小程序锦集

读取本地文件

方式一：

    String encoding = "UTF-8";
    File file = new File("D:\\KJ.txt");
    if (file.isFile() && file.exists()) { //判断文件是否存在
        //考虑到编码格式
        BufferedReader br= new BufferedReader(new InputStreamReader(new FileInputStream(file), encoding));
        String line;
        String lineTxt = "";
        while ((line= bufferedReader.readLine()) != null) {
               lineTxt+= line;      
         }   
         parseJson(res); //解析字符串   
         br.close();
    } else {
        return "找不到指定的文件";
    }

方式二：

读取配置文件路径+利用commons-io工具读取文件

		<dependency>
			<groupId>commons-iogroupId>
			<artifactId>commons-ioartifactId>
			<version>2.5version>
		dependency>
		<dependency>
			<groupId>com.alibabagroupId>
			<artifactId>fastjsonartifactId>
			<version>1.2.6version>
		dependency>

@Test
	public void testJson(){
		Map<String, List<String>> map = new HashMap<String, List<String>>();
		InputStream in = null;                                             
		try {
			in = getClass().getClassLoader().getResourceAsStream("chip_model.json");
			String content = IOUtils.toString(in, "utf-8");
			map = JSON.parseObject(content, Map.class);
		} catch (Exception e) {
			
		}
	}

spring加载配置文件

// 会从类路径下查找配置文件(src/)
ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");

// 会从项目的根下查找配置文件(和src同级)
ApplicationContext ac = new FileSystemXmlApplicationContext("applicationContext.xml");

// 会从当前文件系统的D盘根目录下查找配置文件
ApplicationContext ac = new FileSystemXmlApplicationContext("d:/applicationContext.xml");

String—>Double,String—>Long Doolean—>boolean

String ua="iPhone8,2";
String uaNum=ua.toLowerCase().substring(6, ua.length());
String replace = uaNum.replace(",", "."); 
double replaceNum = Double.parseDouble(replace);//8.2

String os="12.1.1";
String [] str = os.split("\\.");
Long osNumber = Long.parseLong(str[0]);//12

boolean boolean = Boolean.booleanValue();

事务控制

链接：https://blog.csdn.net/roberts939299/article/details/77587425