Java EE 进阶：MyBatis案例练习

blammmp2025-03-29 11:31

表白墙

首先我们先准备一下数据库的数据

创建一个信息表

sql 复制代码 
DROP TABLE IF EXISTS message_info;
 CREATE TABLE `message_info` (
 `id` INT ( 11 ) NOT NULL AUTO_INCREMENT,
 `from` VARCHAR ( 127 ) NOT NULL,
 `to` VARCHAR ( 127 ) NOT NULL,
 `message` VARCHAR ( 256 ) NOT NULL,
 `delete_flag` TINYINT ( 4 ) DEFAULT 0 COMMENT
 `create_time` DATETIME DEFAULT now(),
 `update_time` DATETIME DEFAULT now() ON UPDATE now(),
 PRIMARY KEY ( `id` ) 
) ENGINE = INNODB DEFAULT CHARSET = utf8mb4;

引⼊MyBatis和MySQL驱动依赖

sql 复制代码 
<dependency>
 <groupId>org.mybatis.spring.boot</groupId>
 <artifactId>mybatis-spring-boot-starter</artifactId>
 <version>3.0.3</version>
 </dependency>
 <dependency>
 <groupId>com.mysql</groupId>
 <artifactId>mysql-connector-j</artifactId>
 <scope>runtime</scope>
 </dependency>

配置yml文件

sql 复制代码 
spring:
  application:
    name: springboot-demo
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/mybatis_test?characterEncoding=utf8&useSSL=false
    username: root
    password: 123456
    driver-class-name: com.mysql.cj.jdbc.Driver
mybatis:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
    map-underscore-to-camel-case: true

先创建实体类

java 复制代码 
@Data
public class MessageInfo {
    private Integer id;
    private String from;
    private String to;
    private String message;
    private Integer deleteFlag;
    private Date creatTime;
    private Date updateTime;
}

创建MessageMapper

java 复制代码 
@Mapper
public interface MessageMapper {

    @Select("SELECT `id`, `from`, `to`, `message` FROM message_info WHERE delete_flag = 0")
    List<MessageInfo> findMessage();

    @Insert("insert into message_info (`from`,`to`,message) values (#{from},#{to},#{message})")
    Integer addMessage(MessageInfo messageInfo);
}

创建MessageService

java 复制代码 
@Service
public class MessageService {



    @Autowired
    private MessageMapper messageMapper;

    private MessageInfo messageInfo;


    public Integer insertMessage(MessageInfo messageInfo) {
       return messageMapper.addMessage(messageInfo);
    }

    public List<MessageInfo> queryMessage() {
        return messageMapper.findMessage();
    }
}

测试

图书管理系统

准备数据库

sql 复制代码 
DROP DATABASE IF EXISTS book_test;
 CREATE DATABASE book_test DEFAULT CHARACTER SET utf8mb4;-- 
⽤⼾表
 
DROP TABLE IF EXISTS user_info;
 CREATE TABLE user_info (
 `id` INT NOT NULL AUTO_INCREMENT,
 `user_name` VARCHAR ( 128 ) NOT NULL,
 `password` VARCHAR ( 128 ) NOT NULL,
 `delete_flag` TINYINT ( 4 ) NULL DEFAULT 0,
 `create_time` DATETIME DEFAULT now(),
 `update_time` DATETIME DEFAULT now() ON UPDATE now(),
PRIMARY KEY ( `id` ),
 UNIQUE INDEX `user_name_UNIQUE` ( `user_name` ASC )) ENGINE = INNODB DEFAULT 
CHARACTER 
SET = utf8mb4 COMMENT = '⽤⼾表';
sql 复制代码 
DROP TABLE IF EXISTS book_info;
 CREATE TABLE `book_info` (
 `id` INT ( 11 ) NOT NULL AUTO_INCREMENT,
 `book_name` VARCHAR ( 127 ) NOT NULL,
 `author` VARCHAR ( 127 ) NOT NULL,
 `count` INT ( 11 ) NOT NULL,
 `price` DECIMAL (7,2 ) NOT NULL,
 `publish` VARCHAR ( 256 ) NOT NULL,
 `status` TINYINT ( 4 ) DEFAULT 1 COMMENT '0⽆效, 1正常, 2不允许借阅',
 `create_time` DATETIME DEFAULT now(),
 `update_time` DATETIME DEFAULT now() ON UPDATE now(),
 PRIMARY KEY ( `id` ) 
) ENGINE = INNODB DEFAULT CHARSET = utf8mb4;-- 
初始化数据
 
INSERT INTO user_info ( user_name, PASSWORD ) VALUES ( "admin", "admin" );
 INSERT INTO user_info ( user_name, PASSWORD ) VALUES ( "zhangsan", "123456" );
INSERT INTO book_info (id, book_name, author, count, price, publish, status, create_time, update_time) VALUES
(6, '解忧杂货店', '东野圭吾', 20, 45.50, '南海出版公司', 1, '2025-03-22 13:00:00', '2025-03-22 13:00:00'),
(7, '百年孤独', '加西亚·马尔克斯', 13, 88.00, '上海译文出版社', 1, '2025-03-22 13:05:00', '2025-03-22 13:05:00'),
(8, '追风筝的人', '卡勒德·胡赛尼', 25, 39.80, '上海人民出版社', 1, '2025-03-22 13:10:00', '2025-03-22 13:10:00'),
(9, '嫌疑人X的献身', '东野圭吾', 18, 42.00, '人民文学出版社', 1, '2025-03-22 13:15:00', '2025-03-22 13:15:00'),
(10, '围城', '钱钟书', 15, 36.00, '人民文学出版社', 1, '2025-03-22 13:20:00', '2025-03-22 13:20:00'),
(11, '牧羊少年奇幻之旅', '保罗·柯艾略', 12, 29.90, '作家出版社', 1, '2025-03-22 13:25:00', '2025-03-22 13:25:00'),
(12, '红楼梦', '曹雪芹', 30, 59.00, '中华书局', 1, '2025-03-22 13:30:00', '2025-03-22 13:30:00'),
(13, '西游记', '吴承恩', 28, 48.00, '人民文学出版社', 1, '2025-03-22 13:35:00', '2025-03-22 13:35:00'),
(14, '水浒传', '施耐庵', 22, 46.50, '人民文学出版社', 1, '2025-03-22 13:40:00', '2025-03-22 13:40:00'),
(15, '三国演义', '罗贯中', 27, 49.00, '人民文学出版社', 1, '2025-03-22 13:45:00', '2025-03-22 13:45:00'),
(16, '小王子', '圣埃克苏佩里', 17, 25.00, '新星出版社', 1, '2025-03-22 13:50:00', '2025-03-22 13:50:00'),
(17, '白夜行', '东野圭吾', 19, 55.00, '南海出版公司', 1, '2025-03-22 13:55:00', '2025-03-22 13:55:00'),
(18, '人类简史', '尤瓦尔·赫拉利', 14, 89.00, '中信出版社', 1, '2025-03-22 14:00:00', '2025-03-22 14:00:00'),
(19, '未来简史', '尤瓦尔·赫拉利', 10, 92.00, '中信出版社', 1, '2025-03-22 14:05:00', '2025-03-22 14:05:00'),
(20, '我们仨', '杨绛', 8, 28.00, '生活·读书·新知三联书店', 1, '2025-03-22 14:10:00', '2025-03-22 14:10:00'),
(21, '霍乱时期的爱情', '加西亚·马尔克斯', 9, 75.00, '上海译文出版社', 1, '2025-03-22 14:15:00', '2025-03-22 14:15:00'),
(22, '目送', '龙应台', 11, 34.50, '广西师范大学出版社', 1, '2025-03-22 14:20:00', '2025-03-22 14:20:00'),
(23, '文化苦旅', '余秋雨', 16, 32.00, '中华书局', 1, '2025-03-22 14:25:00', '2025-03-22 14:25:00'),
(24, '长安的荔枝', '马伯庸', 21, 40.00, '湖南文艺出版社', 1, '2025-03-22 14:30:00', '2025-03-22 14:30:00'),
(25, '解密', '麦家', 13, 37.50, '作家出版社', 1, '2025-03-22 14:35:00', '2025-03-22 14:35:00');

引⼊MyBatis和MySQL驱动依赖

sql 复制代码 
<dependency>
 <groupId>org.mybatis.spring.boot</groupId>
 <artifactId>mybatis-spring-boot-starter</artifactId>
 <version>3.0.3</version>
 </dependency>
 <dependency>
 <groupId>com.mysql</groupId>
<artifactId>mysql-connector-j</artifactId>
 <scope>runtime</scope>
 </dependency>

配置yml文件

sql 复制代码 
spring:
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/book_test?characterEncoding=utf8&useSSL=false&allowPublicKeyRetrieval=true
    username: root
    password: 123456
    driver-class-name: com.mysql.cj.jdbc.Driver

mybatis:
  configuration:
    map-underscore-to-camel-case: true
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
  mapper-locations: classpath:mapper/**.xml
logging:
  file:
    name: spring-book.log

UserInfo

java 复制代码 
@Data
public class UserInfo {
    private Integer id;
    private String userName;
    private String password;
    private Integer deleteFlag;
    private Data createTime;
    private Data updateTime;

}

BookInfo

java 复制代码 
@Data
public class BookInfo {
    private Integer Id;
    private String bookName;
    private String author;
    private Integer count;
    private Integer price;
    private String publish;
    private Integer status;
    private String statusCN;
    private Date createTime;
    private Date updateTime;
}

PageResult

java 复制代码 
@AllArgsConstructor
@NoArgsConstructor
@Data
public class PageResult<T> {
    private List<T> records;
    private int total;
    private PageRequest pageRequest;



    public PageResult(int total,List<T> records,PageRequest pageRequest) {
        this.records = records;
        this.total = total;
    }
}

PageRequest

java 复制代码 
@Data
public class PageRequest {
    private Integer currentPage=1;
    private Integer pageSize=10;
    private Integer offset;

    public Integer getOffset() {
        return (currentPage-1)*pageSize;
    }
}

Result

java 复制代码 
@Data
public class Result<T>  {
    private ResultCodeEnum code;
    private String errMes;
    private T data;


    public static <T> Result success(T data){
        Result result=new Result();
        result.setCode(ResultCodeEnum.SUCCESS);
        result.setErrMes("");
        result.setData(data);
        return result;
    }

    public static <T> Result fail(String errMes){
        Result result=new Result();
        result.setCode(ResultCodeEnum.UNLOGIN);
        result.setErrMes(errMes);
        result.setData(null);
        return result;
    }

    public static <T> Result fail(String errMes,T data){
        Result result=new Result();
        result.setCode(ResultCodeEnum.FAIL);
        result.setErrMes(errMes);
        result.setData(data);
        return result;
    }

    public static <T> Result unLogin(){
        Result result=new Result();
        result.setCode(ResultCodeEnum.UNLOGIN);
        result.setErrMes("登录失败");
        return result;
    }
}

UserController

java 复制代码 
@RequestMapping("/user")
@RestController
public class userController {

    @Autowired
    private UserService userService;

    @RequestMapping("/login")
    public boolean login(String name, String password, HttpSession session){

        if(!StringUtils.hasLength(name) || !StringUtils.hasLength(password)){
            return false;
        }
        UserInfo userInfo=userService.queryPasswordByUsername(name);
        if (userInfo==null){
            return false;
        }
        if(password.equals(userInfo.getPassword())){
            session.setAttribute(Constants.SESSION_USER_KEY,userInfo);
            return true;
        }

        return false;
    }
}

BookController

java 复制代码 
@RestController
@RequestMapping("/book")
public class bookController {

    private final BookService bookService;

    public bookController(BookService bookService) {
        this.bookService = bookService;
    }

    @RequestMapping("/getListByPage")
    public Result<PageResult<BookInfo>> getList(PageRequest pageRequest, HttpSession session){
        if(session.getAttribute(Constants.SESSION_USER_KEY)==null){
            return Result.unLogin();
        }
        UserInfo userinfo =(UserInfo) session.getAttribute(Constants.SESSION_USER_KEY);
        if(userinfo==null && userinfo.getId()<=0){
            return Result.unLogin();
        }
        PageResult<BookInfo> bookInfoPageResult = bookService.pageResult(pageRequest);
        return Result.success(bookInfoPageResult);


    }

    @RequestMapping("/addBook")
    public String addBook(@RequestBody BookInfo bookInfo){
        if (!StringUtils.hasLength(bookInfo.getBookName()) ||
                !StringUtils.hasLength(bookInfo.getAuthor()) ||
                bookInfo.getCount()==null ||
                bookInfo.getPrice()==null ||
                !StringUtils.hasLength(bookInfo.getPublish()) ||
                bookInfo.getStatus()==null
        ){
            return "输入不合法";
        }
        try {
            bookService.addBook(bookInfo);
            return "添加成功";
        } catch (Exception e){
            return "添加失败";
        }
    }

    @RequestMapping("/queryBookId")
    public BookInfo queryBookId(@RequestParam("bookId") Integer bookId){
        return bookService.queryBookId(bookId);
    }

    @RequestMapping ("/updateBook")
    public String updateBook(@RequestBody BookInfo bookInfo){
        bookService.update(bookInfo);
        return "更新成功";
    }

    @RequestMapping ("/deleteBook")
    public String deleteBook(@RequestBody Integer bookId){
        BookInfo bookInfo=new BookInfo();
        bookInfo.setId(bookId);
        bookInfo.setStatus(BookStatus.DELETED.getCode());
        bookService.update(bookInfo);
        return "删除成功";
    }
    @RequestMapping("batchDelete")
    public boolean batchDelete(@RequestBody List<Integer> ids){
        bookService.batchDelete(ids);
        return true;
    }
}

UserMapper

java 复制代码 
@Mapper
public interface UserMapper {

    @Select("select id, user_name,`password`, delete_flag, create_time,update_time from user_info where delete_flag=0 and user_name=#{name}")
    UserInfo queryPasswordByUsername(String name);
}

BookMapper

java 复制代码 
@Mapper
public interface BookMapper {

    @Insert("insert into book_info (book_name,author,count,price,publish,status) " +
            "values (#{bookName},#{author},#{count},#{price},#{publish},#{status})")
    void insertBook(BookInfo bookInfo);

    @Select("select * from book_info where status!=0 order by id asc limit #{offset},#{pageSize}")
    List<BookInfo> selectByPage(PageRequest pageRequest);

    @Select("select count(1) from book_info where status !=0")
    Integer count();

    @Select("select * from book_info where status!=0 and id=#{id}")
    BookInfo selectById(Integer id);


    Integer updateBook(BookInfo bookInfo);

    Integer batchDelete(List<Integer> ids);
}

UserService

java 复制代码 
@Service
public class UserService {

    @Autowired
    private UserMapper userMapper;


    public UserInfo queryPasswordByUsername(String name) {
        return userMapper.queryPasswordByUsername(name);
    }
}

BookService

java 复制代码 
@Service
public class BookService {
    //bookDao是数据库访问中的一个对象，现在我们对status这个对象进行修改
    @Autowired
    private BookMapper bookMapper;

    public void addBook(BookInfo bookInfo) {
        bookMapper.insertBook(bookInfo);
    }

    public PageResult<BookInfo> pageResult(PageRequest pageRequest){
        int count=bookMapper.count();
        List<BookInfo> bookInfos = bookMapper.selectByPage(pageRequest);
        for (BookInfo bookInfo:bookInfos) {
            bookInfo.setStatusCN(BookStatus.getCodeByName(bookInfo.getStatus()).getName());
        }
        return new PageResult<>(count,bookInfos,pageRequest);

    }


    public BookInfo queryBookId(Integer id) {
        return bookMapper.selectById(id);

    }

    public void update(BookInfo bookInfo) {
        bookMapper.updateBook(bookInfo);
    }

    public  Integer batchDelete(List<Integer> ids) {
        return bookMapper.batchDelete(ids);
    }
}

BookStatus

java 复制代码 
@Getter
public enum BookStatus {
    DELETED(0,"无效"),
    NORMAL(1,"可借阅"),
    FORBIDDEN(2,"不可借阅");
    private Integer code;
    private String name;

    BookStatus(Integer code, String name) {
        this.code = code;
        this.name = name;
    }

    public static BookStatus getCodeByName(Integer code){
        return switch (code) {
            case 0 -> DELETED;
            case 1 -> NORMAL;
            case 2 -> FORBIDDEN;
            default -> null;
        };
    }

    @Override
    public String toString() {
        return "BookStatus{" +
                "code=" + code +
                ", name='" + name + '\'' +
                '}';
    }
}

ResultCodeEnum

java 复制代码 
public enum ResultCodeEnum {
    UNLOGIN(-1),
    SUCCESS(200),
    FAIL(-2);

    private int code;

    ResultCodeEnum(int code){
        this.code=code;
    }
}

constants

java 复制代码 
public class Constants {
    public static final String SESSION_USER_KEY="session_user_info";
}

希望能对大家有所帮助！！！

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