使用@RequestBody将请求体映射到Action方法参数中

     @PostMapping("/user")
     public User create(@RequestBody User user){
         System.out.println(user.toString());
         user.setId(5l);
         return user;
     }

     @Test
     public void whenCreateSuccess() throws Exception {
         String content = "{\"username\":\"fanqi\",\"password\":\"admin\",\"enabled\":\"1\"}";
         mockMvc.perform(MockMvcRequestBuilders.post("/user")
                 .contentType(MediaType.APPLICATION_JSON_UTF8)
                 .content(content))
                 .andExpect(status().isOk())
                 .andExpect(jsonPath("$.id").exists());
     }