$.ajax({
        	type: "POST",
            contentType: "application/json",
			url: 'save',
			data: StrToJSON(),
            success: function(data, textStatus, jqXHR) {
				if (data == "1") {
					alert("ОК");
				} else {
					alert(data);
				}

			}
        });

function StrToJSON() {
	return JSON.stringify({
	"id": $('#block1_id').val(),
	"addr": $('#block1_addr').val(),
	});

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        PrintWriter out = response.getWriter();

        String datasourceProperties = "/datasourceProperties";

        Props.init(this.getClass().getResource(datasourceProperties).getFile());
        ConnectionFactory.setConfigurtionProperties(Props.getAllProperties());

        String jsonString = new String();
        try {
            String line = "";
            BufferedReader reader = request.getReader();
            while ((line = reader.readLine()) != null)
                jsonString += line;
        } catch (Exception e) {
            e.printStackTrace();
        }

        A1 a1 = new Gson().fromJson(jsonString, A1.class);

        out.write(a1.getAddr());

    }

byte[] b = jsonString.getBytes("ISO-8859-1");
A1 a1  = new Gson().fromJson(new String(b,"UTF-8"), A1.class);

import org.json.simple.JSONObject;
import org.json.simple.parser.ParseException;
import org.json.simple.parser.JSONParser;

...

        response.setCharacterEncoding("UTF-8");
        request.setCharacterEncoding("UTF-8");
        response.setContentType("text/html; charset=utf-8");

A1 a1 = new A1();
try{
        Object obj = new JSONParser().parse(jsonString);
        JSONObject obj2 = (JSONObject)obj;
         a1.setId((String)obj2.get("id"));
         a1.setAddr((String)obj2.get("addr"));
}catch(ParseException pe){
    System.out.println("position: " + pe.getPosition());
    System.out.println(pe);
}