mybatis plus自定义的mapper如何动态切换数据源

Posted 2023-05-11

参考技术A 在配置文件更换数据库路径即可

Mybatis-plus 自定义SQL注入器查询@TableLogic 逻辑删除后的数据

目录

1  需求

2  解决方案

3  方案：

3.1  方案1，继承 AbstractMethod拼接SQL语句

3.2. 方案2，继承 AbstractMethod拼接SQL语句

4.  自定义SQL注入器，注册上述自定义的方法

5.  自定义基础mapper，声明注册的方法

6. 使用声明的方法

6.1  业务mapper继承自定义的CustomBaseMapper

6.2 调用方法selectIgnoreLogicDelete

6.3 调用方法selectIgnoreLogicDeleteByMap

---

1  需求

Mybatis-plus使用@TableLogic注解进行逻辑删除数据后，在某些场景下，又需要查询该数据时，又不想写SQL。

2  解决方案

自定义Mybatis-plus的SQL注入器一劳永逸的解决该问题

3  方案：

3.1  方案1，继承 AbstractMethod拼接SQL语句

public class SelectIgnoreLogicDeleteByMap extends AbstractMethod 

    @Override
    public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) 

        String sqlBase= "<script>SELECT %s FROM %s %s\\n</script>";
        String sqlScript = this.sqlWhereByMap(tableInfo);
        String sql = String.format(sqlBase, this.sqlSelectColumns(tableInfo, false), tableInfo.getTableName(), sqlScript);
        SqlSource sqlSource = this.languageDriver.createSqlSource(this.configuration, sql, Map.class);
        return this.addSelectMappedStatementForTable(mapperClass, "selectIgnoreLogicDeleteByMap", sqlSource, tableInfo);
    

    /**
     * 拼接where条件根据map参数
     *
     * @param table 表
     * @return sql
     */
    protected String sqlWhereByMap(TableInfo table) 
        String sqlScript;
        sqlScript = SqlScriptUtils.convertChoose("v == null", " $k IS NULL ", " $k = #v ");
        sqlScript = SqlScriptUtils.convertForeach(sqlScript, "cm", "k", "v", "AND");
        sqlScript = SqlScriptUtils.convertWhere(sqlScript);
        sqlScript = SqlScriptUtils.convertIf(sqlScript, String.format("%s != null and !%s", "cm", "cm.isEmpty"), true);
        return sqlScript;
    

3.2. 方案2，继承 AbstractMethod拼接SQL语句

public class SelectIgnoreLogicDelete extends AbstractMethod 

    @Override
    public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) 

        String sqlBase = "<script>%s SELECT %s FROM %s %s %s %s\\n</script>";

        String sql = String.format(sqlBase, this.sqlFirst(), this.sqlSelectColumns(tableInfo, true), tableInfo.getTableName(), this.sqlWhereEntityWrapper(true, tableInfo), this.sqlOrderBy(tableInfo), this.sqlComment());
        SqlSource sqlSource = this.languageDriver.createSqlSource(this.configuration, sql, modelClass);
        return this.addSelectMappedStatementForTable(mapperClass, "selectIgnoreLogicDelete", sqlSource, tableInfo);
    

    /**
     * 拼接where条件
     *
     * @param newLine 新行
     * @param table   表
     * @return sql
     */
    protected String sqlWhereEntityWrapper(boolean newLine, TableInfo table) 
        String sqlScript = table.getAllSqlWhere(false, true, "ew.entity.");
        sqlScript = SqlScriptUtils.convertIf(sqlScript, String.format("%s != null", "ew.entity"), true);
        sqlScript = sqlScript + "\\n";
        sqlScript = sqlScript + SqlScriptUtils.convertIf(String.format(SqlScriptUtils.convertIf(" AND", String.format("%s and %s", "ew.nonEmptyOfEntity", "ew.nonEmptyOfNormal"), false) + " $%s", "ew.sqlSegment"), String.format("%s != null and %s != '' and %s", "ew.sqlSegment", "ew.sqlSegment", "ew.nonEmptyOfWhere"), true);
        sqlScript = SqlScriptUtils.convertWhere(sqlScript) + "\\n";
        sqlScript = sqlScript + SqlScriptUtils.convertIf(String.format(" $%s", "ew.sqlSegment"), String.format("%s != null and %s != '' and %s", "ew.sqlSegment", "ew.sqlSegment", "ew.emptyOfWhere"), true);
        sqlScript = SqlScriptUtils.convertIf(sqlScript, String.format("%s != null", "ew"), true);
        return newLine ? "\\n" + sqlScript : sqlScript;
    

4.  自定义SQL注入器，注册上述自定义的方法

public class CustomSqlInjector extends DefaultSqlInjector 

    @Override
    public List<AbstractMethod> getMethodList(Class<?> mapperClass, TableInfo tableInfo) 
        List<AbstractMethod> methodList = super.getMethodList(mapperClass, tableInfo);
        methodList.add(new SelectIgnoreLogicDeleteByMap());
        methodList.add(new SelectIgnoreLogicDelete());
        return methodList;
    

5.  自定义基础mapper，声明注册的方法

public interface CustomBaseMapper<T> extends BaseMapper<T> 

    /**
     * 根据map条件查询数据，并忽略逻辑删除
     *
     * @param columnMap 查询条件
     * @return 结果信息
     */
    List<T> selectIgnoreLogicDeleteByMap(@Param("cm") Map<String, Object> columnMap);

    /**
     * 根据条件查询数据，并忽略逻辑删除
     *
     * @param queryWrapper 查询条件
     * @return 结果信息
     */
    List<T> selectIgnoreLogicDelete(@Param("ew") Wrapper<T> queryWrapper);

6. 使用声明的方法

6.1  业务mapper继承自定义的CustomBaseMapper

@Mapper
public interface UserMapper extends CustomBaseMapper<User> 

6.2 调用方法selectIgnoreLogicDelete

    @Override
    public List<User> getIgnoreDeleteById(Long userId) 
        LambdaQueryWrapper<User> queryWrapper = new LambdaQueryWrapper<>();
        queryWrapper.eq(User::getId,userId);
        return this.baseMapper.selectIgnoreLogicDelete(queryWrapper);
    

6.3 调用方法selectIgnoreLogicDeleteByMap

    @Override
    public List<User> getIgnoreDeleteById(Long userId) 
		Map<String, Object> columnMap = new HashMap<>(2);
        columnMap.put("id", userId);
        return this.baseMapper.selectIgnoreLogicDeleteByMap(columnMap);