JavaNote 4.7 读取配置文件的多种方式

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#java读取配置文件 #properties的读取 #配置文件的读取

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本文详细介绍了在Java环境中加载配置文件的六种常见方法，包括使用InputStream、Properties类、Spring的PropertiesLoaderUtils、FileInputStream、URL以及Apache Commons Configuration等，每种方法均有具体代码示例。

一、code

package com.test;


import org.apache.commons.configuration2.Configuration;
import org.apache.commons.configuration2.builder.fluent.Configurations;
import org.apache.commons.configuration2.ex.ConfigurationException;
import org.springframework.core.io.support.PropertiesLoaderUtils;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Properties;
import java.util.PropertyResourceBundle;
import java.util.ResourceBundle;

public class Test {
    public static void main(String args[]){
        Test test = new Test();
        test.method1();
        test.method2();
        test.method3();
        test.method4();
        test.method5();
        test.method6();

    }
    public void method1(){
        Properties properties = new Properties();
        /*
        * InputStream inputStream = Test.class.getResourceAsStream("/db.properties");
        * InputStream inputStream1 = Test.class.getClassLoader().getResourceAsStream("db.properties");
        * 上面两种方式可以达到一样的效果*/
        InputStream inputStream = ClassLoader.getSystemResourceAsStream("db.properties");
        try{
            /*new Exception().getStackTrace()[0].getMethodName() 输出本方法名,返回值String
            new Exception().getStackTrace()[0].getMethodName() 输出调用者的方法名，返回值String
            * */
            properties.load(inputStream);
            System.out.println("methodName:" + new Exception().getStackTrace()[0].getMethodName() + " ; " + "root:" + " " +  properties.getProperty("root"));
        }
        catch(IOException e){
            e.getMessage();
        }
    }
    public void method2(){
        Properties properties = new Properties();
        try {
            //通过Spring的PropertiesLoaderUtils.loadAllProperties载入配置文件
            properties = PropertiesLoaderUtils.loadAllProperties("db.properties");
            System.out.println("methodName:" + new Exception().getStackTrace()[0].getMethodName() + " ; "+ "password:" + " " + properties.getProperty("password"));
        }
        catch (IOException e){
            e.getMessage();
        }
    }
    public void method3(){
        Properties properties = new Properties();
        try {
            //通过IO输入流载入配置
            InputStream inStream = new FileInputStream(new File("src\\main\\resources\\db.properties"));
            properties.load(inStream);
            System.out.println("methodName:" + new Exception().getStackTrace()[0].getMethodName() + " ; "+ "root:" + " " + properties.getProperty("root"));
        }
        catch (IOException e){
            e.getMessage();
        }
    }
    public void method4(){
        Properties properties = new Properties();
        try {
            /*
            UrlResource urlResource = new UrlResource("file:target/classes/db.properties");
            InputStream inStream = urlResource.getInputStream();
            properties.load(inStream);
            System.out.println(properties.getProperty("password"));
*/
            //通过URL读取配置文件，和上面的UrlResource达到的效果一致
            URL url = new URL("file:src\\main\\resources\\db.properties");
            InputStream inStream1 = url.openStream();
            properties.load(inStream1);
            System.out.println("methodName:" + new Exception().getStackTrace()[0].getMethodName() + " ; "+ "root:" + " " + properties.getProperty("root"));

        }
        catch (MalformedURLException e){
            e.getMessage();
        }
        catch (IOException e){
            e.getMessage();
        }
    }
    public void method5(){
        //通过java.util.ResourceBundle类加载配置文件,ResourceBundle.getBundle("db")中没有使用配置文件后缀名
        ResourceBundle resource = ResourceBundle.getBundle("db");
        System.out.println("methodName:" + new Exception().getStackTrace()[0].getMethodName() + " ; "+ "root:" + " " +resource.getString("root") );
       //使用输入流方式载入配置文件
        InputStream inputStream1 = Test.class.getClassLoader().getResourceAsStream("db.properties");
        try {
            ResourceBundle resource1 = new PropertyResourceBundle(inputStream1);
            System.out.println("methodName:" + new Exception().getStackTrace()[0].getMethodName() + " ; "+ "password:" + " " +resource1.getString("password")+"2");
        }
        catch (IOException e){
            e.getMessage();
        }
    }
    public void method6(){
        Configurations configs = new Configurations();
        /*
        * 需要用到的commons-configuration2版本为2.0及以上，还需要用到commons-beanutils依赖包
        */
        try {
            Configuration config = configs.properties(new File("db.properties"));
            System.out.print("methodName:" + new Exception().getStackTrace()[0].getMethodName() + " ; "+ "root:" + " " +config.getString("root") );

        }
        catch (ConfigurationException e){
            e.getMessage();
        }
    }
}

二、输出截图

三、第六种方法的依赖包

<dependency>
  <groupId>org.apache.commons</groupId>
  <artifactId>commons-configuration2</artifactId>
  <version>2.3</version>
</dependency>
<dependency>
  <groupId>commons-beanutils</groupId>
  <artifactId>commons-beanutils</artifactId>
  <version>1.9.3</version>
</dependency>