| 基于J2EE架构的电子商务网站实例解析 |
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| 来源:天极yesky 作者: 加入时间：2006-12-8 访问次数:21 [大 中 小] |
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它处理客户程序登陆数据，并配置一些存取数据库的参数，比如缓冲池等。代码示范为：
public void applyLogin() {
//配置数据库访问参数
DatabaseLogin login = new DatabaseLogin();
login.usePlatform(new oracle.toplink.oraclespecific.Oracle9Platform());
login.setDriverClassName("oracle.jdbc.driver.OracleDriver"); login.setConnectionString(ApplicationConfiguration.get(ConfigurationConstants.DB_CON_STR)); login.setUserName(ApplicationConfiguration.get(ConfigurationConstants.DB_USER)); login.setPassword(ApplicationConfiguration.get(ConfigurationConstants.DB_ENCRYPTED_PASSWORD));
// 设置数据库参数
login.setUsesNativeSequencing(true);
login.setSequencePreallocationSize(1);
login.setShouldBindAllParameters(false);
login.setShouldCacheAllStatements(false);
login.setUsesByteArrayBinding(true);
login.setUsesStringBinding(false);
if (login.shouldUseByteArrayBinding()) { // Can only be used with binding.
login.setUsesStreamsForBinding(false);
}
login.setShouldForceFieldNamesToUpperCase(false);
login.setShouldOptimizeDataConversion(true);
login.setShouldTrimStrings(true);
login.setUsesBatchWriting(false);
if (login.shouldUseBatchWriting()) { // Can only be used with batch writing.
login.setUsesJDBCBatchWriting(true);
}
login.setUsesExternalConnectionPooling(false);
login.setUsesExternalTransactionController(false);
setLogin(login);
} |
·建立映射关系
Toplink通过类似于builXXXDescriptor方法来建立Java对象与数据库表字段之间的对应关系，示范代码如下：
public Descriptor buildAccountDescriptor() {
Descriptor descriptor = new Descriptor();
descriptor.descriptorIsAggregate();
descriptor.setJavaClass(com.routease.db.vo.user.Account.class);
descriptor.setAlias("Account");
// Mappings.
//建立Account 对象的deposit属性与数据库表的DEPOSIT字段的对应关系
DirectToFieldMapping depositMapping = new DirectToFieldMapping();
depositMapping.setAttributeName("deposit");
depositMapping.setFieldName("DEPOSIT");
descriptor.addMapping(depositMapping);
…
return descriptor;
} |
3． 定制后台Action
根据MVC的精神，View和Model设计好之后应该是将开发重点转移到控制器的开发上。控制器是根据用户行为进行响应的处理模块，比如用户通过首页的搜索条对服务信息进行检索，这时，web服务中的SearchToTradeEntityAction（对应SearchToTradeEntityAction.java文件）会对用户这一动作进行处理。以下对这一Action进行详细分析：
package com.routease.action.totradeentity;
import java.util.Collection;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.beanutils.PropertyUtils;
import org.apache.commons.lang.StringUtils;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import com.routease.action.PagingAction;
import com.routease.action.helper.UserHelper;
import com.routease.db.dao.DataSource;
import com.routease.db.dao.totradeentity.SearchingCriteria;
import com.routease.db.dao.totradeentity.ToTradeEntityDAO;
import com.routease.db.util.Constants;
import com.routease.db.util.Page;
public class SearchToTradeEntityAction extends PagingAction {
public SearchToTradeEntityAction()
{
super();
}
// executeWithDataSource方法为该Action默认执行的方法
public ActionForward executeWithDataSource(ActionMapping actionMapping, ActionForm actionForm, HttpServletRequest request, HttpServletResponse response, DataSource ds) throws Exception {
//首先接受用户提交的表单数据
String objective = (String) PropertyUtils.getSimpleProperty(actionForm, "objective");
String keyWords = (String) PropertyUtils.getSimpleProperty(actionForm, "keyWords");
String keyWordsRange = (String) PropertyUtils.getSimpleProperty(actionForm, "keyWordsRange");
if (StringUtils.isEmpty(keyWordsRange)) {
keyWordsRange = SearchingCriteria.KEY_WORDS_RANGE_NAME;
}
String industryLevel1 = (String) PropertyUtils.getSimpleProperty(actionForm, "industryLevel1");
String industryLevel2 = (String) PropertyUtils.getSimpleProperty(actionForm, "industryLevel2");
String startingPrice = (String) PropertyUtils.getSimpleProperty(actionForm, "startingPrice");
String endingPrice = (String) PropertyUtils.getSimpleProperty(actionForm, "endingPrice");
String city = (String) PropertyUtils.getSimpleProperty(actionForm, "city");
String province = (String) PropertyUtils.getSimpleProperty(actionForm, "province");
String startNoStr = (String) PropertyUtils.getSimpleProperty(actionForm, "startNumber");
String lengthStr = (String) PropertyUtils.getSimpleProperty(actionForm, "length");
if (StringUtils.isEmpty(startNoStr)) {
startNoStr = "1";
}
//根据用户提交的数据，创建查询表达式对象SC
int startNumber = Integer.parseInt(startNoStr);
int length = UserHelper.getPagingLength(ds, request);
ToTradeEntityDAO serviceDAO = new ToTradeEntityDAO(ds);
SearchingCriteria sc = new SearchingCriteria();
sc.setCity(city);
sc.setProvince(province);
sc.setEndingPrice(endingPrice);
sc.setIndustryLevel1(industryLevel1);
sc.setIndustryLevel2(industryLevel2);
sc.setKeyWords(keyWords);
sc.setKeyWordsRange(keyWordsRange);
sc.setObjective(objective);
sc.setStartingPrice(startingPrice);
if (Constants.IS_TEST) {
System.out.println("start of page:" + startNumber);
}
//提交查询对象SC,并获得查询结果集，将其结果集放入Request对象中，便于返回
Page result = serviceDAO.searchToTradeEntities(sc, startNumber, length);
Collection industries = serviceDAO.findIndustryDistribution(sc);
result.setSizePerPage(length);
request.setAttribute(Constants.TO_TRADE_ENTITY, result);
request.setAttribute("MY_INDUSTRIES",industries);
request.setAttribute("MY_PAGE", result);
//业务逻辑处理完毕之后，返回成功页面
return actionMapping.findForward("SUCCESS_PAGE");
}
} |
SearchToTradeEntityAction是一个典型的Action，由前面注解不难看出，一般Action分为三部分：
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