用jackson输出标准的json字符串

 1 public class JacksonObjectMapperExample {
 2 
 3     public static String formatJson(String jsonStr) throws IOException {
 4         ObjectMapper objectMapper = new ObjectMapper();
 5         // 允许没有引号的字段名（非标准）
 6         objectMapper.configure(JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES, true);
 7         // 允许单引号（非标准）
 8         objectMapper.configure(JsonParser.Feature.ALLOW_SINGLE_QUOTES, true);
 9         Object json = objectMapper.readValue(jsonStr, Object.class);
10         //美化
11         //System.out.println(objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(json));
12         //objectMapper.configure(SerializationFeature.INDENT_OUTPUT, true);
13         //不美化
14         objectMapper.configure(SerializationFeature.INDENT_OUTPUT, false);
15 
16         return objectMapper.writeValueAsString(json);
17     }
18 
19     public static void main(String[] args) throws IOException {
20         String test = "{age:29,messages:[\"msg 1\",\"msg 2\",\"msg 3\"],\"name\":\"mkyong\"}";
21         System.out.println(formatJson(test));
22     }
23 }