org.apache.ibatis.executor.keygen.SelectKeyGenerator Java Exaples

Source File: SimpleStatementHandler.java From mybatis with Apache License 2.0

6 votes

@Override
public int update(Statement statement) throws SQLException {
  String sql = boundSql.getSql();
  Object parameterObject = boundSql.getParameterObject();
  KeyGenerator keyGenerator = mappedStatement.getKeyGenerator();
  int rows;
  if (keyGenerator instanceof Jdbc3KeyGenerator) {
    statement.execute(sql, Statement.RETURN_GENERATED_KEYS);
    rows = statement.getUpdateCount();
    keyGenerator.processAfter(executor, mappedStatement, statement, parameterObject);
  } else if (keyGenerator instanceof SelectKeyGenerator) {
    statement.execute(sql);
    rows = statement.getUpdateCount();
    keyGenerator.processAfter(executor, mappedStatement, statement, parameterObject);
  } else {
    //如果没有keyGenerator,直接调用Statement.execute和Statement.getUpdateCount
    statement.execute(sql);
    rows = statement.getUpdateCount();
  }
  return rows;
}

Source File: RwRouteHandler.java From azeroth with Apache License 2.0

6 votes

@Override
public Object onInterceptor(Invocation invocation) throws Throwable {

    Object[] objects = invocation.getArgs();
    MappedStatement ms = (MappedStatement) objects[0];
    //已指定强制使用
    if (DataSourceContextHolder.get().isForceUseMaster()) {
        logger.debug("Method[{}] force use Master..", ms.getId());
        return null;
    }

    //读方法
    if (ms.getSqlCommandType().equals(SqlCommandType.SELECT)) {
        //!selectKey 为自增id查询主键(SELECT LAST_INSERT_ID() )方法，使用主库
        if (!ms.getId().contains(SelectKeyGenerator.SELECT_KEY_SUFFIX)) {
            DataSourceContextHolder.get().useSlave(true);
            logger.debug("Method[{} use Slave Strategy..", ms.getId());
        }
    } else {
        logger.debug("Method[{}] use Master Strategy..", ms.getId());
        DataSourceContextHolder.get().useSlave(false);
    }

    return null;
}

Source File: RwRouteHandler.java From jeesuite-libs with Apache License 2.0

6 votes

@Override
public Object onInterceptor(Invocation invocation) throws Throwable {
	
	Object[] objects = invocation.getArgs();
	MappedStatement ms = (MappedStatement) objects[0];
	//已指定强制使用
	if(MybatisRuntimeContext.isForceUseMaster()){
		logger.debug("Method[{}] force use Master..",ms.getId());
		return null;
	}
	
	//读方法
	if(ms.getSqlCommandType().equals(SqlCommandType.SELECT)){
		//!selectKey 为自增id查询主键(SELECT LAST_INSERT_ID() )方法，使用主库
		if(!ms.getId().contains(SelectKeyGenerator.SELECT_KEY_SUFFIX)){				
			MybatisRuntimeContext.useSlave(true);
			logger.debug("Method[{} use Slave Strategy..",ms.getId());
		}
	}else{
		logger.debug("Method[{}] use Master Strategy..",ms.getId());
		MybatisRuntimeContext.useSlave(false);
	}
	
	return null;
}

Source File: SimpleStatementHandler.java From mybaties with Apache License 2.0

6 votes

@Override
public int update(Statement statement) throws SQLException {
  String sql = boundSql.getSql();
  Object parameterObject = boundSql.getParameterObject();
  KeyGenerator keyGenerator = mappedStatement.getKeyGenerator();
  int rows;
  if (keyGenerator instanceof Jdbc3KeyGenerator) {
    statement.execute(sql, Statement.RETURN_GENERATED_KEYS);
    rows = statement.getUpdateCount();
    keyGenerator.processAfter(executor, mappedStatement, statement, parameterObject);
  } else if (keyGenerator instanceof SelectKeyGenerator) {
    statement.execute(sql);
    rows = statement.getUpdateCount();
    keyGenerator.processAfter(executor, mappedStatement, statement, parameterObject);
  } else {
    //如果没有keyGenerator,直接调用Statement.execute和Statement.getUpdateCount
    statement.execute(sql);
    rows = statement.getUpdateCount();
  }
  return rows;
}

Source File: ExecutorTestHelper.java From mybatis with Apache License 2.0

5 votes

public static MappedStatement prepareInsertAuthorMappedStatementWithBeforeAutoKey(final Configuration config) {
  final TypeHandlerRegistry registry = config.getTypeHandlerRegistry();
  final ResultMap rm = new ResultMap.Builder(config, "keyResultMap", Integer.class, new ArrayList<ResultMapping>())
      .build();

  MappedStatement kms = new MappedStatement.Builder(config, "insertAuthor!selectKey", new StaticSqlSource(config,"SELECT 123456 as id FROM SYSIBM.SYSDUMMY1"), SqlCommandType.SELECT)
      .keyProperty("id")
      .resultMaps(new ArrayList<ResultMap>() {
        {
          add(rm);
        }
      })
      .build();
  config.addMappedStatement(kms);
  MappedStatement ms = new MappedStatement.Builder(config, "insertAuthor", new DynamicSqlSource(config, new TextSqlNode("INSERT INTO author (id,username,password,email,bio,favourite_section) values(#{id},#{username},#{password},#{email},#{bio:VARCHAR},#{favouriteSection})")), SqlCommandType.INSERT)
      .parameterMap(
          new ParameterMap.Builder(config, "defaultParameterMap", Author.class, new ArrayList<ParameterMapping>() {
            {
              add(new ParameterMapping.Builder(config, "id", registry.getTypeHandler(Integer.class)).build());
              add(new ParameterMapping.Builder(config, "username", registry.getTypeHandler(String.class)).build());
              add(new ParameterMapping.Builder(config, "password", registry.getTypeHandler(String.class)).build());
              add(new ParameterMapping.Builder(config, "email", registry.getTypeHandler(String.class)).build());
              add(new ParameterMapping.Builder(config, "bio", registry.getTypeHandler(String.class)).jdbcType(JdbcType.VARCHAR).build());
              add(new ParameterMapping.Builder(config, "favouriteSection", registry.getTypeHandler(Section.class)).jdbcType(JdbcType.VARCHAR).build());
            }
          }).build())
      .cache(authorCache)
      .keyGenerator(new SelectKeyGenerator(kms, true))
      .keyProperty("id")
      .build();
  return ms;
}

Source File: XMLStatementBuilder.java From mybatis with Apache License 2.0

5 votes

private void parseSelectKeyNode(String id, XNode nodeToHandle, Class<?> parameterTypeClass, LanguageDriver langDriver, String databaseId) {
  String resultType = nodeToHandle.getStringAttribute("resultType");
  Class<?> resultTypeClass = resolveClass(resultType);
  StatementType statementType = StatementType.valueOf(nodeToHandle.getStringAttribute("statementType", StatementType.PREPARED.toString()));
  String keyProperty = nodeToHandle.getStringAttribute("keyProperty");
  String keyColumn = nodeToHandle.getStringAttribute("keyColumn");
  boolean executeBefore = "BEFORE".equals(nodeToHandle.getStringAttribute("order", "AFTER"));

  //defaults
  boolean useCache = false;
  boolean resultOrdered = false;
  KeyGenerator keyGenerator = new NoKeyGenerator();
  Integer fetchSize = null;
  Integer timeout = null;
  boolean flushCache = false;
  String parameterMap = null;
  String resultMap = null;
  ResultSetType resultSetTypeEnum = null;

  SqlSource sqlSource = langDriver.createSqlSource(configuration, nodeToHandle, parameterTypeClass);
  SqlCommandType sqlCommandType = SqlCommandType.SELECT;

  builderAssistant.addMappedStatement(id, sqlSource, statementType, sqlCommandType,
      fetchSize, timeout, parameterMap, parameterTypeClass, resultMap, resultTypeClass,
      resultSetTypeEnum, flushCache, useCache, resultOrdered,
      keyGenerator, keyProperty, keyColumn, databaseId, langDriver, null);

  id = builderAssistant.applyCurrentNamespace(id, false);

  MappedStatement keyStatement = configuration.getMappedStatement(id, false);
  configuration.addKeyGenerator(id, new SelectKeyGenerator(keyStatement, executeBefore));
}

Source File: XMLStatementBuilder.java From mybatis with Apache License 2.0

5 votes

private void parseSelectKeyNodes(String parentId, List<XNode> list, Class<?> parameterTypeClass, LanguageDriver langDriver, String skRequiredDatabaseId) {
  for (XNode nodeToHandle : list) {
    String id = parentId + SelectKeyGenerator.SELECT_KEY_SUFFIX;
    String databaseId = nodeToHandle.getStringAttribute("databaseId");
    if (databaseIdMatchesCurrent(id, databaseId, skRequiredDatabaseId)) {
      parseSelectKeyNode(id, nodeToHandle, parameterTypeClass, langDriver, databaseId);
    }
  }
}

Source File: MapperAnnotationBuilder.java From mybatis with Apache License 2.0

5 votes

private KeyGenerator handleSelectKeyAnnotation(SelectKey selectKeyAnnotation, String baseStatementId, Class<?> parameterTypeClass, LanguageDriver languageDriver) {
  String id = baseStatementId + SelectKeyGenerator.SELECT_KEY_SUFFIX;
  Class<?> resultTypeClass = selectKeyAnnotation.resultType();
  StatementType statementType = selectKeyAnnotation.statementType();
  String keyProperty = selectKeyAnnotation.keyProperty();
  String keyColumn = selectKeyAnnotation.keyColumn();
  boolean executeBefore = selectKeyAnnotation.before();

  // defaults
  boolean useCache = false;
  KeyGenerator keyGenerator = new NoKeyGenerator();
  Integer fetchSize = null;
  Integer timeout = null;
  boolean flushCache = false;
  String parameterMap = null;
  String resultMap = null;
  ResultSetType resultSetTypeEnum = null;

  SqlSource sqlSource = buildSqlSourceFromStrings(selectKeyAnnotation.statement(), parameterTypeClass, languageDriver);
  SqlCommandType sqlCommandType = SqlCommandType.SELECT;

  assistant.addMappedStatement(id, sqlSource, statementType, sqlCommandType, fetchSize, timeout, parameterMap, parameterTypeClass, resultMap, resultTypeClass, resultSetTypeEnum,
      flushCache, useCache, false,
      keyGenerator, keyProperty, keyColumn, null, languageDriver, null);

  id = assistant.applyCurrentNamespace(id, false);

  MappedStatement keyStatement = configuration.getMappedStatement(id, false);
  SelectKeyGenerator answer = new SelectKeyGenerator(keyStatement, executeBefore);
  configuration.addKeyGenerator(id, answer);
  return answer;
}

Source File: DynamicDataSourcePlugin.java From EasyReport with Apache License 2.0

5 votes

private DynamicDataSourceType getDynamicDataSourceType(final MappedStatement mappedStatement) {
    final DynamicDataSourceType dynamicDataSourceType = cacheMap.get(mappedStatement.getId());
    if (dynamicDataSourceType != null) {
        return dynamicDataSourceType;
    }
    //如是不是select语句则使用主库
    if (!SqlCommandType.SELECT.equals(mappedStatement.getSqlCommandType())) {
        return DynamicDataSourceType.WRITE;
    }
    //selectKey为自增id查询主键(SELECT LAST_INSERT_ID())方法,使用主库
    if (mappedStatement.getId().contains(SelectKeyGenerator.SELECT_KEY_SUFFIX)) {
        return DynamicDataSourceType.WRITE;
    }
    return DynamicDataSourceType.READ;
}

Source File: ExecutorTestHelper.java From mybaties with Apache License 2.0

5 votes

public static MappedStatement prepareInsertAuthorMappedStatementWithBeforeAutoKey(final Configuration config) {
  final TypeHandlerRegistry registry = config.getTypeHandlerRegistry();
  final ResultMap rm = new ResultMap.Builder(config, "keyResultMap", Integer.class, new ArrayList<ResultMapping>())
      .build();

  MappedStatement kms = new MappedStatement.Builder(config, "insertAuthor!selectKey", new StaticSqlSource(config,"SELECT 123456 as id FROM SYSIBM.SYSDUMMY1"), SqlCommandType.SELECT)
      .keyProperty("id")
      .resultMaps(new ArrayList<ResultMap>() {
        {
          add(rm);
        }
      })
      .build();
  config.addMappedStatement(kms);
  MappedStatement ms = new MappedStatement.Builder(config, "insertAuthor", new DynamicSqlSource(config, new TextSqlNode("INSERT INTO author (id,username,password,email,bio,favourite_section) values(#{id},#{username},#{password},#{email},#{bio:VARCHAR},#{favouriteSection})")), SqlCommandType.INSERT)
      .parameterMap(
          new ParameterMap.Builder(config, "defaultParameterMap", Author.class, new ArrayList<ParameterMapping>() {
            {
              add(new ParameterMapping.Builder(config, "id", registry.getTypeHandler(Integer.class)).build());
              add(new ParameterMapping.Builder(config, "username", registry.getTypeHandler(String.class)).build());
              add(new ParameterMapping.Builder(config, "password", registry.getTypeHandler(String.class)).build());
              add(new ParameterMapping.Builder(config, "email", registry.getTypeHandler(String.class)).build());
              add(new ParameterMapping.Builder(config, "bio", registry.getTypeHandler(String.class)).jdbcType(JdbcType.VARCHAR).build());
              add(new ParameterMapping.Builder(config, "favouriteSection", registry.getTypeHandler(Section.class)).jdbcType(JdbcType.VARCHAR).build());
            }
          }).build())
      .cache(authorCache)
      .keyGenerator(new SelectKeyGenerator(kms, true))
      .keyProperty("id")
      .build();
  return ms;
}

Source File: XMLStatementBuilder.java From mybaties with Apache License 2.0

5 votes

private void parseSelectKeyNode(String id, XNode nodeToHandle, Class<?> parameterTypeClass, LanguageDriver langDriver, String databaseId) {
  String resultType = nodeToHandle.getStringAttribute("resultType");
  Class<?> resultTypeClass = resolveClass(resultType);
  StatementType statementType = StatementType.valueOf(nodeToHandle.getStringAttribute("statementType", StatementType.PREPARED.toString()));
  String keyProperty = nodeToHandle.getStringAttribute("keyProperty");
  String keyColumn = nodeToHandle.getStringAttribute("keyColumn");
  boolean executeBefore = "BEFORE".equals(nodeToHandle.getStringAttribute("order", "AFTER"));

  //defaults
  boolean useCache = false;
  boolean resultOrdered = false;
  KeyGenerator keyGenerator = new NoKeyGenerator();
  Integer fetchSize = null;
  Integer timeout = null;
  boolean flushCache = false;
  String parameterMap = null;
  String resultMap = null;
  ResultSetType resultSetTypeEnum = null;

  SqlSource sqlSource = langDriver.createSqlSource(configuration, nodeToHandle, parameterTypeClass);
  SqlCommandType sqlCommandType = SqlCommandType.SELECT;

  builderAssistant.addMappedStatement(id, sqlSource, statementType, sqlCommandType,
      fetchSize, timeout, parameterMap, parameterTypeClass, resultMap, resultTypeClass,
      resultSetTypeEnum, flushCache, useCache, resultOrdered,
      keyGenerator, keyProperty, keyColumn, databaseId, langDriver, null);

  id = builderAssistant.applyCurrentNamespace(id, false);

  MappedStatement keyStatement = configuration.getMappedStatement(id, false);
  configuration.addKeyGenerator(id, new SelectKeyGenerator(keyStatement, executeBefore));
}

Source File: XMLStatementBuilder.java From mybaties with Apache License 2.0

5 votes

private void parseSelectKeyNodes(String parentId, List<XNode> list, Class<?> parameterTypeClass, LanguageDriver langDriver, String skRequiredDatabaseId) {
  for (XNode nodeToHandle : list) {
    String id = parentId + SelectKeyGenerator.SELECT_KEY_SUFFIX;
    String databaseId = nodeToHandle.getStringAttribute("databaseId");
    if (databaseIdMatchesCurrent(id, databaseId, skRequiredDatabaseId)) {
      parseSelectKeyNode(id, nodeToHandle, parameterTypeClass, langDriver, databaseId);
    }
  }
}

Source File: MapperAnnotationBuilder.java From mybaties with Apache License 2.0

5 votes

private KeyGenerator handleSelectKeyAnnotation(SelectKey selectKeyAnnotation, String baseStatementId, Class<?> parameterTypeClass, LanguageDriver languageDriver) {
  String id = baseStatementId + SelectKeyGenerator.SELECT_KEY_SUFFIX;
  Class<?> resultTypeClass = selectKeyAnnotation.resultType();
  StatementType statementType = selectKeyAnnotation.statementType();
  String keyProperty = selectKeyAnnotation.keyProperty();
  String keyColumn = selectKeyAnnotation.keyColumn();
  boolean executeBefore = selectKeyAnnotation.before();

  // defaults
  boolean useCache = false;
  KeyGenerator keyGenerator = new NoKeyGenerator();
  Integer fetchSize = null;
  Integer timeout = null;
  boolean flushCache = false;
  String parameterMap = null;
  String resultMap = null;
  ResultSetType resultSetTypeEnum = null;

  SqlSource sqlSource = buildSqlSourceFromStrings(selectKeyAnnotation.statement(), parameterTypeClass, languageDriver);
  SqlCommandType sqlCommandType = SqlCommandType.SELECT;

  assistant.addMappedStatement(id, sqlSource, statementType, sqlCommandType, fetchSize, timeout, parameterMap, parameterTypeClass, resultMap, resultTypeClass, resultSetTypeEnum,
      flushCache, useCache, false,
      keyGenerator, keyProperty, keyColumn, null, languageDriver, null);

  id = assistant.applyCurrentNamespace(id, false);

  MappedStatement keyStatement = configuration.getMappedStatement(id, false);
  SelectKeyGenerator answer = new SelectKeyGenerator(keyStatement, executeBefore);
  configuration.addKeyGenerator(id, answer);
  return answer;
}

Source File: DynamicDataSourcePlugin.java From dk-foundation with GNU Lesser General Public License v2.1

5 votes

@Override
public Object intercept(Invocation invocation) throws Throwable {
    boolean synchronizationActive = TransactionSynchronizationManager.isSynchronizationActive();
    if(!synchronizationActive) {
        Object[] objects = invocation.getArgs();
        MappedStatement ms = (MappedStatement) objects[0];
        String dataSourceKey="";
        if((dataSourceKey = CACHE_MAP.get(ms.getId())) == null) {
            if(ms.getSqlCommandType().equals(SqlCommandType.SELECT)) {
                //!selectKey 为自增id查询主键(SELECT LAST_INSERT_ID() )方法，使用主库
                if(ms.getId().contains(SelectKeyGenerator.SELECT_KEY_SUFFIX)) {
                    dataSourceKey = DynamicDataSourceKey.MASTER;
                } else {
                    BoundSql boundSql = ms.getSqlSource().getBoundSql(objects[1]);
                    String sql = boundSql.getSql().replaceAll("[\\t\\n\\r]", " ");
                    if(PATTERN.matcher(sql).matches()) {
                        dataSourceKey = DynamicDataSourceKey.MASTER;
                    } else {
                        dataSourceKey = DynamicDataSourceKey.READ_RANDOM_PROXY;
                    }
                }
            }else{
                dataSourceKey = DynamicDataSourceKey.MASTER;
            }
            logger.warn("Method [{}] use [{}] Strategy, SqlCommandType [{}].", ms.getId(), dataSourceKey, ms.getSqlCommandType().name());
            CACHE_MAP.put(ms.getId(), dataSourceKey);
        }
        DynamicDataSourceKey.setDataSource(dataSourceKey,false);
    }

    return invocation.proceed();
}

Source File: XMLStatementBuilder.java From mybatis with Apache License 2.0

4 votes

public void parseStatementNode() {
   String id = context.getStringAttribute("id");
   String databaseId = context.getStringAttribute("databaseId");

   //如果databaseId不匹配，退出
   if (!databaseIdMatchesCurrent(id, databaseId, this.requiredDatabaseId)) {
     return;
   }

   //暗示驱动程序每次批量返回的结果行数
   Integer fetchSize = context.getIntAttribute("fetchSize");
   //超时时间
   Integer timeout = context.getIntAttribute("timeout");
   //引用外部 parameterMap,已废弃
   String parameterMap = context.getStringAttribute("parameterMap");
   //参数类型
   String parameterType = context.getStringAttribute("parameterType");
   Class<?> parameterTypeClass = resolveClass(parameterType);
   //引用外部的 resultMap(高级功能)
   String resultMap = context.getStringAttribute("resultMap");
   //结果类型
   String resultType = context.getStringAttribute("resultType");
   //脚本语言,mybatis3.2的新功能
   String lang = context.getStringAttribute("lang");
   //得到语言驱动
   LanguageDriver langDriver = getLanguageDriver(lang);

   Class<?> resultTypeClass = resolveClass(resultType);
   //结果集类型，FORWARD_ONLY|SCROLL_SENSITIVE|SCROLL_INSENSITIVE 中的一种
   String resultSetType = context.getStringAttribute("resultSetType");
   //语句类型, STATEMENT|PREPARED|CALLABLE 的一种
   StatementType statementType = StatementType.valueOf(context.getStringAttribute("statementType", StatementType.PREPARED.toString()));
   ResultSetType resultSetTypeEnum = resolveResultSetType(resultSetType);

   //获取命令类型(select|insert|update|delete)
   String nodeName = context.getNode().getNodeName();
   SqlCommandType sqlCommandType = SqlCommandType.valueOf(nodeName.toUpperCase(Locale.ENGLISH));
   boolean isSelect = sqlCommandType == SqlCommandType.SELECT;
   boolean flushCache = context.getBooleanAttribute("flushCache", !isSelect);
   //是否要缓存select结果
   boolean useCache = context.getBooleanAttribute("useCache", isSelect);
   //仅针对嵌套结果 select 语句适用：如果为 true，就是假设包含了嵌套结果集或是分组了，这样的话当返回一个主结果行的时候，就不会发生有对前面结果集的引用的情况。
   //这就使得在获取嵌套的结果集的时候不至于导致内存不够用。默认值：false。 
   boolean resultOrdered = context.getBooleanAttribute("resultOrdered", false);

   // Include Fragments before parsing
   //解析之前先解析<include>SQL片段
   XMLIncludeTransformer includeParser = new XMLIncludeTransformer(configuration, builderAssistant);
   includeParser.applyIncludes(context.getNode());

   // Parse selectKey after includes and remove them.
   //解析之前先解析<selectKey>
   processSelectKeyNodes(id, parameterTypeClass, langDriver);
   
   // Parse the SQL (pre: <selectKey> and <include> were parsed and removed)
   //解析成SqlSource，一般是DynamicSqlSource
   SqlSource sqlSource = langDriver.createSqlSource(configuration, context, parameterTypeClass);
   String resultSets = context.getStringAttribute("resultSets");
   //(仅对 insert 有用) 标记一个属性, MyBatis 会通过 getGeneratedKeys 或者通过 insert 语句的 selectKey 子元素设置它的值
   String keyProperty = context.getStringAttribute("keyProperty");
   //(仅对 insert 有用) 标记一个属性, MyBatis 会通过 getGeneratedKeys 或者通过 insert 语句的 selectKey 子元素设置它的值
   String keyColumn = context.getStringAttribute("keyColumn");
   KeyGenerator keyGenerator;
   String keyStatementId = id + SelectKeyGenerator.SELECT_KEY_SUFFIX;
   keyStatementId = builderAssistant.applyCurrentNamespace(keyStatementId, true);
   if (configuration.hasKeyGenerator(keyStatementId)) {
     keyGenerator = configuration.getKeyGenerator(keyStatementId);
   } else {
     keyGenerator = context.getBooleanAttribute("useGeneratedKeys",
         configuration.isUseGeneratedKeys() && SqlCommandType.INSERT.equals(sqlCommandType))
         ? new Jdbc3KeyGenerator() : new NoKeyGenerator();
   }

//又去调助手类
   builderAssistant.addMappedStatement(id, sqlSource, statementType, sqlCommandType,
       fetchSize, timeout, parameterMap, parameterTypeClass, resultMap, resultTypeClass,
       resultSetTypeEnum, flushCache, useCache, resultOrdered, 
       keyGenerator, keyProperty, keyColumn, databaseId, langDriver, resultSets);
 }

Source File: XMLStatementBuilder.java From mybaties with Apache License 2.0

4 votes

public void parseStatementNode() {
   String id = context.getStringAttribute("id");
   String databaseId = context.getStringAttribute("databaseId");

   //如果databaseId不匹配，退出
   if (!databaseIdMatchesCurrent(id, databaseId, this.requiredDatabaseId)) {
     return;
   }

   //暗示驱动程序每次批量返回的结果行数
   Integer fetchSize = context.getIntAttribute("fetchSize");
   //超时时间
   Integer timeout = context.getIntAttribute("timeout");
   //引用外部 parameterMap,已废弃
   String parameterMap = context.getStringAttribute("parameterMap");
   //参数类型
   String parameterType = context.getStringAttribute("parameterType");
   Class<?> parameterTypeClass = resolveClass(parameterType);
   //引用外部的 resultMap(高级功能)
   String resultMap = context.getStringAttribute("resultMap");
   //结果类型
   String resultType = context.getStringAttribute("resultType");
   //脚本语言,mybatis3.2的新功能
   String lang = context.getStringAttribute("lang");
   //得到语言驱动
   LanguageDriver langDriver = getLanguageDriver(lang);

   Class<?> resultTypeClass = resolveClass(resultType);
   //结果集类型，FORWARD_ONLY|SCROLL_SENSITIVE|SCROLL_INSENSITIVE 中的一种
   String resultSetType = context.getStringAttribute("resultSetType");
   //语句类型, STATEMENT|PREPARED|CALLABLE 的一种
   StatementType statementType = StatementType.valueOf(context.getStringAttribute("statementType", StatementType.PREPARED.toString()));
   ResultSetType resultSetTypeEnum = resolveResultSetType(resultSetType);

   //获取命令类型(select|insert|update|delete)
   String nodeName = context.getNode().getNodeName();
   SqlCommandType sqlCommandType = SqlCommandType.valueOf(nodeName.toUpperCase(Locale.ENGLISH));
   boolean isSelect = sqlCommandType == SqlCommandType.SELECT;
   boolean flushCache = context.getBooleanAttribute("flushCache", !isSelect);
   //是否要缓存select结果
   boolean useCache = context.getBooleanAttribute("useCache", isSelect);
   //仅针对嵌套结果 select 语句适用：如果为 true，就是假设包含了嵌套结果集或是分组了，这样的话当返回一个主结果行的时候，就不会发生有对前面结果集的引用的情况。
   //这就使得在获取嵌套的结果集的时候不至于导致内存不够用。默认值：false。 
   boolean resultOrdered = context.getBooleanAttribute("resultOrdered", false);

   // Include Fragments before parsing
   //解析之前先解析<include>SQL片段
   XMLIncludeTransformer includeParser = new XMLIncludeTransformer(configuration, builderAssistant);
   includeParser.applyIncludes(context.getNode());

   // Parse selectKey after includes and remove them.
   //解析之前先解析<selectKey>
   processSelectKeyNodes(id, parameterTypeClass, langDriver);
   
   // Parse the SQL (pre: <selectKey> and <include> were parsed and removed)
   //解析成SqlSource，一般是DynamicSqlSource
   SqlSource sqlSource = langDriver.createSqlSource(configuration, context, parameterTypeClass);
   String resultSets = context.getStringAttribute("resultSets");
   //(仅对 insert 有用) 标记一个属性, MyBatis 会通过 getGeneratedKeys 或者通过 insert 语句的 selectKey 子元素设置它的值
   String keyProperty = context.getStringAttribute("keyProperty");
   //(仅对 insert 有用) 标记一个属性, MyBatis 会通过 getGeneratedKeys 或者通过 insert 语句的 selectKey 子元素设置它的值
   String keyColumn = context.getStringAttribute("keyColumn");
   KeyGenerator keyGenerator;
   String keyStatementId = id + SelectKeyGenerator.SELECT_KEY_SUFFIX;
   keyStatementId = builderAssistant.applyCurrentNamespace(keyStatementId, true);
   if (configuration.hasKeyGenerator(keyStatementId)) {
     keyGenerator = configuration.getKeyGenerator(keyStatementId);
   } else {
     keyGenerator = context.getBooleanAttribute("useGeneratedKeys",
         configuration.isUseGeneratedKeys() && SqlCommandType.INSERT.equals(sqlCommandType))
         ? new Jdbc3KeyGenerator() : new NoKeyGenerator();
   }

//又去调助手类
   builderAssistant.addMappedStatement(id, sqlSource, statementType, sqlCommandType,
       fetchSize, timeout, parameterMap, parameterTypeClass, resultMap, resultTypeClass,
       resultSetTypeEnum, flushCache, useCache, resultOrdered, 
       keyGenerator, keyProperty, keyColumn, databaseId, langDriver, resultSets);
 }

Source File: DynamicDataSourceInterceptor.java From Project with Apache License 2.0

4 votes

@Override
// 下面方法拦截之后，决定使用哪一个数据源
public Object intercept(Invocation invocation) throws Throwable {
    boolean synchronizationActive =
            TransactionSynchronizationManager.isActualTransactionActive();
    // 接收 mybatis传过来的操作的参数,然后进行比对；
    Object[] objects = invocation.getArgs();
    // 相当于获取 SQL 语句最前面，就是SQL是增？删？。。
    MappedStatement ms = (MappedStatement) objects[0];
    String lookupKey =  DynamicDataSourceHolder.DB_MASTER;
    // 如果操作时事务的
    if (synchronizationActive != true){

        // 读方法
        if (ms.getSqlCommandType().equals(SqlCommandType.SELECT)){
            // 如果 selectKey 为自增 id 查询主键，即mybatis 使用了select Last_insert_ID()，方法, 这是用使用主库
            if (ms.getId().contains(SelectKeyGenerator.SELECT_KEY_SUFFIX)){
                lookupKey = DynamicDataSourceHolder.DB_MASTER;
            }else{
                // 获取 SQL 语句，然后将所有的制表符、换行符等等换成空格；
                BoundSql boundSql = ms.getSqlSource().getBoundSql(objects[1]);
                String sql = boundSql.getSql().toLowerCase(Locale.CHINA).replaceAll("[\\t\\n" +
                        "\\r]"," ");
                // 使用正则判断是不是插入、删除、更新方法；
                if (sql.matches(REGEX)){
                    lookupKey = DynamicDataSourceHolder.DB_MASTER;
                }else {
                    lookupKey = DynamicDataSourceHolder.DB_SLAVE;
                }
            }
        }
    }else {
        // 如果是事务操作，一般都是写操作，使用主库
        lookupKey = DynamicDataSourceHolder.DB_MASTER;
    }
    // 日志信息
    logger.debug("设置的方法[{}] use [{}] Strategy, SqlCommanType [{}]..",ms.getId(), lookupKey,
            ms.getSqlCommandType().name());

    DynamicDataSourceHolder.setDbType(lookupKey);
    // 然后正式开始进行操作
    return invocation.proceed();
}

org.apache.ibatis.executor.keygen.SelectKeyGenerator Java Examples