spring注解读取json文件

开发时候在接口没有提供的时候，可以用json文件提前模拟接口数据或者自己开发些工具类的网站不想带数据库也可以用本地json数据

实现原理是利用自定义参数注解@Value获取到本地json文件，然后利用Scanner来读取json文件

1.service层

package com.syp.spring.service;

import java.io.File;
import java.util.Scanner;
import java.util.concurrent.TimeUnit;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.core.io.Resource;
import org.springframework.stereotype.Service;


@Service
public class TestService {
    @Value(value="classpath:resource/rest.json")
    private  Resource data;    
    
    public String getData(){
        try {
            File file = data.getFile();
            long t0 = System.nanoTime();
            String jsonData = this.jsonRead(file);
            long t1 = System.nanoTime();
            long millis = TimeUnit.NANOSECONDS.toMillis(t1-t0);
            System.out.println(millis +"ms");
            return jsonData;
        } catch (Exception e) {
            return null;
        }
    }
    /**
     *     读取文件类容为字符串
     * @param file
     * @return
     */
      private String jsonRead(File file){
            Scanner scanner = null;
            StringBuilder buffer = new StringBuilder();
            try {
                scanner = new Scanner(file, "utf-8");
                while (scanner.hasNextLine()) {
                    buffer.append(scanner.nextLine());
                }
            } catch (Exception e) {
                
            } finally {
                if (scanner != null) {
                    scanner.close();
                }
            }
            return buffer.toString();
        }

}

2.controller层

package com.syp.spring.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

import com.syp.spring.service.TestService;

@Controller
@RequestMapping(value="/syp/spring")
public class TestController {
    
    @Autowired 
    private TestService testService;
    
    @RequestMapping(method=RequestMethod.GET)
    @ResponseBody
    public String test(){
        return testService.getData();
    }
}