在Struts数据库应用程序中实现记录的删除、更新及链接的步骤
如何在Struts 数据库应用程序中实现记录的删除、更新及链接(续)
dbListDAO.java文件：
这里定义一个DAO类，用于实现数据加的查找、删除、更新、添加及生成分页字符串等功能。getPagestr(int ipage)函数用于生成分页字符串，int ipage参数用于转递当前页码。findSQL(String sql,int ipage)函数用于查找数据库数据，String sql参数用于转递SQL查询语句字符串，int ipage参数用于转递当前页码。
。。。。。。。。。。(省略)
public class dbListDAO {
与记录更新、删除和添加无关的代码省略。
public void create(dbList m_dbList) throws SQLException {
PreparedStatement ps = null;
//<createSQL>
String sql = "INSERT INTO dbo.Test VALUES (?,?,?)";
//</createSQL>
try {
if (con.isClosed()) {
throw new IllegalStateException("error.unexpected");
}
//用SQL Server请加入下行:
con.setAutoCommit(true);
//SQL Server
ps = con.prepareStatement(sql);
//<create>
ps.setInt(1,m_dbList.get序号());
ps.setString(2,m_dbList.get姓名());
ps.setString(3,m_dbList.get备注());
//</create>
if (ps.executeUpdate() != 1) {
throw new SQLException ("error.create.dbList");
}
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException("error.unexpected");
} finally {
try {
if (ps != null)
ps.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException("error.unexpected");
}
}
}
public void update(dbList m_dbList,String keyID) {
PreparedStatement ps = null;
//<updateSQL>
String sql = "UPDATE dbo.Test SET 序号 = ?,姓名 = ?,备注 = ? WHERE 序号 = ?";
//</updateSQL>
try {
if (con.isClosed()) {
throw new IllegalStateException("error.unexpected");
}
//用SQL Server请加入下行:
con.setAutoCommit(true);
//SQL Server
ps = con.prepareStatement(sql);
//<update>
ps.setInt(1,m_dbList.get序号());
ps.setString(2,m_dbList.get姓名());
ps.setString(3,m_dbList.get备注());
//</update>
///////////////
//<updatekeyID>
ps.setInt(4,java.lang.Integer.parseInt(keyID,10));
//</updatekeyID>
if (ps.executeUpdate() != 1) {
throw new SQLException (
"error.removed.dbList");
}
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException("error.unexpected");
} finally {
try {
if (ps != null)
ps.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException("error.unexpected");
}
}
}
public void removeID(String keyID) {
//<removeIDSQL>
String sql="DELETE FROM dbo.Test WHERE ";
sql+="序号";
sql+=" = ?";
//</removeIDSQL>
PreparedStatement ps = null;
try {
if (con.isClosed()) {
throw new IllegalStateException("error.unexpected");
}
//用SQL Server请加入下行:
con.setAutoCommit(true);
//SQL Server
ps = con.prepareStatement(sql);
//<setremovekeyIDdata>
ps.setInt(1,java.lang.Integer.parseInt(keyID,10));
//</setremovekeyIDdata>
if (ps.executeUpdate() != 1) {
throw new SQLException (
"error.removed.dbList");
}
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException("error.unexpected");
} finally {
try {
if (ps != null)
ps.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException("error.unexpected");
}
}
}
与记录更新、删除和添加无关的代码省略。
}
dbListAction.java文件：
。。。。。。。。。。(省略)
public final class dbListAction extends Action
{
// 变量定义：
private Log log = LogFactory.getLog("org.apache.struts.webapp.Example");
private ConnectionPool pool;
public dbListAction() {
pool = ConnectionPool.getInstance();
}
//函数定义：
public ActionForward execute(ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response)
throws Exception
{
// Extract attributes and parameters we will need
Locale locale = getLocale(request);
MessageResources messages = getResources(request);
HttpSession session = request.getSession();
dbListForm m_dbListForm = (dbListForm) form;
Connection con = null;
try
{
con = pool.getConnection();
dbListDAO m_dbListDAO = new dbListDAO(con); //定义DAO对象，用于实现数据库的各种操作
String action=request.getParameter("action"); //动作类型
String search=request.getParameter("search"); //数据库查找方式
String expression=request.getParameter("expression"); //参数，这里用于保存记录（行）的ID数据
if(action==null)action="find";
if(search==null)search="UNsearch";
if(expression==null)expression="";
expression=toChinese(expression); //处理中文问题,实现编码转换
if("delete".equals(action)) //删除记录操作
{
m_dbListDAO.removeID(expression);
}
////////////
if("update".equals(action)||"insert".equals(action)) //更新、添加记录操作
{
dbList m_dbList= new dbList();
//<update>
m_dbList.set序号(m_dbListForm.get序号());
m_dbList.set姓名(m_dbListForm.get姓名());
m_dbList.set备注(m_dbListForm.get备注());
//</update>
if("update".equals(action)) //调用DAO对象更新记录
m_dbListDAO.update(m_dbList,expression);
if("insert".equals(action)) //调用DAO对象添加记录
m_dbListDAO.create(m_dbList);
}
///////////////查找数据库
//<sqlstr>
String sql="SELECT * FROM dbo.Test";
//</sqlstr>
////SQL字符处理
if("search".equals(search))
{
//<search>
sql+=" where ";
sql+="序号";
sql+="=";
if("NULL".equals(expression)||"".equals(expression))
{
sql+=m_dbListForm .get序号();
}
else
{
sql+=expression;
}
sql+="";
//</search>
}
//<分页>
（略）
//</分页>
return mapping.findForward("success");
}
catch (SQLException e)
{
（略）
}
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