此文用于java学习，在此小记。
在此之前有写过一些小的Java Demo，由于时间隔得比较长故而淡忘了，重新拾起。
环境的安装
开发环境：Win7(x64)+MyEclipse 2014+Mysql5.5.34+Navicat
MyEclipse 2014的安装和破解网上有很多资料，可自行查找，这里不再过多叙述。我这里安装的是myeclipse-pro-2014-GA-offline-installer-windows，破解文件用的是Myeclipse-2014-破解文件。顺便安装了一个webstrom，编辑jsp，xml，html非常方便。
Mysql的安装网上也有许多文档，最新版本的安装与之前的有一些差异，这个个人爱好。Mysql5.5.34，顺便安装了一个数据库管理工具Navicat。
数据库的建立
mysql数据库安装以后，在系统环境中添加相应的路径，具体查看相关的资料。运行cmd.exe，使用命令mysql -h localhost -u username -p password,显示mysql的版本后表示mysql的环境安装成功。
。
如图，点击连接测试，如果配置正常，则返回成功。
创建数据库test_db,创建表fruits
填充数据
建立WebProject工程
在MyEclipse下建立Web Project工程，默认有index.jsp和web.xml(WEB-INF下)两个文件，新建两个package，com.cn.add以及com.cn.query,在这两个package下分别新建Servlet，相应的配置会自动添加到web.xml中，
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0"> <servlet> <description>This is the description of my J2EE component</description> <display-name>This is the description of my J2EE component</display-name> <servlet-name>addServlet</servlet-name> <servlet-class>com.cn.add.addServlet</servlet-class> </servlet> <servlet> <description>This is the description of my J2EE component</description> <display-name>This is the display name of my J2EE component</display-name> <servlet-name>SearchEmployee</servlet-name> <servlet-class>com.cn.query.SearchEmployee</servlet-class> </servlet> <servlet> <description>This is the description of my J2EE component</description> <display-name>This is the display name of my J2EE component</display-name> <servlet-name>DeptList</servlet-name> <servlet-class>com.cn.query.DeptList</servlet-class> </servlet> <servlet-mapping> <servlet-name>addServlet</servlet-name> <url-pattern>/servlet/addServlet</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>SearchEmployee</servlet-name> <url-pattern>/servlet/SearchEmployee</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>DeptList</servlet-name> <url-pattern>/servlet/DeptList</url-pattern> </servlet-mapping> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> </web-app>
然后添加相应的实现功能，
数据库添加数据：addServlet.java
package com.cn.add; import java.io.IOException; import java.io.PrintWriter; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.SQLException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.sql.rowset.serial.SerialException; public class addServlet extends HttpServlet{ /** * Constructor of the object. */ public addServlet(){ super(); } /** * DEstruction of the servlet */ public void destory(){ super.destroy(); } /** * */ public void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException{ // try{ response.setContentType("text/html;charset=gb2312"); PrintWriter out = response.getWriter(); this.doPost(request, response); out.flush(); out.close(); // String f_id,f_name,tmp_id,tmp_price; // int s_id; // float f_price; // // f_id = request.getParameter("f_id"); // f_name = request.getParameter("f_name"); // // tmp_id = request.getParameter("s_id"); // tmp_price = request.getParameter("f_price"); // // s_id = Integer.parseInt(tmp_id); // f_price = Float.parseFloat(tmp_price); // } // catch(Exception ex){ // ex.printStackTrace(); // } } public void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException{ System.out.println("到了Servlet！！！"); response.setContentType("text/html;charset=gb2312"); request.setCharacterEncoding("gb2312"); PrintWriter out = response.getWriter(); String f_id = request.getParameter("f_id"); String str_id = request.getParameter("s_id"); String f_name = request.getParameter("f_name"); String str_price = request.getParameter("f_price"); int s_id = Integer.parseInt(str_id); float f_price = Float.parseFloat(str_price); Connection conn = null; PreparedStatement pstmt = null; try{ Class.forName("com.mysql.jdbc.Driver"); System.out.println("创建驱动成功!"); //连接数据库 conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test_db","root", "123456"); System.out.println("连接数据库成功！"); //插入数据的SQL语句 String sql = "INSERT INTO fruits(f_id,s_id,f_name,f_price) VALUES(?,?,?,?)"; pstmt = conn.prepareStatement(sql); //设置插入数据的顺序 pstmt.setString(1, f_id); pstmt.setInt(2,s_id); pstmt.setString(3, f_name); pstmt.setFloat(4, f_price); int result = pstmt.executeUpdate(); //判断执行结果 if(1 == result){ out.println("插入数据成功！"); }else{ out.println("插入数据库失败！请重新插入！"); } }catch(ClassNotFoundException e) { e.printStackTrace(); }catch(SQLException ex){ ex.printStackTrace(); } } public void init() throws ServletException{ } private String convertToChinese(String source) { String s = ""; try{ s = new String(source.getBytes("ISO8859_1")); } catch(java.io.UnsupportedEncodingException ex) { ex.printStackTrace(); } return s; } }
相对应的html文件：add.html
<!DOCTYPE html> <html> <head> <title>简单的水果表单</title> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="descripttion" content="this is my page"> <meta http-equiv="content-type" content="text/html; charset=GB2312"> </head> <body> <form action="http://localhost:8080/JavaServlet/servlet/addServlet" method="post"> <table border="0" cellpadding="3"> <tr> <td>水果简称代号:</td> <td><input type="text" name="f_id"></td> </tr> <tr> <td>水果编号:</td> <td><input type="text" name="s_id"></td> </tr> <tr> <td>水果名称:</td> <td><input type="text" name="f_name"></td> </tr> <tr> <td>水果价格:</td> <td><input type="text" name="f_price"></td> </tr> <tr> <td align="center" colspan="2"> <input type="submit" value="提交"> <input type="reset" value="重置"> </td> </tr> </table> </form> </body> </html>
查找SearchEmployee.java
package com.cn.query; import java.io.IOException; import java.io.PrintWriter; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class SearchEmployee extends HttpServlet { /** * Constructor of the object. */ public SearchEmployee() { super(); } /** * Destruction of the servlet. <br> */ public void destroy() { super.destroy(); // Just puts "destroy" string in log // Put your code here } /** * The doGet method of the servlet. <br> * * 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 { response.setContentType("text/html;charset=gb2312"); response.setCharacterEncoding("gb2312"); PrintWriter out = response.getWriter(); String f_name = request.getParameter("f_name"); Connection conn = null; PreparedStatement pstmt = null; ResultSet rs = null; try{ Class.forName("com.mysql.jdbc.Driver"); System.out.println("创建驱动成功！"); }catch(Exception e){ System.out.println("Class Not found!!!"); } try{ //连接数据库 conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test_db","root", "123456"); System.out.println("连接数据库成功！"); String sql = "SELECT * FROM fruits WHERE f_name = ?"; pstmt = conn.prepareStatement(sql); pstmt.setString(1, f_name); rs = pstmt.executeQuery(); }catch(SQLException ex){ ex.printStackTrace(); } try{ while(rs.next()){ out.println("水果简称代号:"+rs.getString(1)+" </br>"); out.println("水果编号:"+rs.getString(2)+" </br>"); out.println("水果名称:"+rs.getString(3)+" </br>"); out.println("水果价格:"+rs.getString(4)+" </br>"); } }catch(SQLException e){ e.printStackTrace(); } out.flush(); out.close(); } /** * The doPost method of the servlet. <br> * * 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;charset=gb2312"); request.setCharacterEncoding("gb2312"); PrintWriter out = response.getWriter(); this.doGet(request, response); out.flush(); out.close(); } /** * Initialization of the servlet. <br> * * @throws ServletException if an error occurs */ public void init() throws ServletException { // Put your code here } }
查询功能DeptList.java
package com.cn.query; import java.io.IOException; import java.io.PrintWriter; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class DeptList extends HttpServlet { /** * Constructor of the object. */ public DeptList() { super(); } /** * Destruction of the servlet. <br> */ public void destroy() { super.destroy(); // Just puts "destroy" string in log // Put your code here } /** * The doGet method of the servlet. <br> * * 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 { response.setContentType("text/html;charset=gb2312"); request.setCharacterEncoding("gb2312"); PrintWriter out = response.getWriter(); String id = request.getParameter("f_id"); //获取水果简称代号 Connection conn = null; //声明一个Connection对象，用来连接数据库 PreparedStatement pstmt = null; ResultSet rs = null; try { Class.forName("com.mysql.jdbc.Driver"); System.out.println("创建驱动成功！"); //连接数据库 conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test_db", "root", "123456"); System.out.println("连接数据库成功！"); String sql = "SELECT * FROM fruits"; pstmt = conn.prepareStatement(sql); // pstmt.setString(1, id); rs = pstmt.executeQuery(); } catch (ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } try { while(rs.next()){ out.print("水果简称代号:"+rs.getString(1)+"</br>"); out.print("水果编号:"+rs.getString(2)+"</br>"); out.print("水果名称:"+rs.getString(3)+"</br>"); out.print("水果价格:"+rs.getString(4)+"</br>"); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } out.flush(); out.close(); } /** * The doPost method of the servlet. <br> * * 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;charset=gb2312"); request.setCharacterEncoding("gb2312"); PrintWriter out = response.getWriter(); this.doGet(request, response); out.flush(); out.close(); } /** * Initialization of the servlet. <br> * * @throws ServletException if an error occurs */ public void init() throws ServletException { // Put your code here } }
相应的html页面放到一个上面：showById.html
<!DOCTYPE html> <html> <head> <title>showById.html</title> <meta name="keywords" content="keyword1,keyword2,keyword3"> <meta name="description" content="this is my page"> <meta name="content-type" content="text/html; charset=gb2312"> <!--<link rel="stylesheet" type="text/css" href="./styles.css">--> </head> <body> <form name="f1" id="f1" action="http://localhost:8080/JavaServlet/servlet/SearchEmployee" method="post"> <table border="0"> <tr> <td>水果名称:</td> <td><input type="text" name="f_name"></td> </tr> <tr> <td colspan="2" align="left"><input type="submit" value="查找"></td> </tr> </table> </form> <form name="f2" id="f2" action="http://localhost:8080/JavaServlet/servlet/DeptList" method="post"> <table border="0"> <tr> <td>所有水果:</td> <td colspan="2"><input type="submit" value="查看所有水果"></td> </tr> </table> </form> </body> </html>
编译和运行
编译之后运行Run as MyEclipse Server Application，报错说找不到jdbc的驱动，按照网上的说法，下载jdbc驱动，mysql-connector-java-5.1.42.zip，添加add Externel jar，在工程的lib下有，重新运行，结果还是找不到jdbc驱动，看到网上 有人说是版本不匹配导致的，后来重新下载了一个驱动mysql-connector-java-5.0.6-bin.jar，运行结果还是找不到，最后把驱动文件添加到tomcat目录下运行成功，后续运行只需要启动tomcat7就可以了。
到此运行成功，后续会考虑分页的显示问题，暂写到此。