rancher中，javaweb中的配置文件怎么通过configmap替换？

2021-03-08 19:59发布

站内问答 / Java
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3条回答
studentaaa
2021-03-19 07:39

方式一：采用ServletContext读取

获取配置文件的realpath，然后通过文件流读取出来或者通过方法getReasurceAsStream()。

因为是用ServletContext读取文件路径，所以配置文件可以放入在WEB-INF的classes目录中，也可以在应用层级及WEB-INF的目录中。文件存放位置具体在eclipse工程中的表现是：可以放在src下面，也可放在WEB-INF及Web-Root下面等。因为是读取出路径后，用文件流进行读取的，所以可以读取任意的配置文件包括xml和properties。缺点：不能在servlet外面应用读取配置信息。

1.首先创建一个动态的javaweb项目，项目目录如下：

2.创建一个servlet（FileReader.java）

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package com.xia.fileReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.text.MessageFormat;
import java.util.Properties;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class FileReader extends HttpServlet {
 private static final long serialVersionUID = 1L;
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 /**
 * response.setContentType("text/html;charset=UTF-8");目的是控制浏览器用UTF-8进行解码；
 * 这样就不会出现中文乱码了
 */
 response.setHeader("content-type","text/html;charset=UTF-8");
 readSrcDirPropCfgFile(response);//读取src目录下的db1.properties配置文件
 response.getWriter().println("
");
 readWebRootDirPropCfgFile(response);//读取WebRoot目录下的db2.properties配置文件
 response.getWriter().println("
");
 readSrcSourcePackPropCfgFile(response);//读取src目录下的config目录中的db3.properties配置文件
 response.getWriter().println("
");
 readWEBINFPropCfgFile(response);//读取WEB-INF目录下的JDBC目录中的db4.properties配置文件
 }
 public void readSrcDirPropCfgFile(HttpServletResponse response) throws IOException {
 String path = "/WEB-INF/classes/db1.properties";
 InputStream in = this.getServletContext().getResourceAsStream(path);
 Properties props = new Properties();
 props.load(in);
 String driver = props.getProperty("jdbc.driver");
 String url = props.getProperty("jdbc.url");
 String username = props.getProperty("jdbc.username");
 String password = props.getProperty("jdbc.password");
 response.getWriter().println("读取src目录下的db1.properties配置文件");
 response.getWriter().println(MessageFormat.format( "driver={0},url={1},username={2},password={3}",
 driver,url, username, password));
 }
 public void readWebRootDirPropCfgFile(HttpServletResponse response) throws IOException{
 String path = "/db2.properties";
 InputStream in = this.getServletContext().getResourceAsStream(path);
 Properties props = new Properties();
 props.load(in);
 String driver = props.getProperty("jdbc.driver");
 String url = props.getProperty("jdbc.url");
 String username = props.getProperty("jdbc.username");
 String password = props.getProperty("jdbc.password");
 response.getWriter().println("读取WebRoot目录下的db2.properties配置文件");
 response.getWriter().println(MessageFormat.format( "driver={0},url={1},username={2},password={3}",
 driver,url, username, password));
 }
 public void readSrcSourcePackPropCfgFile(HttpServletResponse response) throws IOException {
 String path = "/WEB-INF/classes/config/db3.properties";
 String realPath = this.getServletContext().getRealPath(path);
 InputStreamReader reader = new InputStreamReader(new FileInputStream(realPath),"UTF-8");
 Properties props = new Properties();
 props.load(reader);
 String driver = props.getProperty("jdbc.driver");
 String url = props.getProperty("jdbc.url");
 String username = props.getProperty("jdbc.username");
 String password = props.getProperty("jdbc.password");
 response.getWriter().println("读取src目录下的config目录中的db3.properties配置文件");
 response.getWriter().println(MessageFormat.format( "driver={0},url={1},username={2},password={3}",
 driver,url, username, password));
 }
 public void readWEBINFPropCfgFile(HttpServletResponse response) throws IOException {
 String path = "/WEB-INF/JDBC/db4.properties";
 String realPath = this.getServletContext().getRealPath(path);
 System.out.println("realPath："+realPath);
 System.out.println("contextPath："+this.getServletContext().getContextPath());
 InputStreamReader reader = new InputStreamReader(new FileInputStream(realPath),"UTF-8");
 Properties props = new Properties();
 props.load(reader);
 String driver = props.getProperty("jdbc.driver");
 String url = props.getProperty("jdbc.url");
 String username = props.getProperty("jdbc.username");
 String password = props.getProperty("jdbc.password");
 response.getWriter().println("读取WEB-INF目录下的JDBC目录中的db4.properties配置文件");
 response.getWriter().println(MessageFormat.format( "driver={0},url={1},username={2},password={3}",
 driver,url, username, password));
 }
 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 }
}


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