Java读取Properties文件的六种方法

 

Java读取Properties文件的六种方法

使用J2SE API读取Properties文件的六种方法

1。使用java.util.Properties类的load()方法
示例： InputStream in = lnew BufferedInputStream(new FileInputStream(name));
Properties p = new Properties();
p.load(in);

2。使用java.util.ResourceBundle类的getBundle()方法
示例： ResourceBundle rb = ResourceBundle.getBundle(name, Locale.getDefault());

3。使用java.util.PropertyResourceBundle类的构造函数
示例： InputStream in = new BufferedInputStream(new FileInputStream(name));
ResourceBundle rb = new PropertyResourceBundle(in);

4。使用class变量的getResourceAsStream()方法
示例： InputStream in = JProperties.class.getResourceAsStream(name);
Properties p = new Properties();
p.load(in);

5。使用class.getClassLoader()所得到的java.lang.ClassLoader的getResourceAsStream()方法
示例： InputStream in = JProperties.class.getClassLoader().getResourceAsStream(name);
Properties p = new Properties();
p.load(in);

6。使用java.lang.ClassLoader类的getSystemResourceAsStream()静态方法
示例： InputStream in = ClassLoader.getSystemResourceAsStream(name);
Properties p = new Properties();
p.load(in);

补充

Servlet中可以使用javax.servlet.ServletContext的getResourceAsStream()方法
示例：InputStream in = context.getResourceAsStream(path);
Properties p = new Properties();
p.load(in);

 

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以下是具体例子：

 

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.net.URL;

import java.util.Properties;

public class Test {

//path需要文件的绝对路径

public static String readProperties(String fileName, String parameterName) {

String filePath=Test.class.getResource("/")+"";

//替换所获得路径的/bin为/src

//conf/表示配置文件所在的包名，根据不同的包进行修改

String fPath=filePath.replaceAll("/bin","/src")+"conf/"+fileName;

//去掉path前面的file:/

String path = fPath.replaceAll("file:/","");

System.out.println(path);

File file = new File(path);

String value = "";

Properties prop = new Properties();

try {

InputStream fis = new FileInputStream(file);

prop.load(fis);

value = prop.getProperty(parameterName);

} catch (Exception e) {

e.printStackTrace();

}

return value;

}

public static Properties readProperties2(String fileName, String parameterName) {

String filePath=Test.class.getResource("/")+"";

String fPath=filePath.replaceAll("/bin","/src")+"conf/"+fileName;

String path = fPath.replaceAll("file:/","");

System.out.println(path);

File file = new File(path);

Properties prop = new Properties();

try {

InputStream fis = new FileInputStream(file);

prop.load(fis);

// value = prop.getProperty(parameterName);

} catch (Exception e) {

e.printStackTrace();

}

return prop;

}

public static void writeProperties(Properties prop,String fileName){

String filePath=Test.class.getResource("/")+"";

String fPath=filePath.replaceAll("/bin","/src")+"conf/"+fileName;

String path = fPath.replaceAll("file:/","");

System.out.println(path);

File file = new File(path);

try {

OutputStream fos = new FileOutputStream(file);

// 调用 Hashtable 的方法 put。

prop.setProperty("jdbc.url", "新的字符串");

// 以适合使用 load 方法加载到 Properties 表中的格式，

// 将此 Properties 表中的属性列表（键和元素对）写入输出流

prop.store(fos, "Update '" + "x" + "' value");

} catch (FileNotFoundException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

}

public static void main(String args[]){

String fileName="1.properties";

Properties properties = readProperties2(fileName,"jdbc.url");

writeProperties(properties,fileName);

System.out.println(readProperties(fileName,"jdbc.url"));

}

}