java的下载代码 java程序下载

javaweb下载的代码怎么写

这个是用spSmartUpload实现的 使用的时候导入smartupload的jar包

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jsp页面

body

%

File f = new File("e:\\abc\\");

String[] fnames = f.list();

for(int i = 0; i fnames.length; i++){

%

a href="down?fname=%=fnames[i]%"%=fnames[i]%/abr

%}%

/body

servlet中

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

String fname = new String(request.getParameter("fname").getBytes(

"iso-8859-1"));

SmartUpload su = new SmartUpload();

su.initialize(getServletConfig(), request, response);// 初始化

try {

su.setContentDisposition(null);//出现下载提示

su.downloadFile("e:\\abc\\" + fname);

} catch (SmartUploadException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

java下载方面的代码

你的这段代码有两处让人疑惑。其一、File()这个构造函数，自已查下API

其二、FileOutputStream，FileOutputStream(String name)创建一个向具有指定名称的文件中写入数据的输出文件流。它只是创建了一个输出流，其中没有具体的值，那么这个值来自哪呢，其就来自于你的输入流。其中FileOutputStream()中只是创建了一个字节输出流，其只能接受字节流的输出，所以它还需要与DataOutputStream()的配合才能完成输出，具体用法你可以查API

求一个Java实现自动下载的源代码

您好，这样的：

/**

*

*/

package com.b510.base.bean.install;

import java.io.File;

import java.io.FileWriter;

import java.text.SimpleDateFormat;

import java.util.Date;

/**

* @author hongten(hongtenzone@foxmail.com)

* @date 2013-2-24

*/

@SuppressWarnings("unchecked")

public class BeanUtils {

//公共部分

private static final String RT_1 = "\r\n";

private static final String RT_2 = RT_1+RT_1;

private static final String BLANK_1 =" ";

private static final String BLANK_4 =" ";

private static final String BLANK_8 =BLANK_4 + BLANK_4;

//注释部分

private static final String ANNOTATION_AUTHOR_PARAMTER = "@author ";

private static final String ANNOTATION_AUTHOR_NAME = "hongten(hongtenzone@foxmail.com)";

private static final String ANNOTATION_AUTHOR = ANNOTATION_AUTHOR_PARAMTER + ANNOTATION_AUTHOR_NAME;

private static final String ANNOTATION_DATE = "@date ";

private static final String ANNOTATION = "/**"+RT_1+BLANK_1+"*"+BLANK_1+ANNOTATION_AUTHOR +RT_1+BLANK_1+"*"+BLANK_1+ANNOTATION_DATE +getDate()+RT_1+BLANK_1+"*/"+RT_1;

//文件 地址

//private static final String BEAN_PATH = "com/b510/base/bean";

private static final String DAO_PATH = "com/b510/base/dao";

private static final String DAO_IMPL_PATH = "com/b510/base/dao/impl";

private static final String SERVICE_PATH = "com/b510/base/service";

private static final String SERVICE_IMPL_PATH = "com/b510/base/service/impl";

//包名

private static final String BEAN_URL = "com.b510.base.bean";

private static final String DAO_URL = "com.b510.base.dao";

private static final String DAO_IMPL_URL = "com.b510.base.dao.impl";

private static final String SERVICE_URL = "com.b510.base.service";

private static final String SERVICE_IMPL_URL = "com.b510.base.service.impl";

//基本类名称

private static final String BASE_DAO_NAME = DAO_URL + ".BaseDao";

private static final String ABSTRACT_BASE_DAO_IMPL_NAME = DAO_IMPL_URL + ".AbstractBaseDaoImpl";

private static final String BASE_SERVICE_NAME = SERVICE_URL + ".BaseService";

private static final String ABSTRACT_BASE_SERVICE_IMPL_NAME = SERVICE_IMPL_URL + ".AbstractBaseServiceImpl";

/**

* 创建bean的Daobr

*

* @param c

* @throws Exception

*/

public void createBeanDao(Class c) throws Exception {

String cName = c.getName();

String fileName = System.getProperty("user.dir") + "/src/" + DAO_PATH

+ "/" + getLastChar(cName) + "Dao.java";

File f = new File(fileName);

FileWriter fw = new FileWriter(f);

fw.write("package "+DAO_URL+";"+RT_2+ANNOTATION+"public interface " +

getLastChar(cName) + "Dao extends "+BASE_DAO_NAME+" " + cName + " {"+RT_2+"}");

fw.flush();

fw.close();

showInfo(fileName);

}

/**

* 创建bean的Dao的实现类

* @param c

* @throws Exception

*/

public void createBeanDaoImpl(Class c) throws Exception{

String cName = c.getName();

String fileName = System.getProperty("user.dir") + "/src/" + DAO_IMPL_PATH

+ "/" + getLastChar(cName) + "DaoImpl.java";

File f = new File(fileName);

FileWriter fw = new FileWriter(f);

fw.write("package "+DAO_IMPL_URL+";"+RT_2+ANNOTATION+"public class " +

getLastChar(cName) + "DaoImpl extends "+ABSTRACT_BASE_DAO_IMPL_NAME+"" +

cName + " implements "+DAO_URL+"."+getLastChar(cName)+"Dao{"+RT_2+"}");

fw.flush();

fw.close();

showInfo(fileName);

}

/**

* 创建bean的service

* @param c

* @throws Exception

*/

public void createBeanService(Class c) throws Exception{

String cName = c.getName();

String fileName = System.getProperty("user.dir") + "/src/" + SERVICE_PATH

+ "/" + getLastChar(cName) + "Service.java";

File f = new File(fileName);

FileWriter fw = new FileWriter(f);

fw.write("package "+SERVICE_URL+";"+RT_2+ANNOTATION+"public interface " +

getLastChar(cName) + "Service extends "+BASE_SERVICE_NAME+""+ cName +"{"+RT_2+"}");

fw.flush();

fw.close();

showInfo(fileName);

}

/**

* 创建bean的service的实现类

* @param c

* @throws Exception

*/

public void createBeanServiceImpl(Class c) throws Exception{

String cName = c.getName();

String fileName = System.getProperty("user.dir") + "/src/" + SERVICE_IMPL_PATH

+ "/" +getLastChar(cName)+"ServiceImpl.java";

File f = new File(fileName);

FileWriter fw = new FileWriter(f);

fw.write("package "+SERVICE_IMPL_URL+";"+RT_2+ANNOTATION+"public class "

+ getLastChar(cName) + "ServiceImpl extends "+ABSTRACT_BASE_SERVICE_IMPL_NAME+""+ cName

+ " implements "+SERVICE_URL+"."+getLastChar(cName)+"Service{"+RT_2+BLANK_4

+"private "+DAO_URL+"."+getLastChar(cName)+"Dao "+getLowercaseChar(getLastChar(cName))

+"Dao;"+RT_2+BLANK_4+"public void set"+getLastChar(cName)+"Dao("+DAO_URL+"."+getLastChar(cName)+"Dao "

+getLowercaseChar(getLastChar(cName))+"Dao){"+RT_1+BLANK_8+"this."+getLowercaseChar(getLastChar(cName))+"Dao = "

+getLowercaseChar(getLastChar(cName))+"Dao;"+RT_1+BLANK_4+"}"+RT_2+BLANK_4+"@Override"+RT_1+BLANK_4

+"public "+DAO_URL+"."+"BaseDao"+BEAN_URL+"."+getLastChar(cName)+" getBaseDao(){"+RT_1+BLANK_8

+"return "+getLowercaseChar(getLastChar(cName))+"Dao;"+RT_1+BLANK_4+"}"+RT_2+"}");

fw.flush();

fw.close();

showInfo(fileName);

}

/**

* 获取路径的最后面字符串br

* 如：br

* codestr = "com.b510.base.bean.User"/codebr

* code return "User";code

* @param str

* @return

*/

public String getLastChar(String str) {

if ((str != null) (str.length() 0)) {

int dot = str.lastIndexOf('.');

if ((dot -1) (dot (str.length() - 1))) {

return str.substring(dot + 1);

}

}

return str;

}

/**

* 把第一个字母变为小写br

* 如：br

* codestr = "UserDao";/codebr

* codereturn "userDao";/code

* @param str

* @return

*/

public String getLowercaseChar(String str){

return str.substring(0,1).toLowerCase()+str.substring(1);

}

/**

* 显示信息

* @param info

*/

public void showInfo(String info){

System.out.println("创建文件："+ info+ "成功！");

}

/**

* 获取系统时间

* @return

*/

public static String getDate(){

SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");

return simpleDateFormat.format(new Date());

}

}