MBP中yml属性注入及逻辑删除过程

作者: CalmHeart | 来源:发表于2021-12-08 10:39 被阅读0次

背景 : 参考这篇文章 https://www.cnblogs.com/54chensongxia/p/14247966.html 想做唯一索引并且使用MybatisPlus做逻辑删除保证数据正常插入
想采用的是下面一个解决方案
解决方案
在实现的过程碰到的问题做一下汇总 logic-delete-value: null
当前使用的mbp版本是3.3.1
yml

# mybatis-plus
#具体默认配置项参考com.baomidou.mybatisplus.autoconfigure.MybatisPlusProperties
mybatis-plus:
  #参考默认配置项 可以忽略
  mapper-locations: classpath*:/mapper/**/*.xml
  #具体默认配置项参考com.baomidou.mybatisplus.core.config.GlobalConfig
  global-config: 
    #具体默认配置项参考com.baomidou.mybatisplus.core.config.GlobalConfig.DbConfig
    db-config:
      # 默认配置是1 需要使用null覆盖
      logic-delete-value: null
      # 默认配置是0 可以忽略
      logic-not-delete-value: 0 
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

1. 注入

@Configuration
@ConditionalOnClass({SqlSessionFactory.class, SqlSessionFactoryBean.class})
@ConditionalOnSingleCandidate(DataSource.class)
@EnableConfigurationProperties(MybatisPlusProperties.class)
@AutoConfigureAfter({DataSourceAutoConfiguration.class, MybatisPlusLanguageDriverAutoConfiguration.class})
public class MybatisPlusAutoConfiguration implements InitializingBean

注入MybatisPlusProperties

@Data
@Accessors(chain = true)
@ConfigurationProperties(prefix = Constants.MYBATIS_PLUS) 注意这个前缀
public class MybatisPlusProperties

部分默认值

由此可见yml中的mapperLocations冗余

嵌套注入配置类

逻辑删除:

3.1 com.baomidou.mybatisplus.core.injector.AbstractSqlInjector#inspectInject

inspectInject
3.2 com.baomidou.mybatisplus.core.metadata.TableInfoHelper#initTableInfo

核心方法
3.3 com.baomidou.mybatisplus.core.metadata.TableInfoHelper#initTableFields

核心方法
3.4 com.baomidou.mybatisplus.core.metadata.TableFieldInfo#TableFieldInfo(com.baomidou.mybatisplus.core.config.GlobalConfig.DbConfig, com.baomidou.mybatisplus.core.metadata.TableInfo, java.lang.reflect.Field)

核心方法
3.5 com.baomidou.mybatisplus.core.metadata.TableFieldInfo#initLogicDelete

核心方法
3.6 上述3.3步骤中还有一个核心方法
com.baomidou.mybatisplus.core.metadata.TableInfo#setFieldList

核心方法

  void setFieldList(List<TableFieldInfo> fieldList) {
        this.fieldList = fieldList;
        fieldList.forEach(i -> {
            if (i.isLogicDelete()) {//核心方法
                this.logicDelete = true;
            }
            if (i.isWithInsertFill()) {
                this.withInsertFill = true;
            }
            if (i.isWithUpdateFill()) {
                this.withUpdateFill = true;
            }
            if (i.isVersion()) {
                this.withVersion = true;
                this.versionFieldInfo = i;
            }
        });
    }

3.7 com.baomidou.mybatisplus.core.metadata.TableFieldInfo#isLogicDelete

    /**
     * 是否启用了逻辑删除
     */
    public boolean isLogicDelete() {
        return StringUtils.isNotBlank(logicDeleteValue) && StringUtils.isNotBlank(logicNotDeleteValue);
    }

如果mybatis-plus.global-config.db-config.logic-delete-value:null 那么springboot注入得到的值是"" 需要研究下
参考SpringBoot yml配置null坑
所以这里判断不是逻辑删除所以后续走了物理删除

LogicDeleteByIdWithFill

debug截图

debug stack

解决方案1:

# mybatis-plus
#具体默认配置项参考com.baomidou.mybatisplus.autoconfigure.MybatisPlusProperties
mybatis-plus:
  #参考默认配置项 可以忽略
  mapper-locations: classpath*:/mapper/**/*.xml
  #具体默认配置项参考com.baomidou.mybatisplus.core.config.GlobalConfig
  global-config:
    #具体默认配置项参考com.baomidou.mybatisplus.core.config.GlobalConfig.DbConfig
    db-config:
      # 默认配置是1 需要使用null覆盖
      logic-delete-value: "null"
      # 默认配置是0 可以忽略
      logic-not-delete-value: 0
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

这样可以解决的原因需要参考mbp底层对于"null"的处理逻辑，代码片段如下:
com.baomidou.mybatisplus.core.metadata.TableInfo#formatLogicDeleteSql

/**
     * format logic delete SQL, can be overrided by subclass
     * github #1386
     *
     * @param isWhere true: logicDeleteValue, false: logicNotDeleteValue
     * @return sql
     */
    private String formatLogicDeleteSql(boolean isWhere) {
        final String value = isWhere ? logicDeleteFieldInfo.getLogicNotDeleteValue() : logicDeleteFieldInfo.getLogicDeleteValue();
        if (isWhere) {
            if (NULL.equalsIgnoreCase(value)) {
                return logicDeleteFieldInfo.getColumn() + " IS NULL";
            } else {
                return logicDeleteFieldInfo.getColumn() + EQUALS + String.format(logicDeleteFieldInfo.isCharSequence() ? "'%s'" : "%s", value);
            }
        }
        final String targetStr = logicDeleteFieldInfo.getColumn() + EQUALS;
        if (NULL.equalsIgnoreCase(value)) {
            return targetStr + NULL;
        } else {
            return targetStr + String.format(logicDeleteFieldInfo.isCharSequence() ? "'%s'" : "%s", value);
        }
    }

tips: String NULL = "null";

解决方案2:
拦截逻辑删除处理的语句：方式是重写SystemLogicDeleteById覆盖默认的LogicDeleteSqlInjector

/**
 * 根据 id 逻辑删除数据,并带字段填充功能
 * <p>注意入参是 entity !!! ,如果字段没有自动填充,就只是单纯的逻辑删除</p>
 * <p>
 * 自己的通用 mapper 如下使用:
 * <pre>
 * int deleteByIdWithFill(T entity);
 * </pre>
 * </p>
 *
 * @author miemie
 * @since 2018-11-09
 */
public class SystemLogicDeleteById extends AbstractMethod {

  @Override
  public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) {
    String sql;
    SqlMethod sqlMethod = SqlMethod.LOGIC_DELETE_BY_ID;
    if (tableInfo.isLogicDelete()) {
      List<TableFieldInfo> fieldInfos = tableInfo.getFieldList().stream()
          .filter(TableFieldInfo::isWithUpdateFill)
          .collect(toList());
      if (CollectionUtils.isNotEmpty(fieldInfos)) {
        String sqlSet = "SET " + fieldInfos.stream().map(i -> i.getSqlSet(EMPTY)).collect(joining(EMPTY))
            + tableInfo.getLogicDeleteSql(false, false);
        sql = String.format(sqlMethod.getSql(), tableInfo.getTableName(), sqlSet, tableInfo.getKeyColumn(),
            tableInfo.getKeyProperty(), tableInfo.getLogicDeleteSql(true, true));
      } else {
        sql = String.format(sqlMethod.getSql(), tableInfo.getTableName(), "SET deleted=null",
            tableInfo.getKeyColumn(), tableInfo.getKeyProperty(),
            tableInfo.getLogicDeleteSql(true, true));
      }
    } else {
      sqlMethod = SqlMethod.DELETE_BY_ID;
      sql = String.format(sqlMethod.getSql(), tableInfo.getTableName(), tableInfo.getKeyColumn(),
          tableInfo.getKeyProperty());
    }
    SqlSource sqlSource = languageDriver.createSqlSource(configuration, sql, modelClass);
    return addUpdateMappedStatement(mapperClass, modelClass, getMethod(sqlMethod), sqlSource);
  }

  @Override
  public String getMethod(SqlMethod sqlMethod) {
    // 自定义 mapper 方法名
    return "deleteByIdWithFill";
  }
}

@Configuration
@EnableTransactionManagement
@MapperScan(basePackages = {"com.compass.msg.**.mapper"})
public class MybatisPlusConfig {

  /**
   * mybatis-plus分页插件
   */
  @Bean
  public PaginationInterceptor paginationInterceptor() {
    PaginationInterceptor paginationInterceptor = new PaginationInterceptor();
    //开启 count 的 join 优化,只针对部分 left join
    paginationInterceptor.setCountSqlParser(new JsqlParserCountOptimize(true));
    return new PaginationInterceptor();
  }

  /**
   * 乐观锁mybatis插件
   */
  @Bean
  public OptimisticLockerInterceptor optimisticLockerInterceptor() {
    return new OptimisticLockerInterceptor();
  }

  /**
   * 逻辑删除sql注射器
   *
   * @return {@link LogicDeleteSqlInjector }
   * @author lvsheng
   * @date 2021/11/22 12:48
   */
  @Bean
  public LogicDeleteSqlInjector logicDeleteSqlInjector() {
    return new LogicDeleteSqlInjector();
  }


/**
 * 逻辑删除sql注射器
 *
 * @author lvsheng
 * @version 1.0.0
 * @date 2021/11/22 12:50
 * @see DefaultSqlInjector
 */
public class LogicDeleteSqlInjector extends DefaultSqlInjector {

  @Override
  public List<AbstractMethod> getMethodList(Class<?> mapperClass) {
    List<AbstractMethod> methodList = super.getMethodList(mapperClass);
    methodList.add(new SystemLogicDeleteById());
    return methodList;
  }
}

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