/**
 * Code contributed to the Learning Layers project
 * http://www.learning-layers.eu
 * Development is partly funded by the FP7 Programme of the European
 * Commission under Grant Agreement FP7-ICT-318209.
 * Copyright (c) 2014, Karlsruhe University of Applied Sciences.
 * For a list of contributors see the AUTHORS file at the top-level directory
 * of this distribution.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package de.hska.ld.core.config.security;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.security.core.Authentication;
import org.springframework.security.web.authentication.SimpleUrlAuthenticationSuccessHandler;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class AjaxAuthenticationSuccessHandler extends SimpleUrlAuthenticationSuccessHandler {

    private static final Logger LOGGER = LoggerFactory.getLogger(AjaxAuthenticationSuccessHandler.class);
    private static final ObjectMapper mapper = new ObjectMapper();

    @Override
    public void onAuthenticationSuccess(HttpServletRequest request, HttpServletResponse response,
                                        Authentication authentication) throws IOException, ServletException {

        String userJson = null;
        try {
            userJson = mapper.writeValueAsString(authentication.getPrincipal());
        } catch (JsonProcessingException e) {
            LOGGER.error(e.getMessage());
        }

        if (userJson != null) {
            response.getWriter().write(userJson);
            response.setStatus(HttpServletResponse.SC_OK);
        } else {
            response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
        }
    }
}

/**
 * Code contributed to the Learning Layers project
 * http://www.learning-layers.eu
 * Development is partly funded by the FP7 Programme of the European
 * Commission under Grant Agreement FP7-ICT-318209.
 * Copyright (c) 2014, Karlsruhe University of Applied Sciences.
 * For a list of contributors see the AUTHORS file at the top-level directory
 * of this distribution.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package de.hska.ld.core.config.security;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.security.core.Authentication;
import org.springframework.security.web.authentication.SimpleUrlAuthenticationSuccessHandler;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class AjaxAuthenticationSuccessHandler extends SimpleUrlAuthenticationSuccessHandler {

    private static final Logger LOGGER = LoggerFactory.getLogger(AjaxAuthenticationSuccessHandler.class);
    private static final ObjectMapper mapper = new ObjectMapper();

    @Override
    public void onAuthenticationSuccess(HttpServletRequest request, HttpServletResponse response,
                                        Authentication authentication) throws IOException, ServletException {

        String userJson = null;
        try {
            userJson = mapper.writeValueAsString(authentication.getPrincipal());
        } catch (JsonProcessingException e) {
            LOGGER.error(e.getMessage());
        }

        if (userJson != null) {
            response.setCharacterEncoding("UTF-8");
            response.getWriter().write(userJson);
            response.setStatus(HttpServletResponse.SC_OK);
        } else {
            response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
        }
    }
}

Set character encoding of of authentication success handler to UTF-8