jdbc的使用拼接个参数（in）的使用方法

骑士李四记录：

在有连接池的情况下，对有多个参数的sql拼接和添加入参的方法如下。
代码一：

 StringBuilder queryBuilder = new StringBuilder();
 queryBuilder.append("SELECT a, b, c" +
                     "FROM  `table` " +
                     "a  in ( ");
 //拼接参数 ?
 for ( int i = 0; i < aids.size(); i++) {
     queryBuilder.append( " ?");
     if (i != ids.size() - 1) {
         queryBuilder.append( ",");
     }
 }
 queryBuilder.append(") and b in (" );
 for ( int i = 0; i < bids.size(); i++) {
     queryBuilder.append( " ?");
     if (i != bids.size() - 1) {
         queryBuilder.append( ",");
     }
 }
 queryBuilder.append(") group by a" );

try {
    Connection connection = pool.getConnection();
    PreparedStatement statement = connection.prepareStatement(queryBuilder.toString());
    for ( int i = 1; i <= allIds.size(); i++) {
        statement.setString(i, allIds.get(i - 1));
    }
    ResultSet rs = statement.executeQuery();
    ResultSetMetaData metaData = rs.getMetaData();
    int columnCount = metaData.getColumnCount();
    while (rs.next()) {
        JSONObject jsonObject = new JSONObject();
        for (int i = 1; i <= columnCount; i++) {
            if (rs.getObject(i) != null) {
                jsonObject.put(metaData.getColumnLabel(i), rs.getObject(i));  //查询结果
            }
        }
        AiEdVO resultVO = jsonObject.toJavaObject(AiEdVO.class);
        logger.info("ccc resultVO: {}", resultVO);
        results.add(resultVO);
    }
} catch (Exception e) {
    logger.error("query nc_ip list failed：{}", e.getMessage());
    throw e;
}

代码二：
用 这句话替代了上面的循环拼参数
String sql = MessageFormat.format(query,ids,ids);
MessageFormat.format是根据顺序和占位符来对应插入的

 String query =
               "SELECT a, b, c" +
               "FROM  `table` " +
               "a  in ( {0}) and b in({1}) "
               "group by a, b";
  //对传入的参数用，分开               
  String ids = list.stream().map(s -> "\'" + s + "\'").collect(Collectors.joining(", ")); 
  //把参数配置进去
  String sql = MessageFormat.format(query,ids,ids);     //in({0})和in({1})传入一样的参数  
  try {
    Connection connection = pool.getConnection();
    PreparedStatement statement = connection.prepareStatement(sql);
    ResultSet rs = statement.executeQuery();
    ResultSetMetaData metaData = rs.getMetaData();
    int columnCount = metaData.getColumnCount();
    while (rs.next()) {
        JSONObject jsonObject = new JSONObject();
        for (int i = 1; i <= columnCount; i++) {
            if (rs.getObject(i) != null) {
                jsonObject.put(metaData.getColumnLabel(i), rs.getObject(i));  //查询结果
            }
        }
        AiEdVO resultVO = jsonObject.toJavaObject(AiEdVO.class);
        logger.info("ccc resultVO: {}", resultVO);
        results.add(resultVO);
    }
} catch (Exception e) {
    logger.error("query nc_ip list failed：{}", e.getMessage());
    throw e;
}