一、在main目錄下建立 resources 並設為資源目錄

 二、直接上程式碼

引用

import org.springframework.util.ResourceUtils;

全部程式碼

package com.ConfigJson;

import java.io.*;
import java.util.Properties;

import org.springframework.util.ResourceUtils;

/**
 * Hello world!
 *
 */
public class App 
{
    public static void main( String[] args )
    {
        System.out.println( 
 
"Hello World!" );

        String json = readJsonFile("app_agentlist.json");
        System.out.println(json);
    }
  /**
     * 讀取  JSON 配置檔案
     */
    public static String readJsonFile(String fileName) {
        FileReader fileReader = null;
        Reader reader = null;
        try {
            File jsonFile 
 
= ResourceUtils.getFile("classpath:"+fileName);
            fileReader = new FileReader(jsonFile);
            reader = new InputStreamReader(new FileInputStream(jsonFile),"utf-8");
            int ch;
            StringBuffer sb = new StringBuffer();
            while ((ch = reader.read()) != -1) {
                sb.append((
 
char) ch);
            }
            fileReader.close();
            reader.close();
            String jsonStr = sb.toString();
            return jsonStr;
        } catch (IOException e) {
            e.printStackTrace();
            //logger.error("讀取檔案報錯", e);
            System.out.println("讀取檔案報錯!"+e);
        } finally {
            if(fileReader != null){
                try {
                    fileReader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if(reader != null){
                try {
                    reader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return null;
    }


}

三、app_agentlist.json

{
  "name": "resources",
  "version": "1.0.0",
  "dependencies": {

  }
}

四、pom.xml  （重點：，始終讀取不到 json 檔案，報錯，是因為 pom.xml 檔案裡面沒有配置 ）

<resources>
      <resource>
        <filtering>true</filtering>
        <directory>src/main/resources</directory>
        <includes>
          <include>**/*.properties</include>
          <include>**/*.xml</include>
          <include>**/*.json</include>
        </includes>
      </resource>
 </resources>

 五、執行結果

 感謝：

https://www.cnblogs.com/yuxiaole/p/9719954.html