Java Web系统初始化时从数据库中加载数据到文本（ibatis，spring）

快来打我* 2022-08-06 00:17 162阅读 0赞

有一些特殊情况，需要在系统初始化时加载一些配置属性到本地文本中

web.xml

<listener>
    		<listener-class>
    			org.springframework.web.context.ContextLoaderListener
    		</listener-class>
    	</listener>
    	
    	
    	<listener>
        	        <listener-class>com.actions.common.listener.InitConfig</listener-class>  
      	</listener>

InitConfig.java

package com.actions.common.listener;
    
    import javax.servlet.ServletContextEvent;
    import javax.servlet.ServletContextListener;
    
    import org.springframework.web.context.WebApplicationContext;
    import org.springframework.web.context.support.WebApplicationContextUtils;
    
    import com.dao.impl.ConfigDaoImpl;
    import com.sun.org.apache.commons.logging.Log;
    import com.sun.org.apache.commons.logging.LogFactory;
    
    /**
     * 功能：初始化配置文件，从数据库中将配置文件中的数据写到本地
     * @author Adam
     *
     */
    public class InitConfig implements ServletContextListener{
    	private final Log log = LogFactory.getLog(getClass());
    	
    	public void contextDestroyed(ServletContextEvent sce) {
    		log.info("系统停止...");
    	}
    
    	public void contextInitialized(ServletContextEvent sce) {
    		log.info("System initialization Start...");
    		WebApplicationContext rwp = WebApplicationContextUtils.getRequiredWebApplicationContext(sce.getServletContext());
    		ConfigDaoImpl configDaoImpl= (ConfigDaoImpl)rwp.getBean("configDaoImpl");
    		configDaoImpl.initConfig();
    		log.info("System initialization End...");  
    	}
    
    }

spring.xml

ConfigDaoImpl.java

package com.dao.impl;
    
    import java.io.File;
    import java.util.List;
    import java.util.Properties;
    
    import org.springframework.transaction.annotation.Transactional;
    
    import com.pojos.MyConfig;
    import com.util.FileUtils;
    
    /**
     * 功能：从数据库中将配置文件信息写入本地。
     * @author Adam
     *
     */
    @Transactional
    public class ConfigDaoImpl extends BaseDaoImpl{
    	String profilepath = ConfigDaoImpl.class.getClassLoader().
    	getResource("").getPath() + "config.txt";
    	
    	Properties props = new Properties();
    	
    	/**
    	 * 功能：初始化配置文件
    	 */
    	public void initConfig(){
    		try {
    			profilepath = profilepath.replaceAll("%20", " ");
    			File outputFile = new File(profilepath);
    			
    			outputFile.createNewFile();
    			//把所有可用值都写入文本
    			List list = this.getAllKeyAndValue();
    			if(list != null && list.size()>0){
    				String content = "";
    				for(int i =0 ; i < list.size(); i++ ){
    					MyConfig con = (MyConfig) list.get(i);
    					if(content.equals("")){
    						content = con.getCon_key()+"="+con.getCon_value();
    					}else{
    						content = content + "\r" + con.getCon_key()+"="+con.getCon_value();
    					}
    				}
    				FileUtils.writeFileUTF8(content,profilepath);
    			}
    		} catch (Exception e) {
    			e.printStackTrace();
    		}
    	}
    	
    	public String getValueByKey(String con_key) throws Exception {
    		return (String) super.findByObj("MyConfig.getValueByKey", con_key);
    	}
    	
    	public List getAllKeyAndValue() throws Exception{
    		return super.findAll("MyConfig.getAllKeyAndValue");
    	}
    }

FileUtils.java

package com.util;
    
    import java.io.BufferedInputStream;
    import java.io.BufferedOutputStream;
    import java.io.BufferedReader;
    import java.io.BufferedWriter;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileOutputStream;
    import java.io.FileWriter;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.InputStreamReader;
    import java.io.OutputStream;
    import java.io.OutputStreamWriter;
    
    /**
     * 文件工具类
     * FileUtils
     * @version 1.0
     */
    public class FileUtils {
    	static String root_path = FileUtils.class.getClassLoader().
    	getResource("").getPath() + "config.txt";
    	
    	public static String getValueByKey(String con_key){
    		try {
    			root_path = root_path.replaceAll("%20", " ");
    			File file = new File(root_path);
    			FileInputStream fis = new FileInputStream(file);
    			BufferedReader br = new BufferedReader(new InputStreamReader(fis,
    					"UTF-8"));
    			String line = br.readLine();
    			while (line!= null) {
    				if(line.indexOf(con_key)>=0){
    					String [] arr = line.split("=");
    					if(arr[0].equals(con_key)){
    						return arr[1];
    					}
    				}else{
    					line = br.readLine();
    				}
    			}
    			br.close();
    			fis.close();
    		} catch (Exception e) {
    			e.printStackTrace();
    		}
    		return "";
    	}
    }

Constant.java

public interface Constant {
    	public static final String SYSTEM_ROOT = FileUtils.getValueByKey("SYSTEM_ROOT");
    }