ajax访问后台，得到一个对象，我怎么以json格式返回到前台。

Question

ajax访问servlet，查询得到一个message对象，我怎么把这个对象以json的格式返回给前台，并显示在给定的div中。

Answer 1

[code="java"]public class JsonServlet extends HttpServlet {

private org.codehaus.jackson.map.ObjectMapper objectMapper = new org.codehaus.jackson.map.ObjectMapper();

@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
        throws ServletException, IOException {

    resp.setContentType("application/json");

    try {
        User user = new User();
        user.setId("1");
        user.setName("user");
        objectMapper.writeValue(resp.getOutputStream(), user);
    } catch (Exception e) {
        // TODO: handle exception
    }

}

private static class User {

    private String id;

    private String name;

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

}

}[/code]
前台用jquery
[code="js"] $.post("", {}, function(user) {
alert(user.id, +" " + user.name);
}, "json");[/code]