本文讲解如何用java实现把数据库的数据写入到txt中 并实现类似下载软件的样子在网页中弹出下载.

package datatest;import java.io.BufferedOutputStream;import java.io.IOException;import java.io.UnsupportedEncodingException;import java.net.URLEncoder;import java.sql.ResultSet;import java.sql.SQLException;import javax.servlet.ServletException;import javax.servlet.ServletOutputStream;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import bean.ConnDB;public class export extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //设置编码 response.setCharacterEncoding("UTF-8"); //连接数据库 ConnDB conn = new ConnDB(); ServletOutputStream outputstream = null; BufferedOutputStream buffoutputstream = null; String txt_name = "导出的txt文件名.txt";//导出的txt文件名 try { response.reset();// 清空输出流 response.setContentType("text/plain;charset=utf-8"); //设置txt文件名称编码，防止中文乱码 response.setHeader("Content-disposition", "attachment; filename="+URLEncoder.encode(txt_name, "UTF-8")); StringBuffer write = new StringBuffer(); outputstream=response.getOutputStream(); buffoutputstream = new BufferedOutputStream(outputstream); //根据id查询数据库 int id=Integer.parseInt(request.getParameter("id")); String sql = "select a.id,name,account,password "; sql+="from test_rank a "; sql+="left join test_join b on b.id=a.id where a.id="+id; ResultSet rs = conn.doQuery(sql); String content=""; try { while(rs.next()) { //把数据库中读取的数据写入 content=rs.getString("name")+"\r\n";//在txt中换行为\t\n write.append(content); content=rs.getString("account")+"\r\n"; write.append(content); break; } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } //write.append(content); //设置编码 防止中文乱码 String str = new String(write.toString().getBytes(),"gbk"); buffoutputstream.write(str.toString().getBytes("gbk")); buffoutputstream.flush(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } finally { if (outputstream != null) try { outputstream.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } if (buffoutputstream != null) try { buffoutputstream.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doGet(request, response); }}

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