java 读取配置文件并应用 *.property
最近在学习Java框架应用，所以从配置文件，并读取配置文件开始学习。
此处以读取SystemGlobals.properties为例
SystemGlobals.properties 中的内容如下：
#cache
use_cache=1
cache.implement = com.cqa.platform.cache.MemCacheEngine
cache.mem.initConn = 5
cache.mem.maxConn = 250
cache.mem.maxIdle = 50
cache.mem.maintSleep = 30
cache.mem.socketTO = 3000
cache.mem.socketConnectTO = 0
cache.mem.nagle = false
cache.mem.servers = 192.168.0.11:11211,192.168.0.11:11210
#log
log.show_sql=true
use_cache=1
cache.implement = com.cqa.platform.cache.MemCacheEngine
cache.mem.initConn = 5
cache.mem.maxConn = 250
cache.mem.maxIdle = 50
cache.mem.maintSleep = 30
cache.mem.socketTO = 3000
cache.mem.socketConnectTO = 0
cache.mem.nagle = false
cache.mem.servers = 192.168.0.11:11211,192.168.0.11:11210
#log
log.show_sql=true
SystemGlobals.java中的内容如下：
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;
import java.util.Map.Entry;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.commons.lang.StringUtils;
/**
* @Description 系统变量加载类
* @ClassName SystemGlobals
*/
public class SystemGlobals {
/** The preferences. the value of it all is String*/
private static Properties preferences = new Properties();
/** The queries. */
private static Properties queries = new Properties();
private static Map<String, Object> objectProperties = new HashMap<String, Object>();
/**
* Gets the preference.
*
* @param key
* the key
* @return the preference
*/
public static String getPreference(String key) {
String s = preferences.getProperty(key);
if (s != null)
s = s.trim();
return s;
}
/**
* Gets the preference.
*
* @param key
* the key
* @param defaultValue
* the default value
* @return the preference
*/
public static String getPreference(String key, String defaultValue) {
String s = preferences.getProperty(key);
if (s == null)
return defaultValue;
else
return s;
}
/**
* Gets the preference.
*
* @param key
* the key
* @param params
* the params
* @return the preference
*/
public static String getPreference(String key, Object... params) {
String message = preferences.getProperty(key);
if (message != null)
message = message.trim();
if (params == null || params.length == 0)
return message;
String[] ss = new String[params.length];
Object o = null;
for (int i = 0; i < params.length; i++) {
o = params[i];
if (o == null) {
ss[i] = "";
} else {
ss[i] = o.toString();
}
}
return replacePlaceHolder(message, ss);
}
/**
* Sets the preference.
*
* @param key
* the key
* @param value
* the value
*/
public static void setPreference(String key, String value) {
if (value != null) {
value = value.trim();
preferences.setProperty(key, value);
} else {
preferences.remove(key);
}
}
/**
* Gets the int preference.
*
* @param key
* the key
* @param defaultValue
* the default value
* @return the int preference
*/
public static int getIntPreference(String key, int defaultValue) {
String s = getPreference(key);
if (StringUtils.isBlank(s))
return defaultValue;
else
return Integer.parseInt(s);
}
/**
* Sets the int preference.
*
* @param key
* the key
* @param value
* the value
*/
public static void setIntPreference(String key, int value) {
setPreference(key, String.valueOf(value));
}
/**
* Gets the long preference.
*
* @param key
* the key
* @param defaultValue
* the default value
* @return the long preference
*/
public static long getLongPreference(String key, long defaultValue) {
String s = getPreference(key);
if (StringUtils.isBlank(s))
return defaultValue;
else
return Long.parseLong(s);
}
/**
* Sets the long preference.
*
* @param key
* the key
* @param value
* the value
*/
public static void setLongPreference(String key, long value) {
setPreference(key, String.valueOf(value));
}
/**
* Gets the boolean preference.
*
* @param key
* the key
* @param defaultValue
* the default value
* @return the boolean preference
*/
public static boolean getBooleanPreference(String key, boolean defaultValue) {
String s = getPreference(key);
if (StringUtils.isBlank(s))
return defaultValue;
else
return Boolean.parseBoolean(s);
}
/**
* Sets the boolean preference.
*
* @param key
* the key
* @param value
* the value
*/
public static void setBooleanPreference(String key, boolean value) {
setPreference(key, String.valueOf(value));
}
/**
* Gets the sql.
*
* @param key
* the key
* @return the sql
*/
public static String getSql(String key) {
return queries.getProperty(key);
}
/**
* Load sql.
*
* @param file
* the file
*/
public static void loadSql(String file) {
try {
InputStream is = SystemGlobals.class.getClassLoader() .getResourceAsStream(file);
queries.load(is);
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* Load config.
*
* @param file
* the file
*/
public static void loadConfig(String file) {
try {
InputStream is = SystemGlobals.class.getClassLoader() .getResourceAsStream(file);
preferences.load(is);
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* Replace place holder.
*
* @param message
* the message
* @param params
* the params
* @return the string
*/
private static String replacePlaceHolder(String message, String[] params) {
if (StringUtils.isBlank(message))
return message;
if (params == null || params.length == 0)
return message;
Map<String, String> map = new HashMap<String, String>();
int index = -1;
Pattern p = Pattern.compile("\\{(\\d+)\\}");
Matcher m = p.matcher(message);
while (m.find()) {
if (m.groupCount() < 1)
continue;
index = Integer.parseInt(m.group(1));
if (index < 0 || index >= params.length)
continue;
map.put(m.group(0), params[index]);
}
if (map.isEmpty())
return message;
for (Entry<String, String> entry : map.entrySet()) {
message = message.replace(entry.getKey(), entry.getValue());
}
return message;
}
/**
* The main method.
*
* @param args
* the arguments
*/
public static void main(String[] args) {
String s = "thia is a {2} or a {1} {0} hahah";
String[] params = { "AA", "BB", "CC" };
Map<String, String> map = new HashMap<String, String>();
int index = -1;
Pattern p = Pattern.compile("\\{(\\d+)\\}");
Matcher m = p.matcher(s);
while (m.find()) {
if (m.groupCount() < 1)
continue;
index = Integer.parseInt(m.group(1));
if (index < 0 || index >= params.length)
continue;
map.put(m.group(0), params[index]);
}
for (Entry<String, String> entry : map.entrySet()) {
s = s.replace(entry.getKey(), entry.getValue());
}
System.out.println(s);
}
public static void setObjectValue(String field, Object value) {
objectProperties.put(field, value);
}
public static Object getObjectValue(String field) {
return objectProperties.get(field);
}
/** The Constant DB_JNDI. */
public static final String DB_JNDI = "db_jndi";
/** The Constant DB_USERNAME. */
public static final String DB_USERNAME = "db_userName";
/** The Constant DB_PASSWD. */
public static final String DB_PASSWD = "db_password";
/** The Constant DB_URL. */
public static final String DB_URL = "db_url";
/** The Constant SPRING_CONFIG. */
public static final String SPRING_CONFIG = "spring_config";
}
在web.xml中进行配置如下：
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<context-param>
<param-name>com.cqa.config.file</param-name>
<param-value>SystemGlobals.properties</param-value>
</context-param>
<listener>
<listener-class>com.company.listener.ConfigInitializer</listener-class>
</listener>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
ConfigInitializer.java 会在程序不完全启动时执行，其的内容为：
import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import org.apache.commons.lang.StringUtils;
import com.company.util.SystemGlobals;
public class ConfigInitializer implements ServletContextListener {
public void contextDestroyed(ServletContextEvent event) {
ServletContext context = event.getServletContext();
}
public void contextInitialized(ServletContextEvent event) {
ServletContext servletContext = event.getServletContext();
String configFile = servletContext.getInitParameter("com.cqa.config.file");
if (!StringUtils.isBlank(configFile)) {
configFile = configFile.trim();
SystemGlobals.loadConfig(configFile);
}
int useCache = SystemGlobals.getIntPreference("use_cache", 0);
System.out.println("useCache=="+useCache);
}
}
可以看到
SystemGlobals.getIntPreference("name","default")方法并有其他方法放在该java类里了。
以后在程序中可以任意使用。