我屏蔽掉那里则能存到数据库,但是是null,已经填了东西上去了,如果不屏蔽的话输出“书名不能为空”,没有报错!System.out.println(sql);了一下是输出insert into book(bookname,bookauthor,bookpress,bookedition,booklocation) values('null','null',null,'null','null'),这要怎么解决,求大佬帮忙!
//添加书本(控制部分)
public boolean addBook(String bookname, String bookauthor, String bookpress,String bookedition,String booklocation)
{
Connection conn = null;
Statement stmt = null;
try {
conn = Database.getConnection();
stmt = conn.createStatement();
String sql = "insert into book(bookname,bookauthor,bookpress,bookedition,booklocation) "
+ "values('"+bookname+"','"+bookauthor+"',"+bookpress+",'"+bookedition+"','"+booklocation+"')";
//System.out.println(sql);
stmt.execute(sql);
return true;
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return false;
} finally {
Database.close(conn, stmt);
}
}
//用的是servlet的doget和dopost,下面为servlet部分
String bookname = request.getParameter("bookname");//初始化图书的各个字段
String bookauthor = request.getParameter("bookauthor");
String bookpress = request.getParameter("bookpress");
String bookedition = request.getParameter("bookedition");
String booklocation = request.getParameter("booklocation");
// if(bookname==null||bookname.trim().isEmpty()){
// request.setAttribute("msg", "书名不能为空");
// request.getRequestDispatcher("/addbook.jsp").forward(request, response);
// return;
// }
// if(bookauthor==null||bookauthor.trim().isEmpty()){
// request.setAttribute("msg", "作者不能为空");
// request.getRequestDispatcher("/addbook.jsp").forward(request, response);
// return;
// }
// if(bookpress==null||bookpress.trim().isEmpty()){
// request.setAttribute("msg", "出版社不能为空");
// request.getRequestDispatcher("/addbook.jsp").forward(request, response);
// return;
// }
// if(bookedition==null||bookedition.trim().isEmpty()){
// request.setAttribute("msg", "版本不能为空");
// request.getRequestDispatcher("/addbook.jsp").forward(request, response);
// return;
// }
// if(booklocation==null||booklocation.trim().isEmpty()){
// request.setAttribute("msg", "出版存放位置不能为空");
// request.getRequestDispatcher("/addbook.jsp").forward(request, response);
// return;
// }
Operator operate = new Operator();
boolean isSuccess = operate.addBook(bookname, bookauthor, bookpress, bookedition,booklocation);
if(isSuccess){
request.setAttribute("msg", "增加成功");
request.getRequestDispatcher("/addbook.jsp").forward(request, response);
return;
}else{
request.setAttribute("msg", "增加失败");
request.getRequestDispatcher("/addbook.jsp").forward(request, response);
return;
}
//下面是jsp部分
<form action="AddBookServlet" method="post" enctype="multipart/form-data">
<div>
<input type="text" name="bookname" placeholder="请输入书名(如:三国演义)"></div>
<div>
<input type="text" name="bookauthor" placeholder="请输入作者(如:张三)"></div>
<div>
<input type="text" name="bookpress" placeholder="请输入出版社(如:中山大学出版社)"></div>
<div>
<input type="text" name="bookedition" placeholder="请输入版本(如:第一版)"></div>
<div>
<input type="text" name="booklocation" placeholder="请输入存放位置(如:1楼101室2019)"></div>
<!-- <div>
<a href="javascript:;" class="a-upload">点击这里上传文件(.txt文件)
<input type="file" name="file" id="file">
</a></div> -->
<div>
<input type="submit" value="增加图书" id="addbook">
</div>
<div>
<a href="welcome.jsp" id="back">返回菜单</a></div></br>
</form>
<font color="red" size="2"> ${msg }</font>