05_HttpServletResponse_响应Html文档_显示书籍列表

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分析一个书籍管理系统

Book{ Id, Name, Price, Author, pubDate}

1. 建表：

CREATE TABLE `book` (  `id` int(11) NOT NULL AUTO_INCREMENT,  `name` varchar(50) DEFAULT NULL,  `price` double DEFAULT NULL,  `author` varchar(50) DEFAULT NULL,  `pubDate` date DEFAULT NULL,  PRIMARY KEY (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8;

2. 在项目中新建Book实体类：放于com.zhushen.entity包

package com.zhushen.entity;import java.util.Date;public class Book {    private int id;    private String name;    private double price;    private String author;    private Date pubDate;    public Book() {    }    public Book(String name, double price, String author, Date pubDate) {        super();        this.name = name;        this.price = price;        this.author = author;        this.pubDate = pubDate;    }    public Book(int id, String name, double price, String author, Date pubDate) {        super();        this.id = id;        this.name = name;        this.price = price;        this.author = author;        this.pubDate = pubDate;    }    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public double getPrice() {        return price;    }    public void setPrice(double price) {        this.price = price;    }    public String getAuthor() {        return author;    }    public void setAuthor(String author) {        this.author = author;    }    public Date getPubDate() {        return pubDate;    }    public void setPubDate(Date pubDate) {        this.pubDate = pubDate;    }}

3. 分析功能：先做显示所有书籍

先做书籍查询功能
1. 由于对书籍的操作有很多：如增加、修改、查询及删除等于数据库交互的操作
2. 所以将这些操作放于一个类中。取名BookDao
  DAO：data accesss object(数据访问对象)

4. 建一个util包:该包下存放连接数据库的工具类DBHelperForMysql

package com.zhushen.util;import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;public class DBHelperForMysql {    private String DBName;    private String User;    private String PassWord;    private Connection conn;    private PreparedStatement pst;    private ResultSet rs;    public DBHelperForMysql(String DBName, String User, String PassWord) {        super();        this.DBName = DBName;        this.User = User;        this.PassWord = PassWord;    }    /**     * 获得数据库连接     */    private void getConnection(){        try {            Class.forName("com.mysql.jdbc.Driver");            String url="jdbc:mysql://localhost:3306/"+DBName;            conn=DriverManager.getConnection(url,User,PassWord);        } catch (ClassNotFoundException e) {            e.printStackTrace();        } catch (SQLException e) {            e.printStackTrace();         }    }    /**     * 查询方法     * @param sql     * @param objects     * @return     */        public ResultSet executeQuery(String sql,Object...objects){            try {                this.getConnection();                pst=conn.prepareStatement(sql);                if(objects!=null){                    for(int i=0;i<objects.length;i++){                        pst.setObject(i+1, objects[i]);                    }                }                return rs=pst.executeQuery();            } catch (SQLException e) {                e.printStackTrace();            }            return null;        }    /**     * 更新--增加，修改，删除     * @param sql     * @param objects     * @return     */    public int executeUpdate(String sql,Object...objects){        try {            this.getConnection();            pst=conn.prepareStatement(sql);            if(objects!=null){                for(int i=0;i<objects.length;i++){                    pst.setObject(i+1, objects[i]);                }            }            return pst.executeUpdate();        } catch (SQLException e) {            e.printStackTrace();        }finally{            this.close();        }        return -1;    }    /**     * 关闭数据库连接     */        public void close(){            if(rs!=null){                try {                    rs.close();                } catch (SQLException e) {                    e.printStackTrace();                }            }            if(pst!=null){                try {                    pst.close();                } catch (SQLException e) {                    e.printStackTrace();                }            }            if(conn!=null){                try {                    conn.close();                } catch (SQLException e) {                    e.printStackTrace();                }            }        }}

5. 建一个dao包:该包下存放所有与数据库相关的操作的类BookDao

package com.zhushen.dao;import java.sql.ResultSet;import java.sql.SQLException;import java.util.ArrayList;import java.util.List;import com.zhushen.entity.Book;import com.zhushen.util.DBHelperForMysql;public class BookDao {//查询所有书籍    public List<Book> getAll(){        List<Book> list=new ArrayList<Book>();        //查询的操作        DBHelperForMysql DBhelper=new DBHelperForMysql("booksys", "root", "Code531182");        String sql="select * from book";        try {            ResultSet rs=DBhelper.executeQuery(sql);            while(rs.next()){                list.add(new Book(rs.getInt(1),rs.getString(2),rs.getDouble(3),                        rs.getString(4 ),rs.getDate(5)));            }        } catch (SQLException e) {            e.printStackTrace();        }finally{            DBhelper.close();        }        return list;    }}

6. 建一个servlet包，编写ListServlet类

package com.zhushen.servlet;import java.io.IOException;import java.io.PrintWriter;import java.text.SimpleDateFormat;import java.util.List;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.zhushen.dao.BookDao;import com.zhushen.entity.Book;public class ListServlet extends HttpServlet{    private static final long serialVersionUID = 1L;    private BookDao bookdao=new BookDao();@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp)        throws ServletException, IOException {    List<Book> list=bookdao.getAll();    resp.setCharacterEncoding("utf-8");    resp.setContentType("text/html;charset=utf-8");    PrintWriter os=resp.getWriter();    os.print("<html>");    os.print("<head>");    os.print("<title>");    os.print("书籍列表");    os.print("</title>");    os.print("</head>");    os.print("<body>");    os.print("<table align='center' width='80%'>");    os.print("<tr>");        os.print("<td>");        os.print("编号");        os.print("</td>");        os.print("<td>");        os.print("书名");        os.print("</td>");        os.print("<td>");        os.print("价格");        os.print("</td>");        os.print("<td>");        os.print("作者");        os.print("</td>");        os.print("<td>");        os.print("出版日期");        os.print("</td>");    os.print("</tr>");    if(list!=null){        for(int i=0;i<list.size();i++){            os.print("<tr>");            os.print("<td>");            os.print(list.get(i).getId());            os.print("</td>");            os.print("<td>");            os.print(list.get(i).getName());            os.print("</td>");            os.print("<td>");            os.print(list.get(i).getPrice());            os.print("</td>");            os.print("<td>");            os.print(list.get(i).getAuthor());            os.print("</td>");            os.print("<td>");            os.print(new SimpleDateFormat("yyyy-MM-dd").format(list.get(i).getPubDate()));            os.print("</td>");        os.print("</tr>");        }    }      os.print("</table>");    os.print("</body>");    os.print("</html>");}@Override    protected void doPost(HttpServletRequest req, HttpServletResponse resp)            throws ServletException, IOException {        this.doGet(req, resp);    }}

7. 部署web.xml文件

<servlet>        <servlet-name>listServlet</servlet-name>        <servlet-class>com.zhushen.servlet.ListServlet</servlet-class>     </servlet>     <servlet-mapping>        <servlet-name>listServlet</servlet-name>        <url-pattern>/list</url-pattern>     </servlet-mapping>

通过Http://localhost:8080/booksys/list访问

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