Java Ajax调用在servlet中不起作用？
我试图从JSP向Servlet发出Ajax调用，然后从Servlet获取数据并将其嵌入html视图。目前，在ajax调用之后，数据甚至没有添加到我的标记中。我可能做错了什么？有更好的方法吗？非常感谢您的任何建议 HomeServlet.java 包com.exampleJava Ajax调用在servlet中不起作用？,java,jquery,ajax,jsp,servlets,Java,Jquery,Ajax,Jsp,Servlets,我试图从JSP向Servlet发出Ajax调用，然后从Servlet获取数据并将其嵌入html视图。目前，在ajax调用之后，数据甚至没有添加到我的标记中。我可能做错了什么？有更好的方法吗？非常感谢您的任何建议 HomeServlet.java 包com.example import java.io.IOException; import java.io.PrintWriter; import java.sql.Connection; import java.sql.DriverManager;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.json.JSONArray;
import com.google.gson.Gson;
/**
* Servlet implementation class Home
*/
@WebServlet("/HomeServlet")
public class HomeServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public HomeServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
Map<String, String> options = new LinkedHashMap<>();
String text = "some text";
PrintWriter out = response.getWriter();
response.setContentType("text/html");
out.println("<html><body>");
try {
Class.forName("com.mysql.jdbc.Driver");
Connection con= (Connection) DriverManager.getConnection("jdbc:mysql://localhost/apiprovider","root","");
Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery("select * from apiinfo");
// out.println("<table border=1 width=50% height=50%>");
// out.println("<tr><th>EmpId</th><th>EmpName</th><th>Salary</th><tr>");
while (rs.next()) {
String n = rs.getString("apiname");
String nm = rs.getString("apiendpoint");
options.put("value1", n);
options.put("value2", nm);
String json = new Gson().toJson(options);
response.setContentType("application/json");
response.setCharacterEncoding("UTF-8");
response.getWriter().write(json);
// out.println("<tr><td>" + n + "</td><td>" + nm + "</td><td>" + s + "</td></tr>");
}
// out.println("</table>");
// out.println("</html></body>");
con.close();
}
catch (Exception e) {
out.println("error");
}
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
//doGet(request, response);
response.setContentType("text/html");
PrintWriter out= response.getWriter();
String n = request.getParameter("apiname");
String p = request.getParameter("apiendpoint");
String e = request.getParameter("apiversion");
String c = request.getParameter("source");
try
{
Class.forName("com.mysql.jdbc.Driver");
System.out.println("driver loaded");
System.out.println("Driver is loaded");
Connection con= (Connection) DriverManager.getConnection("jdbc:mysql://localhost/apiprovider","root","");
System.out.println("Connection created");
PreparedStatement ps= ((java.sql.Connection) con).prepareStatement("insert into apiinfo(apiname,apiendpoint,apiversion,accessibility) values (?,?,?,?)");
ps.setString(1,n);
ps.setString(2,p);
ps.setString(3, e);
ps.setString(4,c);
ps.execute();
out.close();
System.out.println("Inserted");
}
catch(Exception e1)
{
System.out.println(e1);
}
}
}
尝试在浏览器上调试，看看是否从ajax调用中获取数据。是否检查是否找到servlet？
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<div id="ajaxresponse">
</div>
<form>
API Name:<br>
<input type="text" id = "apiname" name="apiname">
API ENDPOINT:<br>
<input type="text" id ="apiendpoint" name="apiendpoint">
<br>
API VERSION:<br>
<input type="text" id="apiversion" name="apiversion">
ACCESSIBLE:<br>
<input type="checkbox" name="source" value="internet"> Internet<br>
<input type="checkbox" name="source" value="vpn"> VPN<br>
<!--
<br><br>
<input type="submit" formaction="Home" method="post" value="Submit"> -->
<br>
<input type="submit" id="check" name="check" value="Check">
</form>
<script src="https://code.jquery.com/jquery-3.2.1.min.js"></script>
<script type="text/javascript">
$(document).on("click", "#check", function() { // When HTML DOM "click" event is invoked on element with ID "somebutton", execute the following function...
console.log("I was clicked");
$.get("HomeServlet", function(responseText) {
// Execute Ajax GET request on URL of "someservlet" and execute the following function with Ajax response text...
var $select = $("#ajaxresponse"); // Locate HTML DOM element with ID "someselect".
$select.find("option").remove(); // Find all child elements with tag name "option" and remove them (just to prevent duplicate options when button is pressed again).
$.each(responseJson, function(key, value) {
// Iterate over the JSON object.
$("<option>").val(key).text(value).appendTo($select); // Create HTML <option> element, set its value with currently iterated key and its text content with currently iterated item and finally append it to the <select>.
}); // Locate HTML DOM element with ID "somediv" and set its text content with the response text.
});
});
</script>
</body>
</html>
http://localhost:8080/TestApplication/Home.jsp?apiname=&apiendpoint=&apiversion=&check=Check