Properties文件及与之相关的System.getProperties操作(转)

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如何使用Java读写系统属性？

读：

简述properties文件的结构和基本用法
结构：扩展名为properties的文件，内容为key、value的映射，例如"a=2"

示例用到的properties文件：

test.properties

a=testA
b:testB

package properties;import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.Enumeration;
import java.util.Properties;public class PropertiesManipulate { public static void main(String[] args) throws IOException {
readProperties();
readSystemProperties();
} private static void readSystemProperties() {
Properties props = System.getProperties();
Enumeration<?> prop_names = props.propertyNames();
while (prop_names.hasMoreElements()) {
String prop_name = (String) prop_names.nextElement();
String property = props.getProperty(prop_name);
System.out.println("Property \"" + prop_name + "\" is \"" + property
+ "\"");
}
} private static void readProperties() throws FileNotFoundException,
IOException {
String name = "test.properties";
InputStream in = new BufferedInputStream(new FileInputStream(name));
Properties p = new Properties();
p.load(in);
System.out.println("a==>" + p.getProperty("a"));
}}