Mybatis generator 1.4.x 入门教程--转载

allsmallpig

发布于 2021-02-25 15:24:59

9790

发布于 2021-02-25 15:24:59

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

  ...
  
  
  
    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

配置属性文件 db.properties

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

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

// 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

    // 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

    // 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

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

5.3 添加(插入)

源码

    // 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

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

5.4 删除

源码

    @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

 @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

        // 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

@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

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);
    }
}

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);
    }
}

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

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

mybatis 中写法

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

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。÷

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Mybatis generator 1.4.x 入门教程--转载

Mybatis generator 1.4.x 入门教程--转载

Mybatis generator 1.4.x 入门教程

一、前言

二、官方文档地址

三、集成 mybatis Generator 1.4.0

pom文件

配置文件 mybatis configuration.xml

配置属性文件 db.properties

四、执行generator生成 dao类和mapper接口

五、使用举例

5.1 查找

5.2 更新

5.3 添加(插入)

5.4 删除

5.5 查询数量 Count

5.6 查询条件

六、自定义查询

6.1 自定义mapper接口查询

6.2 自定义sql解析器查询

七、bug记录

7.1 in操作的坑

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