提示
有时候会需要读取配置文件(.properties),无论是项目内还是项目外,于是从网上收集了一个工具类,进行了一些优化.
请注意:代码基于Jdk 9 编译.
代码
package xyz.suancaiyu.util;
import java.io.*;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
/**
* Properties 工具类
*
* @Author: puruidong
* @Version: 2018/3/15 17:29
*/
public class PropertiesUtil {
private static final String APPLICATIONFILEPATH = "F:\\conf\\application.properties";
private PropertiesUtil() {
}
private static PropertiesUtil propertiesUtil = null;
public static PropertiesUtil getInstance() {
if (propertiesUtil == null) {
propertiesUtil = new PropertiesUtil();
}
return propertiesUtil;
}
/**
* 根据文件名获取Properties对象
* <p>
* <p>
* 读取项目内部配置文件:
* <p>
* <p>
* in = PropertiesUtil.class.getClassLoader().getResourceAsStream(Constats.APPLICATIONFILEPATH);
*
* @return
*/
public Properties read() {
try(InputStream in = new FileInputStream(new File(APPLICATIONFILEPATH))) {
Properties prop = new Properties();
if (in == null) {
return null;
}
prop.load(in);
return prop;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/**
* 根据文件名和键名获取值
*
* @param key
* @return
*/
public String readKeyValue(String key) {
Properties prop = read();
if (prop != null) {
return prop.getProperty(key);
}
return null;
}
/**
* 根据键名获取值
*
* @param prop
* @param key
* @return
*/
public String readKeyValue(Properties prop, String key) {
if (prop != null) {
return prop.getProperty(key);
}
return null;
}
/**
* 写入
*
* @param fileName
* @param key
* @param value
*/
public void writeValueByKey(String fileName, String key, String value) {
Map<String, String> properties = new HashMap<>();
properties.put(key, value);
writeValues(properties);
}
/**
* 写入
*
* @param properties
*/
public void writeValues(Map<String, String> properties) {
try(InputStream in =new FileInputStream(new File(APPLICATIONFILEPATH));
OutputStream out = new FileOutputStream(APPLICATIONFILEPATH);) {
/*
如果是项目内的配置文件,需要使用下面这一行代码.
in = PropertiesUtil.class.getClassLoader().getResourceAsStream(APPLICATIONFILEPATH);
*/
if (in == null) {
throw new RuntimeException("读取的文件（" + APPLICATIONFILEPATH + "）不存在，请确认！");
}
Properties prop = new Properties();
prop.load(in);
// 项目内部配置文件才用这个.
// String path = PropertiesUtil.class.getResource( APPLICATIONFILEPATH).getPath();
if (properties != null) {
Set<String> set = properties.keySet();
for (String string : set) {
prop.setProperty(string, properties.get(string));
}
}
prop.store(out, "update properties");
} catch (Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
System.out.println(PropertiesUtil.getInstance().readKeyValue("libpath"));
Map<String, String> maps = new HashMap<>(2);
maps.put("add", "true");
PropertiesUtil.getInstance().writeValues(maps);
}
}
