Rulon147

java 从零开始，学习笔记之基础入门（二十八）

数据库连接配置

配置方式一：

1. 在tomcat中输入地址http://localhost:8080/admin进入管理控制台，找到service节点中的host节点，在此节点中查找需要使用jndi服务的工程，并对其配置jndi服务。

2. 在工程中只需要使用服务即可，无需进行其他配置

Action中新建一个显示文件列表信息的servlet,ShowFileAction.

Showfile.jsp是此应用的视图，

ShowFileAction中需要调用FileOpenDAO来获得具体的数据

配置方式二：

context.xml

xml version="1.0" encoding="UTF-8"?>

<Resource name="sqlconn"

auth="Container"

type="javax.sql.DataSource"

driverClassName="com.microsoft.sqlserver.jdbc.SQLServerDriver"

url="jdbc:sqlserver://192.168.12.35:1433;databasename=j1201"

username="sa"

password="123"

maxAction="20"

maxIdle="10"

maxWait="10000"

Context>

Xml配置文件中部分关于jndi的配置

<resource-ref>

<description>jndidescription>

<res-ref-name>sqlconnres-ref-name>

<res-type>javax.sql.DataSourceres-type>

<res-auth>Containerres-auth>

resource-ref>

DataSourceFactory.java

package com.ibm.factory;

import javax.naming.Context;

import javax.naming.InitialContext;

import javax.sql.DataSource;

public class DataSourceFactory {

private static DataSource ds = null;

public static DataSource getDataSource(){

try{

Context context = new InitialContext();

//第一步：找到Java服务器中的系统环境变量

Context jceContext=(Context)context.lookup("java:comp/env");

//第二步“从系统环境变量中搜寻JNDI

ds=(DataSource)jceContext.lookup("sqlconn");

if(ds!=null){

System.out.println("从web服务器上找到数据源了");

}

}catch (Exception e){

e.printStackTrace();

}

return ds;

}

FileOpenDAO.java

package com.ibm.dao;

import java.sql.Connection;

import java.sql.ResultSet;

import java.sql.Statement;

import java.util.ArrayList;

import java.util.List;

import javax.sql.DataSource;

import com.ibm.dto.UFile;

import com.ibm.factory.DataSourceFactory;

/**

* 文件表操作

* @author 123

public class FileOpenDAO {

public List getFileList(){

DataSource ds=null;

Connection conn=null;

Statement stmt=null;

ResultSet rs=null;

List list=null;

try {

//获得数据源

ds=DataSourceFactory.getDataSource();

conn=ds.getConnection();

stmt=conn.createStatement();

rs=stmt.executeQuery("select * from filetb");

list=new ArrayList();

//循环读取数据并封装到list中

while(rs.next()){

UFile file=new UFile();

file.setFileId(rs.getInt("fileid"));

file.setFiName(rs.getString("finame"));

list.add(file);

}

} catch (Exception e) {

e.printStackTrace();

}finally{

try{

if(conn!=null){

conn.close();

}

}catch(Exception e){

e.printStackTrace();

}

return list;

}

// public static void main(String[] args) {

// FileOpenDAO ds= new FileOpenDAO();

// List list=ds.getFileList();

// for(UFile file:list){

// System.out.println(file.getFiName());

// System.out.println(list.get(0).getFileId());

// for (int i = 0; i < list.size(); i++) {

// System.out.println(list.get(i).getFileId()+list.get(i).getFiName());

// }

}

UFile.java

package com.ibm.dto;

/**

* 用户文件类

* @author 123

public class UFile {

private int fileId;

private String fiName;

public int getFileId() {

return fileId;

}

public void setFileId(int fileId) {

this.fileId = fileId;

}

public String getFiName() {

return fiName;

}

public void setFiName(String fiName) {

this.fiName = fiName;

}

ShowFileAction.java

package com.ibm.action;

import java.io.IOException;

import java.io.PrintWriter;

import java.util.List;

import javax.servlet.RequestDispatcher;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import com.ibm.dao.FileOpenDAO;

import com.ibm.dto.UFile;

public class ShowFileAction extends HttpServlet {

/**

* Constructor of the object.

public ShowFileAction() {

super();

}

/**

* Destruction of the servlet.

public void destroy() {

super.destroy(); // Just puts "destroy" string in log

// Put your code here

}

/**

* The doGet method of the servlet.

* This method is called when a form has its tag value method equals to get.

* @param request the request send by the client to the server

* @param response the response send by the server to the client

* @throws ServletException if an error occurred

* @throws IOException if an error occurred

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

FileOpenDAO fod = new FileOpenDAO();

List list=fod.getFileList();

//将文件列表信息存放在request对象中

request.setAttribute("filelist", list);

RequestDispatcher rd = request.getRequestDispatcher("showfile.jsp");

//服务器内部转发将文件列表信息传递到showfile.jsp页面

rd.forward(request, response);

}

/**

* The doPost method of the servlet.

* This method is called when a form has its tag value method equals to post.

* @param request the request send by the client to the server

* @param response the response send by the server to the client

* @throws ServletException if an error occurred

* @throws IOException if an error occurred

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("text/html");

PrintWriter out = response.getWriter();

out

.println("");

out.println("");

out.println(" A Servlet");

out.println(" ");

out.print(" This is ");

out.print(this.getClass());

out.println(", using the POST method");

out.println(" ");

out.println("");

out.flush();

out.close();

}

/**

* Initialization of the servlet.

* @throws ServletException if an error occurs

public void init() throws ServletException {

// Put your code here

}

showfile.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<%@page import="com.ibm.dto.UFile"%>

List list=(ArrayList)request.getAttribute("filelist");

DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

<head>

<title>My JSP 'showfile.jsp' starting pagetitle>

head>

<body>

<%for(UFile file:list){ %>

<%=file.getFiName() %>

<%} %>

body>

html>

上传附件功能代码

upload.html

<html >

<head>

$(function(){

var ei = $("#large");//获取Div

ei.hide();

$("#img1, img").mousemove(function(e){//img1是显示上传图片的缩略图

//鼠标经过的时候给div加上图片

ei.css({top:e.pageY,left:e.pageX}).html(' + this.src + '" />').show();

}).mouseout( function(){

ei.hide();//否则就隐藏

})

$("#f1").change(function(){ //上传控件上传的预览

// $("#img1").attr("src","file:///"+$("#f1").val());

$("#showimg").html(' + $("#f1").val() + '" />');

})

});

script>

#large{position:absolute;display:none;z-index:999;}

style>

head>

<body>

上传预览图片:<br>

<input type="text" name="uname" id="uname"/>姓名

<br>

form>

body>

html>

UploadAcion.java

package com.ibm.action;

import java.io.File;

import java.io.IOException;

import java.io.PrintWriter;

import java.util.List;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.apache.commons.fileupload.FileItem;

import org.apache.commons.fileupload.FileUploadException;

import org.apache.commons.fileupload.disk.DiskFileItemFactory;

import org.apache.commons.fileupload.servlet.ServletFileUpload;

public class UploadAction extends HttpServlet {

public UploadAction() {

super();

}

public void destroy() {

super.destroy(); // Just puts "destroy" string in log

// Put your code here

}

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("text/html");

PrintWriter out = response.getWriter();

out

.println("");

out.println("");

out.println(" A Servlet");

out.println(" ");

out.print(" This is ");

out.print(this.getClass());

out.println(", using the GET method");

out.println(" ");

out.println("");

out.flush();

out.close();

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

ServletFileUpload upload=new ServletFileUpload(new DiskFileItemFactory());

try {

//获得上传表单中所有传过来的组件

List list=upload.parseRequest(request);

//组建个数是

System.out.println("组件个数"+list.size());

for(FileItem fileItem:list){

//针对file组件的操作

if(!fileItem.isFormField()){

System.out.println("文件组件中的文本值名:"+fileItem.getName());

// System.out.println("组件值是:"+fileItem.getString());

System.out.println("组件名"+fileItem.getFieldName());

String imgupFile=this.getServletContext().getRealPath("myfile");

System.out.println("文件上传路径："+imgupFile);

//获得上传的文件名

String fileName=fileItem.getName();

fileName=fileName.substring(fileName.lastIndexOf("\\")+1);

//完整的文件存放地址

String path=imgupFile+File.separator+fileName;

System.out.println(path);

//利用fileTtem中的write方法将本地文件写入到服务器上

fileItem.write(new File(path));

} else{

//非file组件的操作

// System.out.println("组件名:"+fileItem.getFieldName());

// System.out.println("组件值是:"+fileItem.getString());

}

} catch (FileUploadException e) {

e.printStackTrace();

} catch (Exception e) {

e.printStackTrace();

}

public void init() throws ServletException {

// Put your code here

System.out.println("123");

}

总配置文件

xml version="1.0" encoding="UTF-8"?>

<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

<context-param>

<param-name>dbconfigparam-name>

<param-value>/WEB-INF/db.propertiesparam-value>

context-param>