PropertiesHelper——配置文件读取和写入工具类

import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import org.apache.commons.io.IOUtils;

import java.io.*;
import java.util.Properties;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.ReentrantLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

/**
 * 配置文件读取和写入工具类
 */
public class PropertiesHelper {
    private static final String DEFAULT_PROPERTIES_HEADER = "Configuration Info";
    private static final LoadingCache locks;
    private final String absolutePath;
    private final ReentrantReadWriteLock.ReadLock readLock;
    private final ReentrantReadWriteLock.WriteLock writeLock;


    static {
        locks = CacheBuilder.newBuilder().maximumSize(10).expireAfterWrite(10, TimeUnit.MINUTES)
                .build(new CacheLoader() {
                    public ReentrantReadWriteLock load(String key) {
                        return new ReentrantReadWriteLock();
                    }
                });
    }

    public PropertiesHelper(String filePath) {
        this.absolutePath = new File(filePath).getAbsolutePath();
        ReentrantReadWriteLock lock = locks.getUnchecked(absolutePath);
        readLock = lock.readLock();
        writeLock = lock.writeLock();
    }

    public String getProperty(String key, String defaultValue) {
        try {
            readLock.lock();
            Properties properties = getProperties();
            return properties.getProperty(key, defaultValue);
        } catch (Exception ) {
            e.printStackTrace();
            return defaultValue;
        } finally {
            readLock.unlock();
        }
    }

    public void setProperty(String key, String value) throws IOException {
        try {
            writeLock.lock();
            Properties prop = getProperties();
            prop.setProperty(key, value);
            saveProperties(prop);
        } finally {
            writeLock.unlock();
        }
    }

    public void removeProperty(String key) throws IOException {
        try {
            writeLock.lock();
            Properties prop = getProperties();
            prop.remove(key);
            saveProperties(prop);
        } finally {
            writeLock.unlock();
        }
    }

    public boolean containsKey(String key) throws Exception {
        try {
            readLock.lock();
            Properties prop = getProperties();
            return prop.containsKey(key);
        } finally {
            readLock.unlock();
        }
    }

    private void saveProperties(Properties prop) throws IOException {
        OutputStreamWriter writer = null;
        try {
            writer = new OutputStreamWriter(new FileOutputStream(absolutePath), "UTF-8");
            prop.store(writer, DEFAULT_PROPERTIES_HEADER);
            writer.flush();
        } finally {
            IOUtils.closeQuietly(writer);
        }
    }

    private Properties getProperties() throws IOException {
        InputStreamReader reader = null;
        try {
            Properties prop = new Properties();
            reader = new InputStreamReader(new FileInputStream(absolutePath), "UTF-8");
            prop.load(reader);
            return prop;
        } finally {
            IOUtils.closeQuietly(reader);
        }
    }
}