利用jackson转成json字符串（ssh中）

 public String getJsonString(Object o){
     ObjectMapper om = new ObjectMapper();
    StringWriter sw = new StringWriter();
    try{
       JsonGenerator jg = new JsonFactory().createJsonGenerator(ws);
       om.writeValue(jg,o);
       jg.close();
    }catch(){}
    return ws.toString() ;
 }

 public void writeJson(Object o) {
   String json = getJsonString(o);
   try{
       ServletActionContext.getResponse().getWriter().write(json);
    }catch(){}
 }