Java 未捕获类型错误:非法调用
我正在尝试使用Ajax、Servlet和HTML从数据库中删除用户。当我提交数据时,会发生非法调用。我认为连接或SQL语句不会有任何问题 delete.htmlJava 未捕获类型错误:非法调用,java,javascript,jquery,servlets,Java,Javascript,Jquery,Servlets,我正在尝试使用Ajax、Servlet和HTML从数据库中删除用户。当我提交数据时,会发生非法调用。我认为连接或SQL语句不会有任何问题 delete.html <input type="text" id="delete"> <input type="submit" onclick="deleteUSer()" value="Delete"> Delete.java servlet protected void processRequest(HttpServletReq
<input type="text" id="delete">
<input type="submit" onclick="deleteUSer()" value="Delete">
Delete.java servlet
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
PrintWriter out = null;
DBUtils dbutils = null;
Connection conn = null;
try{
String username = request.getParameter("username");
dbutils = new DerbyUtils();
conn = dbutils.getConnection();
DeleteDAO dao = new DeleteDAO(conn);
dao.deleteUser(username);
RequestDispatcher dispatcher =
getServletContext().getRequestDispatcher("/index.html");
dispatcher.forward(request, response);
}
DeleteDAO.java
public void deleteUser(String username) throws SQLException{
try{
String sql = "delete from users where username='"+username+"'";
PreparedStatement ps = this.conn.prepareStatement(sql);
ps.executeQuery();
您正在发送的html文档不是用户名 试试这个--
函数deleteUSer(){
var username=document.getElementById(“删除”);
变量参数={
用户名:username.value
}
$.post(“删除”,参数,函数(数据){}
)
}
如果试图执行可用于HTTP请求的“delete”命令,则需要使用$.ajax
,而不是$.post
要引用文档():
这是一个速记Ajax函数,相当于:
$.ajax({
type: "POST",
url: url,
data: data,
success: success,
dataType: dataType
});
如果您试图执行“删除”,您可能希望执行以下操作:
var dataObj = {
'username': document.getElementById("delete").value;
}
$.ajax({
type:"DELETE",
data: dataObj,
url: 'url/to/your/servlet'
});
您可能还希望在其中包含一个数据类型,但对于本例,jquery可以解决这个问题
$.ajax({
type: "POST",
url: url,
data: data,
success: success,
dataType: dataType
});
var dataObj = {
'username': document.getElementById("delete").value;
}
$.ajax({
type:"DELETE",
data: dataObj,
url: 'url/to/your/servlet'
});