我正在编写一个简单的 angularjs - J2EE 应用程序来从 mysql服务器获取数据并显示在html页面上。 我在表单上调用角度函数提交为：
<div id="register_form" ng-controller="MyDiaryLogin">
<form>
<ul>
<li><input type="text" name="firstname" ng-model="user.firstname" /></li>
<li><input type="text" name="lastname" ng-model="user.lastname" /></li>
<li><input type="text" name="email" ng-model="user.email" /></li>
<li><input type="password" name="password" ng-model="user.password" /></li>
<li><input type="password" name="confpass" ng-model="user.confpass" /></li>
<li><input type="text" name="age" ng-model="user.age" /></li>
<li><input type="text" name="occupation" ng-model="user.occupation" /></li>
<li><input type="button" name="register" ng-click="register()" value="REGISTER" /></li>
</ul>
</form>
<p><h2>{{status}}</h2></p>
</div>
{{status}} 这里是来自我的angular script.js的$ scope属性：
mydiary.controller('MyDiaryLogin', function($scope, $http){
$scope.user = {};
$scope.register = function(){
$http({
method: 'POST',
url: 'http://localhost:9091/Angular1/getData',
header: {'Content-Type': 'application/json'},
data: $scope.user
}).success(function(data){
$scope.status = data;
});
};
我已经编写了一个servlet来从数据库中获取数据，但是当我在servlet中的控制台上打印一些文本时，错误就到达了servlet。 当我点击 REGISTER 按钮时，浏览器控制台会显示错误：
POST http://localhost:9091/Angular1/getData 500（内部服务器错误）
并且此错误指向某个angular.js函数的xhr.send(...) lib：
if (responseType) {
try {
xhr.responseType = responseType;
} catch (e) {
// WebKit added support for the json responseType value on 09/03/2013
// https://bugs.webkit.org/show_bug.cgi?id=73648. Versions of Safari prior to 7 are
// known to throw when setting the value "json" as the response type. Other older
// browsers implementing the responseType
//
// The json response type can be ignored if not supported, because JSON payloads are
// parsed on the client-side regardless.
if (responseType !== 'json') {
throw e;
}
}
}
xhr.send(post || null);
}
供您参考我的 servlet类的doPost方法：
protected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException{
try{
System.out.println("CALLING THE METHOD");
Class.forName("com.mysql.jdbc.Driver");
cn = DriverManager.getConnection("jdbc:mysql://localhost/mydiary","root","");
String query = "SELECT * FROM users";
pstmt = cn.prepareStatement(query);
rs = pstmt.executeQuery();
String json = new Gson().toJson(rs);
response.setContentType("text/html");
out = response.getWriter();
out.write(json);
}
catch(Exception e){
e.printStackTrace();
}
try{
try{}
finally{
if(rs!=null)
rs.close();
if(pstmt!=null)
pstmt.close();
if(out!=null)
out.flush();
out.close();
if(cn!=null)
cn.close();
}
}
catch(Exception e1){
e1.printStackTrace();
}
}
请帮我找到问题的根源，我写完整的应用程序代码有什么问题吗？我不确定如何使用angular来显示来自servlet的数据/返回json格式数据？
答案 0 :(得分：0)
为了让您了解如何将结果集转换为JSON，我在此处添加了此类。您可以使用它：jsonArr = ResultSetConverter.convert（result，＆＃34;＆＃34;）;
这是一个非常通用的类，可以处理所有的sql数据类型，所以选择你需要的东西。
import org.json.JSONArray;
import org.json.JSONObject;
import org.json.JSONException;
import java.sql.SQLException;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.Timestamp;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;
public class ResultSetConverter {
public static final Calendar tzUTC = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
public static JSONArray convert( ResultSet rs, String freitextlabel )
throws SQLException, JSONException
{
JSONArray json = new JSONArray();
ResultSetMetaData rsmd = rs.getMetaData();
while(rs.next()) {
int numColumns = rsmd.getColumnCount();
JSONObject obj = new JSONObject();
for (int i=1; i<numColumns+1; i++) {
String column_name = rsmd.getColumnName(i);
if(rsmd.getColumnType(i)==java.sql.Types.ARRAY){
obj.put(column_name, rs.getArray(column_name));
}
else if(rsmd.getColumnType(i)==java.sql.Types.BIGINT){
obj.put(column_name, rs.getInt(column_name));
}
else if(rsmd.getColumnType(i)==java.sql.Types.BOOLEAN){
obj.put(column_name, rs.getBoolean(column_name));
}
else if(rsmd.getColumnType(i)==java.sql.Types.BLOB){
obj.put(column_name, rs.getBlob(column_name));
}
else if(rsmd.getColumnType(i)==java.sql.Types.DOUBLE){
obj.put(column_name, rs.getDouble(column_name));
}
else if(rsmd.getColumnType(i)==java.sql.Types.FLOAT){
obj.put(column_name, rs.getFloat(column_name));
}
else if(rsmd.getColumnType(i)==java.sql.Types.INTEGER){
obj.put(column_name, rs.getInt(column_name));
}
else if(rsmd.getColumnType(i)==java.sql.Types.NVARCHAR){
obj.put(column_name, rs.getNString(column_name));
}
else if(rsmd.getColumnType(i)==java.sql.Types.VARCHAR){
if (freitextlabel.length()>0 && column_name.equalsIgnoreCase("freitext"))
obj.put(freitextlabel, rs.getString(column_name));
else
obj.put(column_name, rs.getString(column_name));
}
else if(rsmd.getColumnType(i)==java.sql.Types.TINYINT){
obj.put(column_name, rs.getInt(column_name));
}
else if(rsmd.getColumnType(i)==java.sql.Types.SMALLINT){
obj.put(column_name, rs.getInt(column_name));
}
else if(rsmd.getColumnType(i)==java.sql.Types.DATE){
obj.put(column_name.concat("_js"), rs.getDate(column_name));
}
else if(rsmd.getColumnType(i)==java.sql.Types.TIMESTAMP){
//obj.put(column_name.concat("_js"), rs.getTimestamp(column_name,tzUTC));
Timestamp ts = rs.getTimestamp(column_name,tzUTC);
// obj.put (column_name, ts !=null ? new Date(ts.getTime) : null);
obj.put(column_name.concat("_js"), ts != null ? new Date(ts.getTime()) : null);
}
else{
obj.put(column_name, rs.getObject(column_name));
}
}
json.put(obj);
}
return json;
}
}