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Java读取Properties配置文件的6种方式汇总

作者:怡人蝶梦

这篇文章主要给大家介绍了关于Java读取Properties配置文件的6种方式,java中的properties文件是一种配置文件,主要用于表达配置信息,文中通过示例代码介绍的非常详细,需要的朋友可以参考下

Java读取Properties的方式

项目结构:经典的maven项目结构

配置文件1和2内容一致:

jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=mysql://localhost:3306/database?useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai
jdbc.username=root
jdbc.password=123456

1. this.getClass().getResourceAsStream()

//读取配置文件1
public void readProperties1() throws IOException {
    //不加/会从当前包进行寻找,加上/会从src开始找
    InputStream inputStream = this.getClass().getResourceAsStream("/jdbc.properties");
    Properties properties=new Properties();
    properties.load(inputStream);
    System.out.println("jdbc.driver="+properties.getProperty("jdbc.driver"));
    System.out.println("jdbc.url="+properties.getProperty("jdbc.url"));
    System.out.println("jdbc.username="+properties.getProperty("jdbc.username"));
    System.out.println("jdbc.password="+properties.getProperty("jdbc.password"));
}
//读取配置文件2        
 public void readProperties1() throws IOException {
        InputStream inputStream = this.getClass().getResourceAsStream("/config/jdbc2.properties");
        Properties properties=new Properties();
        properties.load(inputStream);
        System.out.println("jdbc.driver="+properties.getProperty("jdbc.driver"));
        System.out.println("jdbc.url="+properties.getProperty("jdbc.url"));
        System.out.println("jdbc.username="+properties.getProperty("jdbc.username"));
        System.out.println("jdbc.password="+properties.getProperty("jdbc.password"));
}

2.当前类的加载器进行读取this.getClass().getClassLoader().getResourceAsStream()

//读取配置文件1
public void readProperties2() throws IOException {
    //不加/,若加了会为null
    InputStream inputStream = this.getClass().getClassLoader().getResourceAsStream("jdbc.properties");
    Properties properties=new Properties();
    properties.load(inputStream);
    System.out.println("jdbc.driver="+properties.getProperty("jdbc.driver"));
    System.out.println("jdbc.url="+properties.getProperty("jdbc.url"));
    System.out.println("jdbc.username="+properties.getProperty("jdbc.username"));
    System.out.println("jdbc.password="+properties.getProperty("jdbc.password"));
}
//读取配置文件2
public void readProperties2() throws IOException {
        InputStream inputStream = this.getClass().getClassLoader().getResourceAsStream("config/jdbc2.properties");
        Properties properties=new Properties();
        properties.load(inputStream);
        System.out.println("jdbc.driver="+properties.getProperty("jdbc.driver"));
        System.out.println("jdbc.url="+properties.getProperty("jdbc.url"));
        System.out.println("jdbc.username="+properties.getProperty("jdbc.username"));
        System.out.println("jdbc.password="+properties.getProperty("jdbc.password"));
}

方法1和2区别: (classpath即为target/classes 这个目录)

Class.getResourceAsStream() 从当前类所在的位置开始查找配置文件位置。要找到jdbc.properties和jdbc2.properties必须加/从classpath下开始查找

Class.getClassLoader().getResourceAsStream() 默认就从classpath路径下开始查找,加上/会报空指针

十分有必要知道java中类的加载过程!!!

3. ClassLoader类的static方法 getSystemResourceAsStream()

public void readProperties3() throws IOException {
        //InputStream inputStream = ClassLoader.getSystemResourceAsStream("config/jdbc2.properties");
        InputStream inputStream = ClassLoader.getSystemResourceAsStream("jdbc.properties");
        Properties properties=new Properties();
        properties.load(inputStream);
        System.out.println("jdbc.driver="+properties.getProperty("jdbc.driver"));
        System.out.println("jdbc.url="+properties.getProperty("jdbc.url"));
        System.out.println("jdbc.username="+properties.getProperty("jdbc.username"));
        System.out.println("jdbc.password="+properties.getProperty("jdbc.password"));
    }

4. Spring中的 ClassPathResource读取

public void readProperties4() throws IOException {
        //ClassPathResource resource = new ClassPathResource("jdbc.properties");
        ClassPathResource resource = new ClassPathResource("config/jdbc2.properties");
        Properties properties= PropertiesLoaderUtils.loadProperties(resource);
        System.out.println("jdbc.driver="+properties.getProperty("jdbc.driver"));
        System.out.println("jdbc.url="+properties.getProperty("jdbc.url"));
        System.out.println("jdbc.username="+properties.getProperty("jdbc.username"));
        System.out.println("jdbc.password="+properties.getProperty("jdbc.password"));
}

5. PropertyResourceBundle读取InputStream流

public void readProperties5() throws IOException {
        //InputStream inputStream = ClassLoader.getSystemResourceAsStream("jdbc.properties");
    	InputStream inputStream = ClassLoader.getSystemResourceAsStream("config/jdbc2.properties");
        PropertyResourceBundle bundle = new PropertyResourceBundle(inputStream);
        System.out.println(bundle.getString("jdbc.driver"));
        System.out.println(bundle.getString("jdbc.url"));
        System.out.println(bundle.getString("jdbc.username"));
        System.out.println(bundle.getString("jdbc.password"));
    }

6.ResourceBundle.getBundle()

//不用输入后缀
public void readProperties6()  {
        //ResourceBundle bundle=ResourceBundle.getBundle("jdbc");
        ResourceBundle bundle=ResourceBundle.getBundle("config/jdbc2");
        System.out.println(bundle.getString("jdbc.driver"));
        System.out.println(bundle.getString("jdbc.url"));
        System.out.println(bundle.getString("jdbc.username"));
        System.out.println(bundle.getString("jdbc.password"));
    }

总结

到此这篇关于Java读取Properties配置文件的6种方式的文章就介绍到这了,更多相关Java读取Properties配置文件内容请搜索脚本之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持脚本之家!

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