Cglib根据数据库表数据动态生成对象

Posted 2021-01-20 barrywxx

最近有个任务：根据查询SQL直接导出报表

实现关键是，怎么根据sql查询的数据动态生成对象列表，想到Cglib动态代理实现

废话少说，上代码：

定义动态生成Java Bean类：

import java.util

import net.sf.cglib.beans.{BeanGenerator, BeanMap}

/**
  * 动态Bean生成
  *
  * @author BarryWang create at 2018/6/19 11:54
  * @version 0.0.1
  */
class DynamicBean {
  private var `object`: AnyRef = null
  private var beanMap: BeanMap = null

  def this(fieldTypeMap: util.Map[String, AnyRef]) {
    this()
    this.`object` = generateObject(fieldTypeMap)
    this.beanMap = BeanMap.create(this.`object`)
  }

  /**
    * 生成对象
    *
    * @param fieldTypeMap 域及类型Map
    * @return
    */
  private def generateObject(fieldTypeMap: util.Map[String, AnyRef]) = {
    val generator = new BeanGenerator
    val keySet = fieldTypeMap.keySet
    val i = keySet.iterator
    while (i.hasNext) {
      val key = i.next
      generator.addProperty(key, fieldTypeMap.get(key).asInstanceOf[Class[_]])
    }
    generator.create
  }

  /**
    * 设置域值
    *
    * @param filedName 域名
    * @param value     值
    */
  def setValue(filedName: String, value: AnyRef): Unit = {
    this.beanMap.put(filedName, value)
  }

  /**
    * 获取域值
    *
    * @param fieldName 域名
    * @return
    */
  def getValue(fieldName: String): AnyRef = this.beanMap.get(fieldName)

  /**
    * 最终对象
    *
    * @return
    */
  def getObject: AnyRef = this.`object`
}

SQL查询数据转对象：

  /**
    * 根据数据查出数据转成对象列表
    * @param database 数据库
    * @param querySql 查询SQl
    * @return
    */
  def getObjectDataList(database: String, querySql: String): ArrayList[Object] = {
    println(s"database:${database} sql:${querySql}")
    val rs = DataGenerator.getResultSet(database, querySql)
    val md = rs.getMetaData
    val colCount = md.getColumnCount
    val fieldValMap = new JavaHashMap[String, AnyRef]()
    for (i <- 0 to colCount - 1) {
      fieldValMap.put(underLineToCamel(md.getColumnName(i + 1)), Class.forName("java.lang.String"))
    }
    // 生成动态 Bean
    val returnList = new ArrayList[Object]();
    while (rs.next()) {
      val objectBean = new DynamicBean(fieldValMap);
      for (i <- 0 to colCount - 1) {
        val data = getData(md, i+1, rs)
        objectBean.setValue(underLineToCamel(md.getColumnName(i + 1)), data)
      }
//      println(">> " + objectBean.getValue("zhCnName"))
      returnList.add(objectBean.getObject)
    }
    rs.close()
    returnList
  }

  def underLineToCamel(name: String): String = {
    val result = new StringBuilder
    // 快速检查
    if (name == null || name.isEmpty) { // 没必要转换
      return ""
      //        } else if (!name.contains("_")) {
      //            // 不含下划线，仅将首字母小写
      //            return name.substring(0, 1).toLowerCase() + name.substring(1);
    }
    // 用下划线将原始字符串分割
    val camels = name.split("_")
    for (camel <- camels) { // 跳过原始字符串中开头、结尾的下换线或双重下划线
      // 处理真正的驼峰片段
      if (result.length == 0) { // 第一个驼峰片段，全部字母都小写
        result.append(camel.toLowerCase)
      }
      else { // 其他的驼峰片段，首字母大写
        result.append(camel.substring(0, 1).toUpperCase)
        result.append(camel.substring(1).toLowerCase)
      }
    }
    result.toString
  }

/**
  * 从ResultSet取数
  * @param md
  * @param index
  * @param rs
  * @return
  */
def getData(md: ResultSetMetaData, index: Int, rs: ResultSet): String = {
  md.getColumnType(index)  match {
    case Types.DECIMAL => {
      val value = rs.getBigDecimal(index)
      val bigDecimal = value == null match {
        case true => "0.0000"
        case false => value.setScale(4, RoundingMode.HALF_UP).toString()
      }
      return bigDecimal
    }
    case Types.TIMESTAMP =>{
      val value = rs.getTimestamp(index)
      val timestamp = value == null match {
        case true => ""
        case false => DateTools.format(new Date(rs.getTimestamp(index).getTime))
      }
      return timestamp
    }
    case Types.DATE => {
      val value = rs.getDate(index)
      val date = value == null match {
        case true => ""
        case false => DateTools.format(rs.getDate(index), DateTools.DATE_PATTERN)
      }
      return date
    }
    case _ => {
      val value = rs.getObject(index)
      val data = value == null match {
        case true => ""
        case false => rs.getObject(index).toString
      }
      return data
    }
  }
}