseMapperTest {
    13.     private static SqlSessionFactory sqlSessionFactory;
    14.     @BeforeClass
    15.     public static void init () {
    16.         try {
    17.             Reader reader = Resources.getResourceAsReader ("mybatis-config.xml");
    18.             sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
    19.             reader.close();
    20.         } catch (IOException ignore) {
    21.             ignore.printStackTrace();
    22.         }
    23.     }
    24.     public SqlSession getSqlSession () {
    25.         return sqlSessionFactory.openSession();
    26.     }
    27. }

    7.CountryMapperTest

    1. package tk.mybatis.simple.mapper;
    2.  
    3. import org.apache.ibatis.io.Resources;
    4. import org.apache.ibatis.session.SqlSession;
    5. import org.apache.ibatis.session.SqlSessionFactory;
    6. import org.apache.ibatis.session.SqlSessionFactoryBuilder;
    7. import org.junit.Assert;
    8. import org.junit.BeforeClass;
    9. import org.junit.Test;
    10. import tk.mybatis.simple.model.Country;
    11. import tk.mybatis.simple.model.SysUser;
    12.  
    13. import java.io.IOException;
    14. import java.io.Reader;
    15. import java.util.List;
    16.  
    17. public class CountryMapperTest extends BaseMapperTest {
    18.     private static SqlSessionFactory sqlSessionFactory;
    19.  
    20. //    @BeforeClass
    21. //    public static void init() {
    22. //        try {
    23.             通过 Resources 工具类将 ti -config.xm 配置文件读入 Reader
    24. //            Reader reader = Resources.getResourceAsReader("mybatis-config.xml");
    25.             再通过 SqlSessionFactoryBuilder 建造类使用 Reader 创建 SqlSessionFactory工厂对象。
    26.             在创建 SqlSessionFactory 对象的过程中
    27.             首先解 mybatis-config.xml 配置文件，读取配置文件中的 mappers 配置后会读取全部的 Mapper xml 进行具体方法的解析，
    28.             在这些解析完成后， SqlSessionFactory 就包含了所有的属性配置和执行 SQL 的信息。
    29. //            sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
    30.             使用时通过 SqlSessionFactory 工厂对象获取 splSession
    31. //            reader.close();
    32. //        } catch (IOException ignore) {
    33. //            ignore.printStackTrace();
    34. //        }
    35. //    }
    36. //
    37. //    private void printCountryList(List<Country> countryList) {
    38. //        for (Country country : countryList) {
    39. //            System.out.printf("%-4d%4s%4s\n", country.getId(), country.getCountryname(), country.getCountrycode());
    40. //        }
    41. //    }
    42.  
    43.     @Test
    44.     public void testSelectByid() {
    45.         SqlSession sqlSession = getSqlSession();
    46.         try {
    47.             UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
    48.             SysUser user = userMapper.selectById((long) 1);
    49.             Assert.assertNotNull(user);
    50.             Assert.assertEquals("admin", user.getUserName());
    51.         } finally {
    52.             sqlSession.close();
    53.         }
    54.     }
    55.  
    56.     @Test
    57.     public void testSelectAll() {
    58.         SqlSession sqlSession = getSqlSession();
    59.         try {
    60.             UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
    61.             List<SysUser> userList = userMapper.selectAll();
    62.             Assert.assertNotNull(userList);
    63.             Assert.assertTrue(userList.size() > 0);
    64.         } finally {
    65.             sqlSession.close();
    66.         }
    67.     }
    68. }

    8.运行结果

    9.总结

    （1）mapper接口存放在java下的mapper包里，mapper.xml存放在资源包下面！

    namespace的值是对应的mapper接口的全限定名称

     

    （2）实体类用驼峰命名法，sql 里的映射

    1.用别名法映射

    2.自动映射

    配置：

     3.使用 resultMap

     

     

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  • 原文地址：https://blog.csdn.net/H215919719/article/details/128116674