笔记如下
1.单个删除
4.png
- web层(DeleteOneCustomersServlet)
//获得id
String id = request.getParameter("id");
//调用业务层去删除,将id带过去
CustomerService cs = new CustomerService();
cs.deleteOneCustomerById(id);
//删除成功后再次查询 ---- 重定向到查询页面
response.sendRedirect(request.getContextPath() + "/findall");
- 业务层(CustomerService)
//根据客户的id好去删除信息
public void deleteOneCustomerById(String id) {
// TODO Auto-generated method stub
cdao.deleteOneById(id);
}
- dao层(CustomerDaoImpl)
//单个删除
/* (non-Javadoc)
* @see com.chen.customers.dao.CustomerDao#deleteOneById(java.lang.String)
*/
@Override
public void deleteOneById(String id) {
// TODO Auto-generated method stub
QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
try {
runner.update("delete from customers where id=?", new Object[] {id});
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
2.全删除
- jsp
<script type="text/javascript">
//点击是否勾选全部的js代码
function checkAllStatus() {
//拿到最上面的
var checkBtn = document.getElementById("checked");
//alert(checkBtn.checked);
//拿到所有name为ids的input
var ids = document.getElementsByName("ids");
for (var i = 0; i < ids.length; i++) {
ids[i].checked = checkBtn.checked;
}
</script>
<table border="1" align="center" width="100%">
<tr>
<th>
设置状态<input type="checkbox" name="checkBtn" id="checked" onclick="checkAllStatus();">
</th>
<th>客户姓名</th>
<th>客户性别</th>
<th>客户生日</th>
<th>客户邮箱</th>
<th>客户手机</th>
<th>客户爱好</th>
<th>客户类型</th>
<th>客户描述</th>
<th>操作</th>
</tr>
<c:forEach items="${customers}" var="customer">
<tr>
<td>
<input type="checkbox" name="ids" value="${customer.id}">
</td>
<td>${customer.name}</td>
<td>${customer.gender}</td>
<td>${customer.birthday}</td>
<td>${customer.email}</td>
<td>${customer.cellphone}</td>
<td>${customer.preference}</td>
<td>${customer.type}</td>
<td>${customer.description}</td>
<td>
<a href="javascript:void(0)" onclick="confrimDel('${customer.id}')">删除</a>
<a href="${pageContext.request.contextPath }/getonebyid?id=${customer.id}" >更新</a>
</td>
</tr>
</c:forEach>
</table>
4.png
- web层(DeteleBatchServlet)
//获得批量id
String[] ids = request.getParameterValues("ids");
ThreadLocal t;
//传递ids给业务层,去删除
CustomerService cs = new CustomerService();
cs.deleteBatch(ids);
//重定向
response.sendRedirect(request.getContextPath() + "/findall");
- 业务层(CustomerService)
//批量删除:批量删除,要么全部失败,要么全部成功-----事务
//解决数据耦合 ----- ThreadLocal类
public void deleteBatch(String[] ids) {
// TODO Auto-generated method stub
try {
//开启事务 ----- set(conn)(ThreadLocal类)
TransactionUtil.startTransaction();
for (String id : ids) {
//不能用cdao.deleteOneById(id)
cdao.deleteOneByIdInTransaction(id);
}
// //提交事务
// conn.commit();
TransactionUtil.commit();
} catch (Exception e) {
//有异常就回滚
TransactionUtil.rollback();
}finally {
//释放资源
TransactionUtil.relase();
}
}
- dao层(CustomerDaoImpl)
//在事务中的单个删除
@Override
public void deleteOneByIdInTransaction(String id) throws SQLException {
// TODO Auto-generated method stub
QueryRunner runner = new QueryRunner();
runner.update(TransactionUtil.getConnection(),"delete from customers where id=?", new Object[] {id});
}
- 工具类(TransactionUtil)
//把得到连接及事务有关的方法写到此类中
public class TransactionUtil {
// 内部是维护了 一个 map , 这个map 的key 始终 都是 当前 的线程
private static ThreadLocal<Connection> tl = new ThreadLocal<Connection>();
private static DataSource ds = JdbcUtils.getDataSource();
public static DataSource getDataSource(){
return ds;
}
// 这里, 获得一个 connection 对象
public static Connection getConnection(){
try {
Connection conn = tl.get();
if(conn==null){
//从数据连接池 中 取 一个连接 出来
conn = ds.getConnection();
//将 取出来 connection 放到 tl中去
tl.set(conn);
}
return conn;
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
// 开启 事务
// 结果 就是 返回了 一个 connection对象, 并且 将 返回的 connection放到了 threadlocal中 ,
public static void startTransaction(){
try {
Connection conn = tl.get();
if(conn==null){
conn = getConnection();
// tl.set(conn);
}
conn.setAutoCommit(false);
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
public static void rollback(){
try {
Connection conn = tl.get();
if(conn==null){
conn = getConnection();
// tl.set(conn);
}
conn.rollback();
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
public static void commit(){
try {
Connection conn = tl.get();
if(conn==null){
conn = getConnection();
// tl.set(conn);
}
conn.commit();
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
public static void relase(){
try {
Connection conn = tl.get();
if(conn!=null){
conn.close();
tl.remove();
}
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
}
