java缓存代码实现，以及properties文件读取

最新推荐文章于 2024-05-16 15:37:55 发布

最新推荐文章于 2024-05-16 15:37:55 发布 · 91 阅读

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#Java #UI #Cache

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本文介绍了一个使用Java实现的单例模式缓存管理器，通过ConcurrentHashMap存储缓存项，并提供了增删查改的方法。同时，还展示了如何通过Properties类来读取配置文件。

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用map进行缓存

package edu.bupt626.asc.ui.cache;

import java.util.Collection;
import java.util.Date;
import java.util.concurrent.ConcurrentHashMap;
//单例模式

public class CacheManager {
	private static CacheManager cacheManager;
	// key: code
	private ConcurrentHashMap<String, CodeInfo> codeMap;

	public static CacheManager getInstance(){
		if(cacheManager == null){
			init();
		}
		return cacheManager;
	}

	private static synchronized void init(){
		if(cacheManager == null)
			cacheManager = new CacheManager();
	}

	private CacheManager(){
		codeMap = new ConcurrentHashMap<String, CodeInfo>();
	}

	public boolean addCode(String code, int state){
		CodeInfo info = codeMap.get(code);
		if(info == null){
			codeMap.put(code, new CodeInfo(code, state, new Date()));
			return true;
		}
		else if(info.getState() != state){
			info.setState(state);
			info.setTimestamp(new Date());
		}

		return false;
	}

	public CodeInfo getCode(String code){
		return codeMap.get(code);
	}

	public Collection<CodeInfo> getCodeInfos(){
		return codeMap.values();
	}

	public Collection<String> getCodes(){
		return codeMap.keySet();
	}

	public void removeCode(String code){
		codeMap.remove(code);
	}
}

被缓存实体类CodeInfo

package edu.bupt626.asc.ui.cache;

import java.util.Date;

public class CodeInfo {
	private String code;
	public String getCode() {
		return code;
	}

	public void setCode(String code) {
		this.code = code;
	}

	private int state;
	private Date timestamp;

	CodeInfo(String code, int state, Date timestamp){
		this.code = code;
		this.state = state;
		this.timestamp = timestamp;
	}

	public int getState() {
		return state;
	}

	public void setState(int state) {
		this.state = state;
	}

	public Date getTimestamp() {
		return timestamp;
	}

	public void setTimestamp(Date timestamp) {
		this.timestamp = timestamp;
	}
}

java读配置文件.properties的类
.properties文件：
key = value1
key2 = value2

package edu.bupt626.acs.ui.util;

import java.io.IOException;
import java.util.Properties;
//单例模式
public class AppContext {
	private static AppContext instance;
	private Properties properties;
	// the name of the configuration file
	public static final String CONFIG_FILE = "/server.properties";

	private static synchronized void init() {
		if (instance == null)
			instance = new AppContext();
	}

	public static AppContext getInstance() {
		if (instance == null)
			init();

		return instance;
	}

	private AppContext() {
		// Load the property file
		properties = new Properties();
		try {
			properties.load(AppContext.class.getResourceAsStream(CONFIG_FILE));

		} catch (IOException e) {
						e.printStackTrace();
		}
	}

	public Properties getProperties() {
		return properties;
	}
}

当需要读取配置文件中信息时，调用即可

	Properties props = AppContext.getInstance().getProperties();
		String obj = props.getProperty(配置文件中的key值);