我的AJAX函数如果json数组中有1个以上的元素，则显示列表实际上，我想从组织中搜索候选数据并将其打印到jsp页面。但是，当搜索结果来自一个组织的一个以上候选者时，则工作正常，但在json数组中仅包含一个元素时，效果不佳。
$("#searchbtn").click(function(event) {
$('#loadingarea').show();
arr.length = 0;
names = "";
total_fees = 0;
$("#paymentForm").hide();
$("#idbox").val("");
$("#name").val("");
$("#totalcostbox").val("");
$("#countrytable").empty();
var org_name = $("#org_name").val();
jQuery.get('PaymentCandidates',
{org_name:org_name}, function(responseJson)
{
console.log("HI Response is coming!!! :::"+responseJson);
var str = '<tr>\n' +
'<th>Select</th>\n' +
'<th>Name</th>\n' +
'<th>Stream</th>\n' +
'<th>Phase</th>\n' +
'<th>ExamType</th>\n' +
'<th>ExamDate</th>\n' +
'<th>Training Date (from)</th>\n' +
'<th>Training Date (to)</th>\n' +
'<th>Fees</th>\n' +
'<th>View</th>\n'+
'</tr>';
console.log("Collecting reponse from PaymentCandidates::::");
if(responseJson.length>0) {
$("#loadingarea").hide();
console.log("Total Entries::::" + responseJson.length);
//$("#countrytable").empty();
var table1 = $("#countrytable");
if (responseJson.length===1) {
$.each(responseJson[0], function (key, value) {
var json = JSON.parse(JSON.stringify(responseJson.toString()));
examtype = (value['examtype']);
stream = (value['stream']);
selected_name = (value['name'].toString());
if (examtype === "Exam") {
cost = 1000;
} else if (examtype === "Training") {
if (stream === "PCB") {
cost = 20000;
} else {
cost = 60000;
}
} else {
cost = 0;
}
str += '<tr><td style="font-size: 25px"><input name=' + selected_name + ' type="checkbox" id=' + (value['id']) + ' value=' + cost + ' onchange="onCheckBoxChanged(this.id,this.value,this.name)"></td>';
str += '<td>' + (value['name']) + '</td>';
str += '<td>' + (value['stream']) + '</td>';
str += '<td>' + (value['phase']) + '</td>';
str += '<td>' + (value['examtype']) + '</td>';
str += '<td>' + (value['examdate']) + '</td>';
str += '<td>' + (value['training_from_date']) + '</td>';
str += '<td>' + (value['training_to_date']) + '</td>';
str += '<td>' + cost + '</td>';
str += '<td> <a class="button view" target="_blank" href=viewDetailedCandidate.jsp?' + (value['id']) + '>View Candidate Details</a></td></tr>';
$("#countrytable").append(str);
});
} else {
$("#loadingarea").hide();
$.each(responseJson, function (key, value) {
var json = JSON.parse(JSON.stringify(responseJson.toString()));
depositbal=(value['balance']);
if(depositbal>0){
$("#usethisbal").show();
}
else{
$("#usethisbal").hide();
}
$("#balancebox").val(depositbal);
examtype = (value['examtype']);
stream = (value['stream']);
selected_name = (value['name'].toString());
if (examtype === "Exam") {
cost = 1000;
} else if (examtype === "Training") {
if (stream === "PCB") {
cost = 20000;
} else {
cost = 60000;
}
} else {
cost = 0;
}
str += '<tr><td style="font-size: 25px"><input name=' + selected_name + ' type="checkbox" id=' + (value['id']) + ' value=' + cost + ' onchange="onCheckBoxChanged(this.id,this.value,this.name)"></td>';
str += '<td>' + (value['name']) + '</td>';
str += '<td>' + (value['stream']) + '</td>';
str += '<td>' + (value['phase']) + '</td>';
str += '<td>' + (value['examtype']) + '</td>';
str += '<td>' + (value['examdate']) + '</td>';
str += '<td>' + (value['training_from_date']) + '</td>';
str += '<td>' + (value['training_to_date']) + '</td>';
str += '<td>' + cost + '</td>';
str += '<td> <a class="button view" target="_blank" href=viewDetailedCandidate.jsp?' + (value['id']) + '>View Candidate Details</a></td></tr>';
});
$("#countrytable").append(str);
}
}
else{
console.log("JSON Array Fetch Null....");
}
});
$("#tablediv").show();
});
});
它也不会在控制台中打印任何内容
这是我的servlet
import com.google.gson.Gson;
import com.google.gson.Gson;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.*;
import java.util.ArrayList;
@WebServlet("/PaymentCandidates")
public class PaymentCandidates extends HttpServlet {
Gson gson = new Gson();
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
String org_name=req.getParameter("org_name");
System.out.println("ORG_NAME:"+org_name);
//fetch Candidates from db
ArrayList<Candidates> candidatesList = new ArrayList<>();
PrintWriter pw=resp.getWriter();
try{
Class.forName("com.mysql.jdbc.Driver");
Connection connCandidate = null,connDeposit=null;
System.out.println(":::CONNECTING TO CANDIDATES DB::::");
connCandidate = DriverManager.getConnection("jdbc:mysql://localhost:3306/candidate_db", "root", "");
System.out.println("Connected to Candidates DB for PAYMENT::::$$$$$");
Statement stmt=connCandidate.createStatement();
ResultSet rs = stmt.executeQuery("SELECT * FROM `candidate_details` WHERE isPayment_received=\"Not Yet\" ");
while(rs.next()){
if(rs.getString(6).toLowerCase().contains(org_name.toLowerCase())) {
Candidates cd = new Candidates();
System.out.println("NAME:" + rs.getString(2));
connDeposit = DriverManager.getConnection("jdbc:mysql://localhost:3306/deposit_db", "root", "");
Statement st1=connDeposit.createStatement();
ResultSet resultSet=st1.executeQuery("SELECT * FROM deposit_details;");
while(resultSet.next()) {
if (resultSet.getString(1).equals(rs.getString(5))) {
cd.setBalance(resultSet.getString(2));
}
}
if(cd.getBalance()==null){
cd.setBalance("0");
}
resultSet.close();
st1.close();
connDeposit.close();
cd.setId(rs.getString(1));
cd.setName(rs.getString(2));
cd.setStream(rs.getString(7));
cd.setPhase(rs.getString(8));
cd.setExamtype(rs.getString(15));
cd.setExamdate(rs.getString(17));
cd.setTrainingfromdate(rs.getString(18));
cd.setTrainingtodate(rs.getString(19));
candidatesList.add(cd);
}
}
if(!(candidatesList.size() > 1)){
pw.println("<script type=\"text/javascript\">");
pw.println("alert('No Candidates Found');");
pw.println("location='fillPayment.jsp';");
pw.println("</script>");
}
System.out.println("GSON Done:::");
String jsonString=gson.toJson(candidatesList);
System.out.println("JSON ELEMENT DONE::");
System.out.println("JSON ARRAY:::"+jsonString);
resp.setContentType("application/json");
resp.getWriter().write(jsonString);
System.out.println("JSON ARRAY WRITTEN!!!");
}
catch(SQLException | ClassNotFoundException ce){
pw.println("-------ERROR IN PROCESSING PAYMENT-----");
pw.println("Error is:"+ ce.getMessage());
}
}
}
***Servlet Output***
ORG_NAME:Evil Corporation
:::CONNECTING TO CANDIDATES DB::::
Connected to Candidates DB for PAYMENT::::$$$$$
NAME:Kaival Patel
GSON Done:::
JSON ELEMENT DONE::
JSON ARRAY:::
[{"id":"1","name":"KaivalPatel",
"stream":"Ahmedabad","phase":"21","examtype":"8","examdate":"Exam",
"training_from_date":"No","training_to_date":"-","balance":"0"}]
JSON ARRAY WRITTEN!!!
由于json array中只有一个元素，所以您不需要循环通过$.each循环，您可以使用responseJson[0]['keyname']直接访问所有元素。此外，当您在[[ C0]循环所有值都为responseJson[0]，因为jquery无法识别$.each。相反，您可以执行以下操作（我已删除了所有不相关的代码）：
undefinedkeys