java（包括springboot）讀取resources下文件方式

1、使用項目內路徑讀取，該路徑只在開發工具中顯示，類似：src/main/resources/resource.properties。只能在開發工具中使用，部署之後無法讀取。（不通用）

　　File file = new File("src/main/resources/resource.properties");

 

@Test
    public void testReadFile2() throws IOException {
        File file = new File("src/main/resources/resource.properties");
        FileInputStream fis = new FileInputStream(file);
        InputStreamReader isr = new InputStreamReader(fis);
        BufferedReader br = new BufferedReader(isr);
        String data = null;
        while((data = br.readLine()) != null) {
            System.out.println(data);
        }
        
        br.close();
        isr.close();
        fis.close();
    }

2、使用org.springframework.util.ResourceUtils，讀取。在linux環境中無法讀取。（不通用）

File file = ResourceUtils.getFile("classpath:resource.properties");
FileInputStream fis = new FileInputStream(file);

 

@Test
    public void testReadFile3() throws IOException {
        File file = ResourceUtils.getFile("classpath:resource.properties");
        FileInputStream fis = new FileInputStream(file);
        InputStreamReader isr = new InputStreamReader(fis);
        BufferedReader br = new BufferedReader(isr);
        String data = null;
        while((data = br.readLine()) != null) {
            System.out.println(data);
        }
        
        br.close();
        isr.close();
        fis.close();
    }

3、使用org.springframework.core.io.ClassPathResource，各種環境都能讀取。（通用）

Resource resource = new ClassPathResource("resource.properties");
InputStream is = resource.getInputStream();

package com.wjj.application.util;

import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;

import java.io.*;

/**
 * @author hank
 */
public class SpringUtils {
    private SpringUtils(){};
    public static String readResource(String path) throws IOException {
        Resource resource = new ClassPathResource(path);
        InputStream is = resource.getInputStream();
        InputStreamReader isr = new InputStreamReader(is);
        BufferedReader br = new BufferedReader(isr);
        String data = null;
        StringBuilder content = new StringBuilder();
        while((data = br.readLine()) != null) {
            content.append(data);
        }
        br.close();
        isr.close();
        is.close();
        return content.toString();
    }
}

4、結合spring註解，使用org.springframework.core.io.ResourceLoader;類的註解。（通用）

package com.tsinkai.ettp;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.test.context.junit4.SpringRunner;

@RunWith(SpringRunner.class)
@SpringBootTest
public class EttpCustomApplicationTests {

    @Autowired
    ResourceLoader resourceLoader;
    
    
    @Test
    public void testReaderFile() throws IOException {
        Resource resource = resourceLoader.getResource("classpath:resource.properties");
        InputStream is = resource.getInputStream();
        InputStreamReader isr = new InputStreamReader(is);
        BufferedReader br = new BufferedReader(isr);
        String data = null;
        while((data = br.readLine()) != null) {
            System.out.println(data);
        }
        
        br.close();
        isr.close();
        is.close();
    }

}