ResultSet转为实体对象

package org.test;

import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;

/**
* <p>
* Title: LoonFramework
* </p>
* <p>
* Description:
* </p>
* <p>
* Copyright: Copyright (c) 2007
* </p>
* <p>
* Company: LoonFramework
* </p>
* 
* @author chenpeng
* @email：[e-mail]
* @version 0.1
*/
public class ConnectionTest {

   /**
   * 匹配指定class中数据,并返回包含get和set方法的object
   * 
   * @author chenpeng
   * @param clazz
   * @param beanProperty
   * @return
   */
   private Object[] beanMatch(Class clazz, String beanProperty) {
       Object[] result = new Object[2];
       char beanPropertyChars[] = beanProperty.toCharArray();
       beanPropertyChars[0] = Character.toUpperCase(beanPropertyChars[0]);
       String s = new String(beanPropertyChars);
       String names[] = { ("set" + s).intern(), ("get" + s).intern(),
               ("is" + s).intern(), ("write" + s).intern(),
               ("read" + s).intern() };
       Method getter = null;
       Method setter = null;
       Method methods[] = clazz.getMethods();
       for (int i = 0; i < methods.length; i++) {
           Method method = methods[i];
           // 只取公共字段
           if (!Modifier.isPublic(method.getModifiers()))
               continue;
           String methodName = method.getName().intern();
           for (int j = 0; j < names.length; j++) {
               String name = names[j];
               if (!name.equals(methodName))
                   continue;
               if (methodName.startsWith("set")
                       || methodName.startsWith("read"))
                   setter = method;
               else
                   getter = method;
           }
       }
       result[0] = getter;
       result[1] = setter;
       return result;
   }

   /**
   * 为bean自动注入数据
   * 
   * @author chenpeng
   * @param object
   * @param beanProperty
   */
   private void beanRegister(Object object, String beanProperty, String value) {
       Object[] beanObject = beanMatch(object.getClass(), beanProperty);
       Object[] cache = new Object[1];
       Method getter = (Method) beanObject[0];
       Method setter = (Method) beanObject[1];
       try {
           // 通过get获得方法类型
           String methodType = getter.getReturnType().getName();
           if (methodType.equalsIgnoreCase("long")) {
               cache[0] = new Long(value);
               setter.invoke(object, cache);
           } else if (methodType.equalsIgnoreCase("int")
                   || methodType.equalsIgnoreCase("integer")) {
               cache[0] = new Integer(value);
               setter.invoke(object, cache);
           } else if (methodType.equalsIgnoreCase("short")) {
               cache[0] = new Short(value);
               setter.invoke(object, cache);
           } else if (methodType.equalsIgnoreCase("float")) {
               cache[0] = new Float(value);
               setter.invoke(object, cache);
           } else if (methodType.equalsIgnoreCase("double")) {
               cache[0] = new Double(value);
               setter.invoke(object, cache);
           } else if (methodType.equalsIgnoreCase("boolean")) {
               cache[0] = new Boolean(value);
               setter.invoke(object, cache);
           } else if (methodType.equalsIgnoreCase("java.lang.String")) {
               cache[0] = value;
               setter.invoke(object, cache);
           } else if (methodType.equalsIgnoreCase("java.io.InputStream")) {
           } else if (methodType.equalsIgnoreCase("char")) {
               cache[0] = (Character.valueOf(value.charAt(0)));
               setter.invoke(object, cache);
           }
       } catch (Exception e) {
           e.printStackTrace();
       }
   }

   /**
   * 转换connection查询结果为指定对象实体集合。
   * 
   * @author chenpeng
   * @param connection
   * @param clazz
   * @param sql
   * @return
   */
   public Collection get(final Connection connection, final Class clazz,
           final String sql) {
       // 创建PreparedStatement
       PreparedStatement ptmt = null;
       // 创建resultset
       ResultSet rset = null;
       // 创建collection
       Collection collection = null;
       try {
           // 赋予实例
           ptmt = connection.prepareStatement(sql);
           rset = ptmt.executeQuery();
           collection = get(rset, clazz);
       } catch (SQLException e) {
           System.err.println(e.getMessage());
       } finally {
           try {
               // 关闭rs并释放资源
               if (rset != null) {
                   rset.close();
                   rset = null;
               }
               // 关闭ps并释放资源
               if (ptmt != null) {
                   ptmt.close();
                   ptmt = null;
               }
           } catch (SQLException e) {
               System.err.println(e.getMessage());
           }
       }
       return collection;
   }

   public Collection get(final ResultSet result, final Class clazz) {
       // 创建collection
       Collection collection = null;
       try {
           ResultSetMetaData rsmd = result.getMetaData();
           // 获得数据列数
           int cols = rsmd.getColumnCount();
           // 创建等同数据列数的arraylist类型collection实例
           collection = new ArrayList(cols);
           // 遍历结果集
           while (result.next()) {
               // 创建对象
               Object object = null;
               try {
                   // 从class获得对象实体
                   object = clazz.newInstance();
               } catch (Exception e) {
               }
               // 循环每条记录
               for (int i = 1; i <= cols; i++) {
                   beanRegister(object, rsmd.getColumnName(i), result
                           .getString(i));
               }
               // 将数据插入collection
               collection.add(object);
           }
       } catch (SQLException e) {
           System.err.println(e.getMessage());
       } finally {

       }
       return collection;
   }

   public static void main(String[] args) {
       try {
           Class.forName("org.gjt.mm.mysql.Driver");
       } catch (ClassNotFoundException e) {
           e.printStackTrace();
       }
       String url = "jdbc:mysql://localhost:3306/test?useUnicode=true";
       Connection connection = null;
       PreparedStatement ps = null;
       ResultSet rs = null;
       try {
           connection = DriverManager.getConnection(url, "root", "xxxx");
           ConnectionTest test = new ConnectionTest();
           // Ltest是我测试用类，实际操作请注入相关对象，支持set，get，is，read，writer为前缀数据对，更多请继续添加。
           Collection collection = test.get(connection, Ltest.class,
                   "select * from ltest");
           for (Iterator it = collection.iterator(); it.hasNext();) {
               Ltest ltest = (Ltest) it.next();
               System.out.println(ltest.getId() + ":" + ltest.getName());
           }
       }
       // SQL异常，用于抛出SQL语句处理中所引发的错误。
       catch (SQLException e) {
           System.err.println(e.getMessage());
       }
       // finally，此标识用以包含必须访问的内容。
       finally {
           try {
               // 关闭rs并释放资源
               if (rs != null) {
                   rs.close();
                   rs = null;
               }
               // 关闭ps并释放资源
               if (ps != null) {
                   ps.close();
                   ps = null;
               }
               // 关闭connection并释放资源
               if (connection != null) {
                   connection.close();
                   connection = null;
               }
               // 如果关闭时产生异常将由此抛出
           } catch (SQLException e) {
               System.err.println(e.getMessage());
           }

       }
   }
}

________________________
前一阵写loonframework-db时，写过类似的处理方法，只不过为了效率我都是直接操作的数组对象，现改为集合对象，减少了一些处理，但大体流程如此。我框架中cache一直没有做完，所以没有为您添加，您可以用map之类做一个简单的cache来使用，目前万条数据会较慢于 ResultSet，但是可以正常使用。

评论

1 楼 naicj 2012-04-23  

楼主，可不可以给一个Ltest类啊，缺少Ltest类