Java读取Properties文件的六种方法

java教程 2年前 0 362

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());

ResourceBundle类是java自带的类，类路径：java.util.ResourceBundle，用来读取项目中后缀为properties的配置文件。

下面简单举例说明一下用法：

1. 数据准备

1）配置文件名称：application.properties（可将文件存放在工程的resource目录下，或者lib目录下）

2）配置文件内容：

dataBaseIp=127.0.0.1

user.name=root

user.password=123456

2. ResourceBundle类实现读取application.properties中key对应的value的步骤：

1）获取配置文件的名称，使用getBundle()方法

ResourceBundle resourceBundle = ResourceBundle.getBundle(“application”);//不需要写后缀名

2）获取资源文件中的信息：使用getString()方法

String dataBaseIp = resourceBundle.getString(“dataBaseIp”);//获取资源application中的dataBaseIp字段的值——127.0.0.1

String userName = resourceBundle.getString(“user.name”);//获取资源application中的user.name字段的值——root

3. 在工程中调用步骤2中读取到的值即可，不赘述。

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);

完整的示例，可以参考附件文件

JProperties.java文件

import java.util.*;
import java.io.InputStream;
import java.io.IOException;
import java.io.BufferedInputStream;
import java.io.FileInputStream;
 
 
public class JProperties {
 
public final static int BY_PROPERTIES = 1;
public final static int BY_RESOURCEBUNDLE = 2;
public final static int BY_PROPERTYRESOURCEBUNDLE = 3;
public final static int BY_CLASS = 4;
public final static int BY_CLASSLOADER = 5;
public final static int BY_SYSTEM_CLASSLOADER = 6;
 
public final static Properties loadProperties(final String name, final int type) throws IOException {
Properties p = new Properties();
InputStream in = null;
if (type == BY_PROPERTIES) {
in = new BufferedInputStream(new FileInputStream(name));
assert (in != null);
p.load(in);
} else if (type == BY_RESOURCEBUNDLE) {
ResourceBundle rb = ResourceBundle.getBundle(name, Locale.getDefault());
assert (rb != null);
p = new ResourceBundleAdapter(rb);
} else if (type == BY_PROPERTYRESOURCEBUNDLE) {
in = new BufferedInputStream(new FileInputStream(name));
assert (in != null);
ResourceBundle rb = new PropertyResourceBundle(in);
p = new ResourceBundleAdapter(rb);
} else if (type == BY_CLASS) {
assert (JProperties.class.equals(new JProperties().getClass()));
in = JProperties.class.getResourceAsStream(name);
assert (in != null);
p.load(in);
// return new JProperties().getClass().getResourceAsStream(name);
} else if (type == BY_CLASSLOADER) {
assert (JProperties.class.getClassLoader().equals(new JProperties().getClass().getClassLoader()));
in = JProperties.class.getClassLoader().getResourceAsStream(name);
assert (in != null);
p.load(in);
// return new JProperties().getClass().getClassLoader().getResourceAsStream(name);
} else if (type == BY_SYSTEM_CLASSLOADER) {
in = ClassLoader.getSystemResourceAsStream(name);
assert (in != null);
p.load(in);
}
 
if (in != null) {
in.close();
}
return p;
 
}

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