简单实现一种利用反射自动封装JavaBean的JDBC查询

import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.sql.ResultSetMetaData;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Logger;

import javax.sql.rowset.CachedRowSet;

public class BeanUtil
{

    private static Logger LOG = Logger.getLogger(Logger.class.getName());

    /**
     * 通过Bean对象获取查询语句
     * 
     * @param obj 对象
     * @param tableName 表名
     * @return SQL
     */
    public static String getSQLOfSelect(Object obj, String tableName)
    {
        StringBuffer strBuffer = new StringBuffer("SELECT ");
        Class<? extends Object> objClass = obj.getClass();
        Field fields[] = objClass.getDeclaredFields();
        for (Field field : fields)
        {
            String methodName = field.getName().substring(0, 1).toUpperCase() + field.getName().substring(1);
            try
            {
                if (null != objClass.getMethod("get" + methodName))
                {
                    strBuffer.append(field.getName() + ",");
                }
            }
            catch (SecurityException e)
            {
                e.printStackTrace();
            }
            catch (NoSuchMethodException e)
            {
                e.printStackTrace();
            }
        }
        strBuffer.delete(strBuffer.length() - 1, strBuffer.length());
        strBuffer.append(" FROM " + tableName);
        LOG.info(strBuffer.toString());
        return null;
    }

    /**
     * 通过bean对象获取插入时的SQL
     * 
     * @param obj java对象
     * @param tableName 表名
     * @return SQL
     */
    public static String getSQLOfInsert(Object obj, String tableName)
    {
        String strSQL = new String("INSERT INTO " + tableName + "(#COLS) VALUES (#VALS)");
        Class<? extends Object> objClass = obj.getClass();
        Field fields[] = objClass.getDeclaredFields();
        StringBuffer cols = new StringBuffer("");
        StringBuffer values = new StringBuffer("");

        for (Field field : fields)
        {
            String methodName = "get" + field.getName().substring(0, 1).toUpperCase() + field.getName().substring(1);
            try
            {
                Method method = objClass.getMethod(methodName);
                Object o = method.invoke(obj);
                if (null != o)
                {
                    cols.append(field.getName() + ",");
                    if (o instanceof Integer || o instanceof Long || o instanceof Double)
                    {
                        values.append(o.toString() + ",");
                    }
                    else if (o instanceof String)
                    {
                        values.append("'" + o + "',");
                    }
                    else if (o instanceof java.util.Date)
                    {
                        String datestr = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format((java.util.Date) o);
                        values.append("'" + datestr + "',");
                    }
                    else
                    {
                        values.append("'" + o.toString() + "',");
                    }
                }
            }
            catch (SecurityException e)
            {
                e.printStackTrace();
                continue;
            }
            catch (NoSuchMethodException e)
            {
                e.printStackTrace();
                continue;
            }
            catch (IllegalArgumentException e)
            {
                e.printStackTrace();
            }
            catch (IllegalAccessException e)
            {
                e.printStackTrace();
            }
            catch (InvocationTargetException e)
            {
                e.printStackTrace();
            }
        }
        if (cols.length() > 1 && values.length() > 1)
        {
            cols.delete(cols.length() - 1, cols.length());
            values.delete(values.length() - 1, values.length());
            strSQL = strSQL.replace("#COLS", cols).replace("#VALS", values);
        }
        else
        {
            LOG.warning("警告：空对象无法完成操作啊");
            return null;
        }
        LOG.info(strSQL);

        return strSQL;
    }

    /**
     * 通过缓存结果集构造对象列表
     * 
     * @param clazz javaBean类
     * @param crs 缓存结果集
     * @return 对象列表
     */
    public static List<Object> getBeanFormCacheRowSet(Class<?> clazz, CachedRowSet crs)
    {

        List<Object> result = new ArrayList<Object>();
        try
        {
            ResultSetMetaData md = crs.getMetaData();
            int columnCount = md.getColumnCount();
            Object o = null;
            while (crs.next())
            {
                o = clazz.newInstance();
                for (int i = 1; i <= columnCount; i++)
                {
                    if (crs.getObject(i) == null)
                    {
                        continue;
                    }
                    md.getColumnType(i);
                    String className = md.getColumnClassName(i);
                    if ("java.sql.Timestamp".equals(className) || "java.sql.Date".equals(className))
                    {
                        className = "java.util.Date";
                    }
                    else if ("java.sql.Time".equals(className))
                    {
                        className = "java.lang.String";
                    }
                    else if ("java.lang.Byte".equals(className) || "java.lang.Short".equals(className))
                    {
                        className = "java.lang.Integer";
                    }
                    String methodName = "set" + md.getColumnName(i).substring(0, 1).toUpperCase()
                                        + md.getColumnName(i).substring(1);
                    try
                    {
                        clazz.getMethod(methodName, Class.forName(className)).invoke(o, crs.getObject(i));
                    }
                    catch (NoSuchMethodException e)
                    {
                        LOG.warning("特殊类型字段导致表字段与JavaBean属性不对应！没有找到参数类型是[" + className + "]的SETER方法：" + methodName);
                        continue;
                    }
                    // System.out.println("className : " + className +" \tmethodName : " + methodName);
                }
                result.add(o);
            }
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
        return result;
    }
}