mybatis-plus updateById源码

1.版本 : mybatis-plus-core 3.5.1

2.入口:MybatisPlusAutoConfiguration类sqlSessionFactory中的factory.getObject()

3.注入AbstractSqlInjector类中的inspectInject方法中

@Override
    public void inspectInject(MapperBuilderAssistant builderAssistant, Class<?> mapperClass) {
        Class<?> modelClass = ReflectionKit.getSuperClassGenericType(mapperClass, Mapper.class, 0);
        if (modelClass != null) {
            String className = mapperClass.toString();
            Set<String> mapperRegistryCache = GlobalConfigUtils.getMapperRegistryCache(builderAssistant.getConfiguration());
            if (!mapperRegistryCache.contains(className)) {
                TableInfo tableInfo = TableInfoHelper.initTableInfo(builderAssistant, modelClass);
                List<AbstractMethod> methodList = this.getMethodList(mapperClass, tableInfo);
                if (CollectionUtils.isNotEmpty(methodList)) {
                    // 循环注入自定义方法
                    methodList.forEach(m -> m.inject(builderAssistant, mapperClass, modelClass, tableInfo));
                } else {
                    logger.debug(mapperClass.toString() + ", No effective injection method was found.");
                }
                mapperRegistryCache.add(className);
            }
        }
    }

主要是下面两段逻辑:

(1).List<AbstractMethod> methodList = this.getMethodList(mapperClass, tableInfo); 这里的DefaultSqlInjector增加所有的默认方法

@Override
    public List<AbstractMethod> getMethodList(Class<?> mapperClass, TableInfo tableInfo) {
        Stream.Builder<AbstractMethod> builder = Stream.<AbstractMethod>builder()
            .add(new Insert())
            .add(new Delete())
            .add(new DeleteByMap())
            .add(new Update())
            .add(new SelectByMap())
            .add(new SelectCount())
            .add(new SelectMaps())
            .add(new SelectMapsPage())
            .add(new SelectObjs())
            .add(new SelectList())
            .add(new SelectPage());
        if (tableInfo.havePK()) {
            builder.add(new DeleteById())
                .add(new DeleteBatchByIds())
                .add(new UpdateById())
                .add(new SelectById())
                .add(new SelectBatchByIds());
        } else {
            logger.warn(String.format("%s ,Not found @TableId annotation, Cannot use Mybatis-Plus 'xxById' Method.",
                tableInfo.getEntityType()));
        }
        return builder.build().collect(toList());
    }

(2).methodList.forEach(m -> m.inject(builderAssistant, mapperClass, modelClass, tableInfo));这里实现默认方法的sql(inject中的injectMappedStatement方法)

public void inject(MapperBuilderAssistant builderAssistant, Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) {
    this.configuration = builderAssistant.getConfiguration();
    this.builderAssistant = builderAssistant;
    this.languageDriver = configuration.getDefaultScriptingLanguageInstance();
    /* 注入自定义方法 */
    injectMappedStatement(mapperClass, modelClass, tableInfo);
}

4.UpdateById类实现AbstractMethod接口

public class UpdateById extends AbstractMethod {

    public UpdateById() {
        super(SqlMethod.UPDATE_BY_ID.getMethod());
    }

    /**
     * @since 3.5.0
     * @param name 方法名
     */
    public UpdateById(String name) {
        super(name);
    }

    @Override
    public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) {
        SqlMethod sqlMethod = SqlMethod.UPDATE_BY_ID;
        final String additional = optlockVersion(tableInfo) + tableInfo.getLogicDeleteSql(true, true);
        String sql = String.format(sqlMethod.getSql(), tableInfo.getTableName(),
            sqlSet(tableInfo.isWithLogicDelete(), false, tableInfo, false, ENTITY, ENTITY_DOT),
            tableInfo.getKeyColumn(), ENTITY_DOT + tableInfo.getKeyProperty(), additional);
        SqlSource sqlSource = languageDriver.createSqlSource(configuration, sql, modelClass);
        return addUpdateMappedStatement(mapperClass, modelClass, getMethod(sqlMethod), sqlSource);
    }
}

injectMappedStatement中生成全字段SQL脚本(

<script>

UPDATE xxxxx <set>

<if test="et['changeType'] != null">change_type=#{et.changeType},</if>

<if test="et['creator'] != null">creator=#{et.creator},</if>

<if test="et['createTime'] != null">create_time=#{et.createTime},</if>

update_time=now(),

</set> WHERE id=#{et.id} AND is_delete=0

</script>)

会被封装为 MyBatis 的 MappedStatement，并注册到 MyBatis 的 Configuration 中，

然后通过mapper代理调用