参考

Java中读取properties配置文件的八种方式总结_java读取配置文件的方式-CSDN博客

代码

需要读取的配置文件

application.properties

db1.username = zhangsan
db1.password = 123

db2.username = lisi
db2.password = 456

文件读取

package demo1;

import java.io.FileInputStream;
import java.io.InputStream;
import java.util.Properties;

public class Encrypt {

	public static void main(String[] args) throws Exception {
		InputStream inputStream = new FileInputStream("application.properties");
        Properties properties = new Properties();
        properties.load(inputStream);
        String property = properties.getProperty("db1.username");
        System.out.println("property = " + property);
	}

}