mybatis-3.4.6 foreach 自增主键

系列

• mybatis-3.4.6 配置介绍
• mybatis-3.4.6 顶层配置解析
• mybatis-3.4.6 子配置解析
• mybatis-3.4.6 mapper解析
• mybatis-3.4.6 SQL执行流程
• mybatis-3.4.6 SqlSession执行过程
• mybatis-3.4.6 缓存介绍
• mybatis-3.4.6 自增主键
• mybatis-3.4.6 foreach 自增主键
• mybatis-3.4.6 事务管理

开篇

• 这个系列是基于mybatis-3.4.6版本的源码解析，这篇文章主要分析mybatis的foreach主键生成的逻辑。

• 这篇文章在mybatis-3.4.6 自增主键的基础上针对批量插入foreach的自增主键做个补充。

foreach

    INSERT  INTO imc_user (`user_nick`) VALUES 
      
           (#{item.userNick})
      


public class MybatisHelloWorld {

    public static void main(String[] args) {

        String resouce = "configuration.xml";
        Reader reader;
        try {
            reader = Resources.getResourceAsReader(resouce);
            SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);

            SqlSession sqlSession = sqlSessionFactory.openSession();
            try {
                UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
                ImcUser imcUser = new ImcUser();
                imcUser.setUserNick("demo");

                ImcUser imcUser1 = new ImcUser();
                imcUser1.setUserNick("demo1");

                List imcUserList = new ArrayList<>();
                imcUserList.add(imcUser);
                imcUserList.add(imcUser1);

                userMapper.bachAddUser(imcUserList);

                sqlSession.commit();

                System.out.println(imcUserList.get(1).getUserId());
            } finally {
                sqlSession.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}

• foreach的批量插入的代码如上图所示。

ForEachHandler

  private class ForEachHandler implements NodeHandler {
    public ForEachHandler() {
      // Prevent Synthetic Access
    }

    @Override
    public void handleNode(XNode nodeToHandle, List targetContents) {
      MixedSqlNode mixedSqlNode = parseDynamicTags(nodeToHandle);
      String collection = nodeToHandle.getStringAttribute("collection");
      String item = nodeToHandle.getStringAttribute("item");
      String index = nodeToHandle.getStringAttribute("index");
      String open = nodeToHandle.getStringAttribute("open");
      String close = nodeToHandle.getStringAttribute("close");
      String separator = nodeToHandle.getStringAttribute("separator");
      ForEachSqlNode forEachSqlNode = new ForEachSqlNode(configuration, mixedSqlNode, collection, index, item, open, close, separator);
      targetContents.add(forEachSqlNode);
    }
  }

• ForEachHandler的参数如上所示。

public class Jdbc3KeyGenerator implements KeyGenerator {

  public static final Jdbc3KeyGenerator INSTANCE = new Jdbc3KeyGenerator();

  @Override
  public void processAfter(Executor executor, MappedStatement ms, Statement stmt, Object parameter) {
    processBatch(ms, stmt, getParameters(parameter));
  }

  public void processBatch(MappedStatement ms, Statement stmt, Collection