Json工具 将对象转换为json格式字符串

@ResponseBody注解告知SpringMVC框架，方法返回的字符串不是跳转是直接在http响应体中返回。将对象转为json格式再转为字符串返回。

  
      com.fasterxml.jackson.core
      jackson-core
      2.9.0
    

    
      com.fasterxml.jackson.core
      jackson-databind
      2.9.0
    

    
      com.fasterxml.jackson.core
      jackson-annotations
      2.9.0
    

@Controller
@RequestMapping("/user")
public class UserController {
    @RequestMapping("/quick8")
    @ResponseBody
    public String save8() throws Exception {
        User user  = new User();
        user.setUsername("ll");
        user.setAge(30);
//        使用json转换工具将对象装换为json格式字符串
        ObjectMapper objectMapper = new ObjectMapper();
        String json =objectMapper.writeValueAsString(user);
        return json;
    }
 }