Properties文件工具类的使用--获取所有的键值、删除键、更新键等操作
有时候我们希望处理properties文件，properties文件是键值对的文件形式，我们可以借助Properties类操作。
工具类如下:(代码中日志采用了slf4j日志)
package cn.xm.exam.utils; 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.util.Map.Entry;
import java.util.Properties; import org.slf4j.Logger;
import org.slf4j.LoggerFactory; /**
* 操作properties文件的工具类(此工具类的file都是src目录下的properties文件，编译之后在build目录下)
*
* @author QiaoLiQiang
* @time 2018年11月3日下午12:05:32
*/
public class PropertiesFileUtils {
private static final Logger log = LoggerFactory.getLogger(PropertiesFileUtils.class); /**
* 构造函数私有化
*/
private PropertiesFileUtils() { } /**
* 保存或更新properties文件中的key
*
* @param fileName
* @param key
* @param value
*/
public static void saveOrUpdateProperty(String fileName, String key, String value) {
Properties properties = new Properties();
InputStream inputStream;
OutputStream outputStream;
try {
String path = ResourcesUtil.class.getClassLoader().getResource(fileName).getPath();
log.debug("path -> {}", path);
inputStream = new FileInputStream(new File(path));
properties.load(inputStream);
properties.setProperty(key, value); // 保存到文件中(如果有的话会自动更新，没有会创建)
outputStream = new FileOutputStream(new File(path));
properties.store(outputStream, ""); outputStream.close();
inputStream.close();
} catch (FileNotFoundException e) {
log.error("saveOrUpdateProperty error", e);
} catch (IOException e) {
log.error("saveOrUpdateProperty error", e);
}
} /**
* 获取Properties
*
* @param fileName
* @param key
* @return
*/
public static String getPropertyValue(String fileName, String key) {
Properties properties = new Properties();
InputStream inputStream;
String value = "";
try {
String path = PropertiesFileUtils.class.getClassLoader().getResource(fileName).getPath();
log.info("path -> {}", path);
inputStream = new FileInputStream(new File(path));
properties.load(inputStream); value = properties.getProperty(key);
// 保存到文件中(如果有的话会自动更新，没有会创建)
inputStream.close();
} catch (FileNotFoundException e) {
log.error("saveOrUpdateProperty error", e);
} catch (IOException e) {
log.error("saveOrUpdateProperty error", e);
}
return value;
} /**
* 获取Properties
*
* @param fileName
* @return
*/
public static Properties getProperties(String fileName) {
Properties properties = new Properties();
InputStream inputStream;
try {
String path = PropertiesFileUtils.class.getClassLoader().getResource(fileName).getPath();
log.info("path -> {}", path);
inputStream = new FileInputStream(new File(path));
properties.load(inputStream); inputStream.close();
} catch (FileNotFoundException e) {
log.error("saveOrUpdateProperty error", e);
} catch (IOException e) {
log.error("saveOrUpdateProperty error", e);
}
return properties;
} /**
* 获取Properties
*
* @param fileName
* @return
*/
public static Properties removeProperty(String fileName, String key) {
Properties properties = new Properties();
InputStream inputStream;
OutputStream outputStream;
try {
String path = PropertiesFileUtils.class.getClassLoader().getResource(fileName).getPath();
log.info("path -> {}", path);
inputStream = new FileInputStream(new File(path));
properties.load(inputStream);
log.info("properties -> {}", properties);
if (properties != null && properties.containsKey(key)) {
log.info("remove key:{}", key);
properties.remove(key);
} // 保存到文件中(将properties保存到文件)
outputStream = new FileOutputStream(new File(path));
properties.store(outputStream, ""); outputStream.close();
inputStream.close();
} catch (FileNotFoundException e) {
log.error("saveOrUpdateProperty error", e);
} catch (IOException e) {
log.error("saveOrUpdateProperty error", e);
}
return properties;
} public static void main(String[] args) {
// 保存三个 最后一个相当于更新
PropertiesFileUtils.saveOrUpdateProperty("settings.properties", "a", "aaa");
PropertiesFileUtils.saveOrUpdateProperty("settings.properties", "b", "bbb");
PropertiesFileUtils.saveOrUpdateProperty("settings.properties", "c", "ccc");
PropertiesFileUtils.saveOrUpdateProperty("settings.properties", "a", "AAA"); // 获取所有的properties
Properties properties = PropertiesFileUtils.getProperties("settings.properties");
System.out.println(properties); // 删除a
PropertiesFileUtils.removeProperty("settings.properties", "a"); // 获取所有的properties
Properties properties1 = PropertiesFileUtils.getProperties("settings.properties");
System.out.println(properties1);
} }
结果:
{b=bbb, a=AAA, c=ccc}
{b=bbb, c=ccc}
解释:
Properties是继承了HashTable的一个普通类，所以我们可以简单的认为操作Properties就是在操作HashTable。
public
class Properties extends Hashtable<Object,Object> { private static final long serialVersionUID = 4112578634029874840L; protected Properties defaults;
。。。
}
由于HasTable键不可以重复，所以我们在saveOrUpdateProperty中直接setProperty的时候如果没有key会创建key，如果key存在会覆盖原来的值。
properties.load(inputStream);是将properties文件中的key=value的数据加载到properties中;
properties.store(outputStream, "");是将properties保存到一个文件中。
补充:上面代码还可以进一步将properties文件的位置封装全路径:
package cn.xm.exam.utils; 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.util.Properties; import org.slf4j.Logger;
import org.slf4j.LoggerFactory; /**
*
* @author QiaoLiQiang
* @time 2018年11月3日下午12:05:32
*/
public class PropertiesFileUtils {
private static final Logger log = LoggerFactory.getLogger(PropertiesFileUtils.class); /**
* 构造函数私有化
*/
private PropertiesFileUtils() { } /**
* 保存或更新properties文件中的key
*
* @param fileName
* @param key
* @param value
*/
public static void saveOrUpdateProperty(String fileName, String key, String value) {
Properties properties = new Properties();
InputStream inputStream;
OutputStream outputStream;
try {
String path = ResourcesUtil.class.getClassLoader().getResource(fileName).getPath();
log.debug("path -> {}", path);
inputStream = new FileInputStream(new File(path));
properties.load(inputStream);
properties.setProperty(key, value); // 保存到文件中(如果有的话会自动更新，没有会创建)
outputStream = new FileOutputStream(new File(path));
properties.store(outputStream, ""); outputStream.close();
inputStream.close();
} catch (FileNotFoundException e) {
log.error("saveOrUpdateProperty error", e);
} catch (IOException e) {
log.error("saveOrUpdateProperty error", e);
}
} /**
* 获取Properties
*
* @param fileName
* @param key
* @return
*/
public static String getPropertyValue(String fileName, String key) {
Properties properties = new Properties();
InputStream inputStream;
String value = "";
try {
String path = PropertiesFileUtils.class.getClassLoader().getResource(fileName).getPath();
log.info("path -> {}", path);
inputStream = new FileInputStream(new File(path));
properties.load(inputStream); value = properties.getProperty(key);
// 保存到文件中(如果有的话会自动更新，没有会创建)
inputStream.close();
} catch (FileNotFoundException e) {
log.error("saveOrUpdateProperty error", e);
} catch (IOException e) {
log.error("saveOrUpdateProperty error", e);
}
return value;
} /**
* 获取Properties
*
* @param fileName
* @return
*/
public static Properties getProperties(String fileName) {
Properties properties = new Properties();
InputStream inputStream;
try {
String path = PropertiesFileUtils.class.getClassLoader().getResource(fileName).getPath();
log.info("path -> {}", path);
inputStream = new FileInputStream(new File(path));
properties.load(inputStream); inputStream.close();
} catch (FileNotFoundException e) {
log.error("saveOrUpdateProperty error", e);
} catch (IOException e) {
log.error("saveOrUpdateProperty error", e);
}
return properties;
} /**
* 获取Properties
*
* @param fileName
* @return
*/
public static Properties removeProperty(String fileName, String key) {
Properties properties = new Properties();
InputStream inputStream;
OutputStream outputStream;
try {
String path = PropertiesFileUtils.class.getClassLoader().getResource(fileName).getPath();
log.info("path -> {}", path);
inputStream = new FileInputStream(new File(path));
properties.load(inputStream);
log.info("properties -> {}", properties);
if (properties != null && properties.containsKey(key)) {
log.info("remove key:{}", key);
properties.remove(key);
} // 保存到文件中(将properties保存到文件)
outputStream = new FileOutputStream(new File(path));
properties.store(outputStream, ""); outputStream.close();
inputStream.close();
} catch (FileNotFoundException e) {
log.error("saveOrUpdateProperty error", e);
} catch (IOException e) {
log.error("saveOrUpdateProperty error", e);
}
return properties;
} /**
* 保存或更新properties文件中的key
*
* @param path
* 文件全路径
* @param key
* @param value
*/
public static void saveOrUpdatePropertyByFilePath(String path, String key, String value) {
Properties properties = new Properties();
InputStream inputStream;
OutputStream outputStream;
try {
log.debug("path -> {}", path);
inputStream = new FileInputStream(new File(path));
properties.load(inputStream);
properties.setProperty(key, value); // 保存到文件中(如果有的话会自动更新，没有会创建)
outputStream = new FileOutputStream(new File(path));
properties.store(outputStream, ""); outputStream.close();
inputStream.close();
} catch (FileNotFoundException e) {
log.error("saveOrUpdateProperty error", e);
} catch (IOException e) {
log.error("saveOrUpdateProperty error", e);
}
} /**
* 获取Properties
*
* @param path
* 文件全路径
* @param key
* @return
*/
public static String getPropertyValueByFilePath(String path, String key) {
Properties properties = new Properties();
InputStream inputStream;
String value = "";
try {
log.info("path -> {}", path);
inputStream = new FileInputStream(new File(path));
properties.load(inputStream); value = properties.getProperty(key);
// 保存到文件中(如果有的话会自动更新，没有会创建)
inputStream.close();
} catch (FileNotFoundException e) {
log.error("saveOrUpdateProperty error", e);
} catch (IOException e) {
log.error("saveOrUpdateProperty error", e);
}
return value;
} /**
* 获取Properties
*
* @param path
* 文件全路径
* @return
*/
public static Properties getPropertiesByFilePath(String path) {
Properties properties = new Properties();
InputStream inputStream;
try {
log.info("path -> {}", path);
inputStream = new FileInputStream(new File(path));
properties.load(inputStream); inputStream.close();
} catch (FileNotFoundException e) {
log.error("saveOrUpdateProperty error", e);
} catch (IOException e) {
log.error("saveOrUpdateProperty error", e);
}
return properties;
} /**
* 获取Properties
*
* @param path
* 文件全路径
* @param key
* key值
* @return
*/
public static Properties removePropertyByFilePath(String path, String key) {
Properties properties = new Properties();
InputStream inputStream;
OutputStream outputStream;
try {
log.info("path -> {}", path);
inputStream = new FileInputStream(new File(path));
properties.load(inputStream);
log.info("properties -> {}", properties);
if (properties != null && properties.containsKey(key)) {
log.info("remove key:{}", key);
properties.remove(key);
} // 保存到文件中(将properties保存到文件)
outputStream = new FileOutputStream(new File(path));
properties.store(outputStream, ""); outputStream.close();
inputStream.close();
} catch (FileNotFoundException e) {
log.error("saveOrUpdateProperty error", e);
} catch (IOException e) {
log.error("saveOrUpdateProperty error", e);
}
return properties;
}
}
补充：如果是spring项目读取jar包中的配置可以用 ClassPathResource 进行读取:
/**
* 获取文件中对应的key的名称
*
* @param fileName
* @param key
* @return
*/
public static String getPropertyValue(String fileName, String key) {
Properties properties = new Properties();
InputStream inputStream = null;
String value = ""; try {
ClassPathResource resource = new ClassPathResource(fileName);
inputStream = resource.getInputStream();
properties.load(inputStream);
value = properties.getProperty(key);
} catch (Exception e) {
log.error("saveOrUpdateProperty error", e);
} finally {
IOUtils.closeQuietly(inputStream);
} return value;
}
补充：由于springboot打成jar包之后里面的文件不能实时修改，所以在当前程序的主目录下创建一settings.properties文件进行操作
package cn.qs.utils.system; import java.io.File;
import java.io.IOException;
import java.util.Date; import javax.servlet.http.HttpServletRequest; import org.apache.commons.io.FileUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.SystemUtils;
import org.apache.commons.lang3.time.DateFormatUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes; import cn.qs.bean.user.User;
import cn.qs.utils.UUIDUtils;
import cn.qs.utils.file.PropertiesFileUtils; public class MySystemUtils { private static final Logger LOGGER = LoggerFactory.getLogger(MySystemUtils.class); static {
checkSettingPropertyFiles();
} private MySystemUtils() {
} /**
* 检查settings.properties文件是否存在，不存在就创建
*/
public static void checkSettingPropertyFiles() {
File userDir = SystemUtils.getUserDir();
File propertiesFile = new File(userDir, "settings.properties");
if (!propertiesFile.exists()) {
try {
propertiesFile.createNewFile();
LOGGER.info("create settings.properties success, path: {}", propertiesFile.getAbsolutePath());
} catch (IOException e) {
LOGGER.error("create settings.properties failed", e);
}
}
} public static final String settings_file_path = SystemUtils.getUserDir().getAbsolutePath() + "/settings.properties"; public static String getProductName() {
return getProperty("productName", "管理网");
} public static String getProperty(String key) {
return getProperty(key, "");
} public static String getProperty(String key, String defaultValue) {
return StringUtils.defaultIfBlank(PropertiesFileUtils.getPropertyValueByFilePath(settings_file_path, key),
defaultValue);
} public static void setProperty(String key, Object value) {
PropertiesFileUtils.saveOrUpdatePropertyByFilePath(settings_file_path, key, String.valueOf(value));
} }
SystemUtils.getUserDir()方法获取的是项目所在的路径，如果是springboot打的jar包是jar包所在的目录。
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