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

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;
        try {
            String path = PropertiesFileUtils.class.getClassLoader().getResource(fileName).getPath();
            log.info("path -> {}", path);
            inputStream = new FileInputStream(new File(path));
            properties.load(inputStream);

            for (Entry<Object, Object> entry : properties.entrySet()) {
                log.info("key -> {}， value -> {}", entry.getKey(), entry.getValue());
            }

            // 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 "";
    }

    /**
     * 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);
    }

}

public
class Properties extends Hashtable<Object,Object> {

     private static final long serialVersionUID = 4112578634029874840L;

    protected Properties defaults;
。。。
}