如何通过单击JSP页面中的超链接或按钮将当前项传递给Java方法?
我有一个HTML表,其中包含从该表中显示的数据库中获取的行。我希望用户能够通过单击每行旁边的删除超链接或按钮来删除一行 当用户单击每个删除超链接或按钮时,如何调用页面上的JSP函数,以便从数据库中删除该行的条目?如何通过单击JSP页面中的超链接或按钮将当前项传递给Java方法?,jsp,Jsp,我有一个HTML表,其中包含从该表中显示的数据库中获取的行。我希望用户能够通过单击每行旁边的删除超链接或按钮来删除一行 当用户单击每个删除超链接或按钮时,如何调用页面上的JSP函数,以便从数据库中删除该行的条目?或标记必须调用JSP函数的具体内容是什么 请注意,我需要调用一个JSP函数,而不是JavaScript函数。最简单的方法是:让链接指向一个JSP页面,并将行ID作为参数传递: <a href="delete.jsp?id=1">delete</a&g
或
标记必须调用JSP函数的具体内容是什么
请注意,我需要调用一个JSP函数,而不是JavaScript函数。最简单的方法是:让链接指向一个JSP页面,并将行ID作为参数传递:
<a href="delete.jsp?id=1">delete</a>
然而,这是一个相当不错的说法(这仍然是一个轻描淡写的说法),原因有两个:
和
来执行删除操作。但是,您可以使用CSS将按钮样式设置为链接。只需预加载项目以预填充编辑表单的编辑链接就可以安全地获得
东西)将业务逻辑(您所称的函数)放入JSP中。您应该使用Servlet来控制、预处理和后处理HTTP请求
Product
为例
public class Product {
private Long id;
private String name;
private String description;
private BigDecimal price;
// Add/generate public getters and setters.
}
然后是JSP文件,它使用(只需插入/WEB-INF/lib
即可安装)在表格中显示产品,每行有一个编辑链接和一个删除按钮:
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>
...
<form action="products" method="post">
<table>
<c:forEach items="${products}" var="product">
<tr>
<td><c:out value="${fn:escapeXml(product.name)}" /></td>
<td><c:out value="${product.description}" /></td>
<td><fmt:formatNumber value="${product.price}" type="currency" currencyCode="USD" /></td>
<td><a href="${pageContext.request.contextPath}/product?edit=${product.id}">edit</a></td>
<td><button type="submit" name="delete" value="${product.id}">delete</button></td>
</tr>
</c:forEach>
</table>
<a href="${pageContext.request.contextPath}/product">add</a>
</form>
下面是位于/WEB-INF/product.jsp
的添加/编辑表单的外观:
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
...
<form action="product" method="post">
<label for="name">Name</label>
<input id="name" name="name" value="${fn:escapeXml(product.name)}" />
<br/>
<label for="description">Description</label>
<input id="description" name="description" value="${fn:escapeXml(product.description)}" />
<br/>
<label for="price">Price</label>
<input id="price" name="price" value="${fn:escapeXml(product.price)}" />
<br/>
<button type="submit" name="save" value="${product.id}">save</button>
</form>
部署并运行它。你可以在旁边打开桌子
另请参见:
- (还包含一个验证示例)
@WebServlet("/products")
public class ProductsServlet extends HttpServlet {
private ProductDAO productDAO; // EJB, plain DAO, etc.
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
List<Product> products = productDAO.list();
request.setAttribute("products", products); // Will be available as ${products} in JSP.
request.getRequestDispatcher("/WEB-INF/products.jsp").forward(request, response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String delete = request.getParameter("delete");
if (delete != null) { // Is the delete button pressed?
productDAO.delete(Long.valueOf(delete));
}
response.sendRedirect(request.getContextPath() + "/products"); // Refresh page with table.
}
}
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
...
<form action="product" method="post">
<label for="name">Name</label>
<input id="name" name="name" value="${fn:escapeXml(product.name)}" />
<br/>
<label for="description">Description</label>
<input id="description" name="description" value="${fn:escapeXml(product.description)}" />
<br/>
<label for="price">Price</label>
<input id="price" name="price" value="${fn:escapeXml(product.price)}" />
<br/>
<button type="submit" name="save" value="${product.id}">save</button>
</form>
@WebServlet("/product")
public class ProductServlet extends HttpServlet {
private ProductDAO productDAO; // EJB, plain DAO, etc.
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String edit = request.getParameter("edit");
if (edit != null) { // Is the edit link clicked?
Product product = productDAO.find(Long.valueOf(delete));
request.setAttribute("product", product); // Will be available as ${product} in JSP.
}
request.getRequestDispatcher("/WEB-INF/product.jsp").forward(request, response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String save = request.getParameter("save");
if (save != null) { // Is the save button pressed? (note: if empty then no product ID was supplied, which means that it's "add product".
Product product = (save.isEmpty()) ? new Product() : productDAO.find(Long.valueOf(save));
product.setName(request.getParameter("name"));
product.setDescription(request.getParameter("description"));
product.setPrice(new BigDecimal(request.getParameter("price")));
productDAO.save(product);
}
response.sendRedirect(request.getContextPath() + "/products"); // Go to page with table.
}
}