看Java怎样使用静态块读取属性文件代码

private static String driver =null

private static String url = null

private static String user = null

private static String password = null

private static BasicDataSource ds

static{

//读取程序外的.properties 文件

//需要.properties文件的包路径

Properties props = new Properties()

try {

String path ="db.properties"

props.load(

DBUtils.class.getResourceAsStream(path)

)

//properties对象.getProperty("字符串")

driver=props.getProperty("driver")

url=props.getProperty("url")

user=props.getProperty("user")

password=props.getProperty("password")

ds = new BasicDataSource()

ds.setDriverClassName(driver)

ds.setUrl(url)

ds.setUsername(user)

ds.setPassword(password)

Class.forName(driver)

} catch (Exception e) {

e.printStackTrace()

}

}

这是一个JDBC读取配置文件连接数据库的示例代码，供参考！

Map<String, String>map = new HashMap<String, String>()

map.put("key1", "value1")

map.put("key2", "value2")

map.put("key3", "value3")

Set<String>keySet = map.keySet()

int i = map.size()-1

Map<Integer, String>mapKey = new HashMap<Integer, String>()

Map<Integer, String>mapValue = new HashMap<Integer, String>()

for(java.util.Map.Entry<String, String>entry : map.entrySet()) {

//将原来MAP的VALUE放入新的MAP的VALUE里面

mapKey.put(i, entry.getValue())

//将原来MAP的KEY放入新的MAP的VALUE 里面

mapValue.put(i, entry.getKey())

i--

}

//打印KEY值

System.out.println(mapKey.get(2))

//打印VALUE值

System.out.println(mapValue.get(0))

}

---