spring boot读取json文件并实现接口查询

0.源码下载

https://download.csdn.net/download/IndexMan/84238085

1.说明

最近需要在spring boot项目启动时读取json文件并保存到List<模型>中，然后需要在controller中去访问使用。为了还原这个使用场景我做了个例子。

2.准备json文件

将user.json文件复制到spring boot项目的resource目录下。文件内容如下：

[
  {
    "id":1,
    "name": "小李",
    "gender": "男",
    "age": 18
  },
  {
    "id":2,
    "name": "小王",
    "gender": "女",
    "age": 18
  }
]

3.编写User模型

@Data
public class User {
    private Integer id;
    private String name;
    private String gender;
    private Integer age;
}

4.编写UserDao

@Component
public class UserDao {
    private static List<User> userList = new ArrayList<>();

    @Value("classpath:user.json")
    private Resource userResource;

    @PostConstruct
    public List<User> getUser(){
        try {
            String json = IOUtils.toString(userResource.getInputStream(), Charset.forName("UTF-8"));
            userList = JSONObject.parseArray(json, User.class);
        }
        catch (Exception e) {
            System.out.println(e.getMessage());
        }

        return userList;

    }

}

5.编写UserController

@RestController
public class UserController {
    @Autowired
    UserDao userDao;

    /**
     *  根据ID查询用户
     * @param id
     * @return
     */
    @GetMapping("/user/{id}")
    public Result<User> getUserById(@PathVariable Integer id){
        List<User> list = userDao.getUser();
        User user = null;
        for (User u:
                list) {
            if (u.getId().equals(id)){
                user = u;
                break;
            }
        }

        return ResultUtil.ok(user);
    }

    /**
     *  查询用户列表
     * @return
     */
    @GetMapping("/users")
    public Result<List<User>> getUserById(){
        return ResultUtil.ok(userDao.getUser());
    }
}

6.测试

浏览器访问：

6.1 查询用户列表

http://localhost:8080/users

6.2 根据ID查询用户

http://localhost:8080/user/1