Mybatis generator 1.4.x 入门教程--转载

Mybatis generator 1.4.x 入门教程

一、前言

​ 最近因为公司开了新的项目，所以在构建骨架的时候发现mybatis最新的版本已经更新到了1.4.0了,尝试了一下，比起之前的mybatis版本，有了更好的优化，用上了lamada表达式，还支持动态sql查询，所以在这里安利一波,因为之前我用的Laravel ORM,所以比较习惯使用这种lamada表达式来查询，可能之前用习惯了以前的查询方式的

二、官方文档地址

官方文档地址

三、集成 mybatis Generator 1.4.0

pom文件

代码语言：javascript复制

  ...
  
  
  
    org.mybatis.dynamic-sql
    mybatis-dynamic-sql
    1.1.4
  
     




...

  
    org.mybatis.generator
    mybatis-generator-maven-plugin
    1.4.0
    
    
    
    
  src/main/resources/mybatis/configuration.xml
    true
    true

配置文件 mybatis configuration.xml

代码语言：javascript复制

配置属性文件 db.properties

代码语言：javascript复制

jdbc.jar.path=/Users/xxx/.m2/repository/mysql/mysql-connector-java/8.0.17/mysql-connector-java-8.0.17.jar
jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://xxx:xxx:xxx:xxx:port/dbname?characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull&verifyServerCertificate=false
jdbc.username=username
jdbc.password=password
...

四、执行generator生成 dao类和mapper接口

• 生成dao类中每个属性会自动加上@Generated

生成的dao类

• 生成的mapper接口类，会自动生成Mapper和DynamicSqlSupport

五、使用举例

• Dao实例

代码语言：javascript复制

import java.io.Serializable;
import java.util.Date;
import javax.annotation.Generated;
public class Teacher implements Serializable {
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    private Integer id;
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    private String teacherNumber;
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    private String teacherName;
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    private String telephone;
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    private String email;
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    private String password;
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    private Boolean deleted;
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    private Date createdTime;
    @Generated("org.mybatis.gener"  
            "ator.api.MyBatisGenerator")
    private Date updatedTime;
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    private static final long serialVersionUID = 1L;
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    public Integer getId() {
        return id;
    }
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    public void setId(Integer id) {
        this.id = id;
    }
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    public String getTeacherNumber() {
        return teacherNumber;
    }
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    public void setTeacherNumber(String teacherNumber) {
        this.teacherNumber = teacherNumber == null ? null : teacherNumber.trim();
    }
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    public String getTeacherName() {
        return teacherName;
    }
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    public void setTeacherName(String teacherName) {
        this.teacherName = teacherName == null ? null : teacherName.trim();
    }
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    public String getTelephone() {
        return telephone;
    }
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    public void setTelephone(String telephone) {
        this.telephone = telephone == null ? null : telephone.trim();
    }
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    public String getEmail() {
        return email;
    }
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    public void setEmail(String email) {
        this.email = email == null ? null : email.trim();
    }
    ...
}  

5.1 查找

源码

代码语言：javascript复制

// 根据provider查询多个记录
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    @SelectProvider(type=SqlProviderAdapter.class, method="select")
    @ResultMap("TeacherResult")
    Optional selectOne(SelectStatementProvider selectStatement);
        
// 根据provider查询多个记录
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    @SelectProvider(type=SqlProviderAdapter.class, method="select")
    @Results(id="TeacherResult", value = {
        @Result(column="id", property="id", jdbcType=JdbcType.INTEGER, id=true),
        @Result(column="teacher_number", property="teacherNumber", jdbcType=JdbcType.VARCHAR),
        @Result(column="teacher_name", property="teacherName", jdbcType=JdbcType.VARCHAR),
        @Result(column="telephone", property="telephone", jdbcType=JdbcType.VARCHAR),
        @Result(column="email", property="email", jdbcType=JdbcType.VARCHAR),
        @Result(column="password", property="password", jdbcType=JdbcType.VARCHAR),
        @Result(column="deleted", property="deleted", jdbcType=JdbcType.BIT),
        @Result(column="created_time", property="createdTime", jdbcType=JdbcType.TIMESTAMP),
        @Result(column="updated_time", property="updatedTime", jdbcType=JdbcType.TIMESTAMP)
    })
    List selectMany(SelectStatementProvider selectStatement);

// 根据dsl 查询单个记录
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    default Optional selectOne(SelectDSLCompleter completer) {
        return MyBatis3Utils.selectOne(this::selectOne, selectList, teacher, completer);
    }
// 根据dsl 查询多个记录
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    default List select(SelectDSLCompleter completer) {
        return MyBatis3Utils.selectList(this::selectMany, selectList, teacher, completer);
    }

    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    default List selectDistinct(SelectDSLCompleter completer) {
        return MyBatis3Utils.selectDistinct(this::selectMany, selectList, teacher, completer);
    }
// 根据主键查询记录
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    default Optional selectByPrimaryKey(Integer id_) {
        return selectOne(c ->
            c.where(id, isEqualTo(id_))
        );
    }

实例

代码语言：javascript复制

    // 基本条件查询
 @Override
    public Teacher findById(Integer teacherId) {
        Optional teacher = teacherMapper.selectOne(c ->
                c.where(TeacherDynamicSqlSupport.deleted, isEqualTo(false))
                        .and(TeacherDynamicSqlSupport.id, isEqualTo(teacherId))
        );
        if (teacher.isPresent()){
            return teacher.get();
        }
        return null;
    }

// 条件查询分页
 @Override
    public List getListByPager(TeacherSearchModel model) {
      QueryExpressionWhereBuilder builder =        select(TeacherDynamicSqlSupport.teacher.allColumns())
        .from(TeacherDynamicSqlSupport.teacher)
        .where(TeacherDynamicSqlSupport.deleted, isEqualTo(false));
        if (!StringUtils.isEmpty(model.getNumberKeyWord()))
        {
            builder.and(TeacherDynamicSqlSupport.teacherNumber,isLike(model.getNumberKeyWord()));
        }
        if (!StringUtils.isEmpty(model.getNameKeyWord()))
        {
            builder.and(TeacherDynamicSqlSupport.teacherName,isLike(model.getNameKeyWord()));
        }
        builder.limit(model.getPageSize())
                .offset(((model.getPageNumber()-1)*model.getPageSize()));
        SelectStatementProvider provider = builder.build().render(RenderingStrategy.MYBATIS3);
        List teachers = teacherMapper.selectMany(provider);
        return teachers;
    }

5.2 更新

源码

代码语言：javascript复制

    // 根据provide更新
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    @UpdateProvider(type=SqlProviderAdapter.class, method="update")
    int update(UpdateStatementProvider updateStatement);

        @Generated("org.mybatis.generator.api.MyBatisGenerator")
    default int update(UpdateDSLCompleter completer) {
        return MyBatis3Utils.update(this::update, teacher, completer);
    }

    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    static UpdateDSL updateAllColumns(Teacher record, UpdateDSL dsl) {
        return dsl.set(id).equalTo(record::getId)
                .set(teacherNumber).equalTo(record::getTeacherNumber)
                .set(teacherName).equalTo(record::getTeacherName)
                .set(telephone).equalTo(record::getTelephone)
                .set(email).equalTo(record::getEmail)
                .set(password).equalTo(record::getPassword)
                .set(deleted).equalTo(record::getDeleted)
                .set(createdTime).equalTo(record::getCreatedTime)
                .set(updatedTime).equalTo(record::getUpdatedTime);
    }

    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    static UpdateDSL updateSelectiveColumns(Teacher record, UpdateDSL dsl) {
        return dsl.set(id).equalToWhenPresent(record::getId)
                .set(teacherNumber).equalToWhenPresent(record::getTeacherNumber)
                .set(teacherName).equalToWhenPresent(record::getTeacherName)
                .set(telephone).equalToWhenPresent(record::getTelephone)
                .set(email).equalToWhenPresent(record::getEmail)
                .set(password).equalToWhenPresent(record::getPassword)
                .set(deleted).equalToWhenPresent(record::getDeleted)
                .set(createdTime).equalToWhenPresent(record::getCreatedTime)
                .set(updatedTime).equalToWhenPresent(record::getUpdatedTime);
    }
        // 通过主键更新数据
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    default int updateByPrimaryKey(Teacher record) {
        return update(c ->
            c.set(teacherNumber).equalTo(record::getTeacherNumber)
            .set(teacherName).equalTo(record::getTeacherName)
            .set(telephone).equalTo(record::getTelephone)
            .set(email).equalTo(record::getEmail)
            .set(password).equalTo(record::getPassword)
            .set(deleted).equalTo(record::getDeleted)
            .set(createdTime).equalTo(record::getCreatedTime)
            .set(updatedTime).equalTo(record::getUpdatedTime)
            .where(id, isEqualTo(record::getId))
        );
    }

        // 通过主键条件更新数据
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    default int updateByPrimaryKeySelective(Teacher record) {
        return update(c ->
            c.set(teacherNumber).equalToWhenPresent(record::getTeacherNumber)
            .set(teacherName).equalToWhenPresent(record::getTeacherName)
            .set(telephone).equalToWhenPresent(record::getTelephone)
            .set(email).equalToWhenPresent(record::getEmail)
            .set(password).equalToWhenPresent(record::getPassword)
            .set(deleted).equalToWhenPresent(record::getDeleted)
            .set(createdTime).equalToWhenPresent(record::getCreatedTime)
            .set(updatedTime).equalToWhenPresent(record::getUpdatedTime)
            .where(id, isEqualTo(record::getId))
        );
    }

实例

代码语言：javascript复制

  @Override
    public int update(Teacher teacher) {
        return teacherMapper.updateByPrimaryKeySelective(teacher);
    }

5.3 添加(插入)

源码

代码语言：javascript复制

    // 直接完整插入
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    @InsertProvider(type=SqlProviderAdapter.class, method="insert")
    int insert(InsertStatementProvider insertStatement);

    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    @InsertProvider(type=SqlProviderAdapter.class, method="insertMultiple")
    int insertMultiple(MultiRowInsertStatementProvider multipleInsertStatement);
    // 直接完整插入
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    default int insert(Teacher record) {
        return MyBatis3Utils.insert(this::insert, record, teacher, c ->
            c.map(id).toProperty("id")
            .map(teacherNumber).toProperty("teacherNumber")
            .map(teacherName).toProperty("teacherName")
            .map(telephone).toProperty("telephone")
            .map(email).toProperty("email")
            .map(password).toProperty("password")
            .map(deleted).toProperty("deleted")
            .map(createdTime).toProperty("createdTime")
            .map(updatedTime).toProperty("updatedTime")
        );
    }
        
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    default int insertMultiple(Collection records) {
        return MyBatis3Utils.insertMultiple(this::insertMultiple, records, teacher, c ->
            c.map(id).toProperty("id")
            .map(teacherNumber).toProperty("teacherNumber")
            .map(teacherName).toProperty("teacherName")
            .map(telephone).toProperty("telephone")
            .map(email).toProperty("email")
            .map(password).toProperty("password")
            .map(deleted).toProperty("deleted")
            .map(createdTime).toProperty("createdTime")
            .map(updatedTime).toProperty("updatedTime")
        );
    }
        // 条件部分插入
    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    default int insertSelective(Teacher record) {
        return MyBatis3Utils.insert(this::insert, record, teacher, c ->
            c.map(id).toPropertyWhenPresent("id", record::getId)
            .map(teacherNumber).toPropertyWhenPresent("teacherNumber", record::getTeacherNumber)
            .map(teacherName).toPropertyWhenPresent("teacherName", record::getTeacherName)
            .map(telephone).toPropertyWhenPresent("telephone", record::getTelephone)
            .map(email).toPropertyWhenPresent("email", record::getEmail)
            .map(password).toPropertyWhenPresent("password", record::getPassword)
            .map(deleted).toPropertyWhenPresent("deleted", record::getDeleted)
            .map(createdTime).toPropertyWhenPresent("createdTime", record::getCreatedTime)
            .map(updatedTime).toPropertyWhenPresent("updatedTime", record::getUpdatedTime)
        );
    }

实例

代码语言：javascript复制

        @Override
    public int create(Teacher teacher) {
        return teacherMapper.insertSelective(teacher);
    }

5.4 删除

源码

代码语言：javascript复制

    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    @DeleteProvider(type=SqlProviderAdapter.class, method="delete")
    int delete(DeleteStatementProvider deleteStatement);

    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    default int delete(DeleteDSLCompleter completer) {
        return MyBatis3Utils.deleteFrom(this::delete, teacher, completer);
    }

    @Generated("org.mybatis.generator.api.MyBatisGenerator")
    default int deleteByPrimaryKey(Integer id_) {
        return delete(c -> 
            c.where(id, isEqualTo(id_))
        );
    }

5.5 查询数量 Count

源码

代码语言：javascript复制

 @Generated("org.mybatis.generator.api.MyBatisGenerator")
    @SelectProvider(type=SqlProviderAdapter.class, method="select")
    long count(SelectStatementProvider selectStatement);

 @Generated("org.mybatis.generator.api.MyBatisGenerator")
    @SelectProvider(type=SqlProviderAdapter.class, method="select")
    long count(SelectStatementProvider selectStatement);
 @Generated("org.mybatis.generator.api.MyBatisGenerator")
    default long count(CountDSLCompleter completer) {
        return MyBatis3Utils.countFrom(this::count, teacher, completer);
    }

实例

代码语言：javascript复制

        // 这里比较坑的是select的参数是count，如果是其他的会报错
        @Override
    public long getCountByModel(TeacherSearchModel model) {
        QueryExpressionWhereBuilder builder = select(count()).
                                                        from(TeacherDynamicSqlSupport.teacher)
                                                    .where(TeacherDynamicSqlSupport.deleted, isEqualTo(false));
        if (!StringUtils.isEmpty(model.getNumberKeyWord()))
        {             builder.and(TeacherDynamicSqlSupport.teacherNumber,isLike(model.getNumberKeyWord()));
        }
        if (!StringUtils.isEmpty(model.getNameKeyWord()))
        {
            builder.and(TeacherDynamicSqlSupport.teacherName,isLike(model.getNameKeyWord()));
        }
        SelectStatementProvider provider = builder.build().render(RenderingStrategy.MYBATIS3);
        long count = teacherMapper.count(provider);
        return count;
    }

5.6 查询条件

方法	说明
isNull/isNotNull	是否为空/不为空
isEqualTo/isNotEqualTo	是否等于/不等于
isEqualToWhenPresent/isNotEqualToWhenPresent	当存在时是否(不)等于
isGreaterThan/isGreaterThanWhenPresent	大于
isGreaterThanOrEqualTo/isGreaterThanOrEqualToWhenPresent	大于等于
isLessThan/isLessThanWhenPresent/	小于
isLessThanOrEqualTo/isLessThanOrEqualToWhenPresent	小于等于
isIn/isNotIn	in操作
isInWhenPresent/isNotInWhenPresent	in操作
isBetween/isNotBetween	是否在区间
isBetweenWhenPresent/isNotBetweenWhenPresent	是否在区间
isLike/isNotLike	like(需要添加%)
isLikeWhenPresent/isNotLikeWhenPresent	like(需要添加%)
isTrue/isFalse	是否是true/false
isLikeCaseInsensitive/isLikeCaseInsensitiveWhenPresent	like(需要添加%)
isNotLikeCaseInsensitive/isNotLikeCaseInsensitiveWhenPresent	like(需要添加%)
isInCaseInsensitive/isInCaseInsensitiveWhenPresent	in操作
isNotInCaseInsensitive/isNotInCaseInsensitiveWhenPresent	in操作

六、自定义查询

6.1 自定义mapper接口查询

代码语言：javascript复制

@Generated(value = "org.mybatis.generator.api.MyBatisGenerator",comments = "Source Table: user")
    @SelectProvider(type = SqlProviderAdapter.class,method = "select")
    @Results(id="UserVOResult", value = {
        @Result(column="id", property="id", jdbcType= JdbcType.VARCHAR, id=true),
        @Result(column="user_name", property="userName", jdbcType=JdbcType.VARCHAR),
        @Result(column="gender", property="gender", jdbcType=JdbcType.BIT),
        @Result(column="avatar", property="avatar", jdbcType=JdbcType.VARCHAR),
        @Result(column="mobile", property="mobile", jdbcType=JdbcType.VARCHAR),
        @Result(column="email", property="email", jdbcType=JdbcType.VARCHAR),
        @Result(column="organization_name", property="organizationName", jdbcType=JdbcType.VARCHAR),
        @Result(column="real_name", property="realName", jdbcType=JdbcType.VARCHAR),
        @Result(column="main_organization", property="mainOrganization", jdbcType=JdbcType.INTEGER),
        @Result(column="organization", property="organization", jdbcType=JdbcType.VARCHAR),
        @Result(column="create_time", property="createTime", jdbcType=JdbcType.TIMESTAMP),
        @Result(column="update_time", property="updateTime", jdbcType=JdbcType.TIMESTAMP)
    })
    List selectManyJoin(SelectStatementProvider selectStatementProvider);

6.2 自定义sql解析器查询

代码语言：javascript复制

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.ibatis.mapping.SqlSource;
import org.apache.ibatis.scripting.LanguageDriver;
import org.apache.ibatis.scripting.xmltags.XMLLanguageDriver;
import org.apache.ibatis.session.Configuration;

/**
 * 解析sql语句该类主要用作select
 */
public class SimpleSelectInLangDriver extends XMLLanguageDriver implements LanguageDriver {

    private static final Pattern inPattern = Pattern.compile("\(#\{(\w )\}\)");

    @Override
    public SqlSource createSqlSource(Configuration configuration, String script, Class parameterType) {

        Matcher matcher = inPattern.matcher(script);
        if (matcher.find()) {
            script = matcher.replaceAll("#{_item}");
        }

        script = ""   script   "";
        return super.createSqlSource(configuration, script, parameterType);
    }
}

代码语言：javascript复制

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.ibatis.mapping.SqlSource;
import org.apache.ibatis.scripting.LanguageDriver;
import org.apache.ibatis.scripting.xmltags.XMLLanguageDriver;
import org.apache.ibatis.session.Configuration;

/**
 * 解析sql语句
 */
public class SimpleUpdateLangDriver extends XMLLanguageDriver implements LanguageDriver{

    private final Pattern inPattern = Pattern.compile("\(#\{(\w )\}\)");

    @Override
    public SqlSource createSqlSource(Configuration configuration, String script, Class parameterType) {
//        Matcher matcher = inPattern.matcher(script);
//        if (matcher.find()) {
//            StringBuilder sb = new StringBuilder();
//            sb.append("");
//
//            sb.append("   name = #{name},");
//            sb.append(" price = #{price},");


         /*   for (Field field : parameterType.getDeclaredFields()) {
                String tmp = "_column=#{_field},";
                sb.append(tmp.replaceAll("_field", field.getName()).replaceAll("_column",
                        CaseFormat.LOWER_CAMEL.to(CaseFormat.LOWER_UNDERSCORE, field.getName())));
            }*/

//            sb.deleteCharAt(sb.lastIndexOf(","));
//            sb.append("");

//            script = matcher.replaceAll(sb.toString());
//            script = ""   script   "";
//        }

        return super.createSqlSource(configuration, script, parameterType);
    }
}

代码语言：javascript复制

import cn.jhunicom.visitor.miniapp.model.entity.mysql.UserBaseEntity;
import cn.jhunicom.visitor.miniapp.utils.SimpleSelectInLangDriver;
import cn.jhunicom.visitor.miniapp.utils.SimpleUpdateLangDriver;
import org.apache.ibatis.annotations.Lang;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;

import java.util.List;

public interface UserBaseEntityMapperExt extends UserBaseEntityMapper {
  @Select("SELECT * FROM user_base")
  @Lang(SimpleSelectInLangDriver.class)
  List selectUserEntity();

  @Select("SELECT * FROM user_base  WHERE `name` NOT IN (SELECT name FROM user_base  WHERE id IN (#{idList}))")
  @Lang(SimpleSelectInLangDriver.class)
  List getUserByIdInBatch(@Param("idList") List idList);

  @Update("UPDATE user_base set name = #{name} WHERE id = #{id}")
  @Lang(SimpleUpdateLangDriver.class)
  void updateUsersById(UserBaseEntity userBaseEntity);
}

七、bug记录

7.1 in操作的坑

isIn/isNotIn/isInCaseInsensitive/isInCaseInsensitiveWhenPresent/isNotInCaseInsensitive/isNotInCaseInsensitiveWhenPresent 操作中，如果给的List(获取其他可迭代对象)为空的话，这个条件就不生效了。

• 例如你要进行如下操作

代码语言：javascript复制

select * from user where id in ("xxx","xxx")

• mybatis 中写法

代码语言：javascript复制

List userIds = ...
List users = userMapper.select(c -> c.where(UserDynamicSqlSupport.id, isIn(userIds)));

• bug

如果userIds 不为空(length = 0)的话，sql 语句是对的，如果userIds为空的话，sql语句就变成select * from user 了。÷

mybatis sql 官方文档 javascript 编程算法

0 人点赞