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完整的CRUD——javaweb

1，总体架构

　　index是进去的页面，

可以跳转Insert的增加页面，operatePerson是根据传进来的URI来判断增删改查的页面，

DbManager.java是封装的数据库操作类, Pagination.java是页脚的信息栏

2，index页面

    final int pageSize = 5;//一页显示多少纪录
    int pageNum = 1;//当前页数
    int pageCount = 1;//总页数
    int recordCount = 0;//总记录数

    <form action="operatePerson.jsp" method="post">
        <table border="1">
            <%
                for(; resultSet.next();){
                    out.println("<tr>");
                    String name = resultSet.getString("name");
                    out.println("<td>" + name + "</td>");
                    out.println("<td>" + resultSet.getString("age") + "</td>");
                    out.println("<td>" + resultSet.getString("sex") + "</td>");
                    out.println("<td><a href='operatePerson.jsp?action=delete&name=" + name +"'>删除</a></td>");
                    out.println("<td><a href='operatePerson.jsp?action=edit&name=" + name +"'>修改</a></td>");
                    out.println("</tr>");
                }
            %>
        </table>
        <%=Pagination.getPagination(pageNum, pageCount
                    , recordCount, request.getRequestURI()) %>

画出表，包括页脚，（上面的form其实没有什么用

分页技术使用数据库的 select * from person limit ?,? ----意思是从哪条开始（不包括这一条）的 n条记录

问号使用preparedStatement语句来实现

代码：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ page import="java.sql.DriverManager"%>
<%@ page import="java.sql.Connection"%>
<%@ page import="java.sql.Statement"%>
<%@ page import="java.sql.ResultSet"%>
<%@ page import="java.sql.PreparedStatement"%>
<%@ page import="java.sql.SQLException"%>
<%@ page import="testPackage.DbManager" %>
<%@ page import="testPackage.Pagination" %>
<%
    String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->
</head>

<%
    final int pageSize = 5;//一页显示多少纪录
    int pageNum = 1;//当前页数
    int pageCount = 1;//总页数
    int recordCount = 0;
    try{//当前页数
        pageNum = Integer.parseInt(request.getParameter("pageNum"));
        System.out.println("0000:" + pageNum);
    }catch(Exception e){}
    String sql = null;
    Connection con = null;
    PreparedStatement preparedStatement = null;
    ResultSet resultSet = null;
    try{
        sql = "select count(*) from person";
        recordCount = DbManager.getCount(sql);
        pageCount = (recordCount + pageSize - 1) / pageSize;
        int startRecord = (pageNum - 1) * pageSize;
        sql = "select * from person limit ?,?";
        con = DbManager.getConnection();
        preparedStatement = con.prepareStatement(sql);
        DbManager.setParams(preparedStatement, startRecord, pageSize);
        resultSet = preparedStatement.executeQuery();
%>
<body>
    <a href="Insert.jsp">新建一个</a>
    <form action="operatePerson.jsp" method="post">
        <table border="1">
            <%
                for(; resultSet.next();){
                    out.println("<tr>");
                    String name = resultSet.getString("name");
                    out.println("<td>" + name + "</td>");
                    out.println("<td>" + resultSet.getString("age") + "</td>");
                    out.println("<td>" + resultSet.getString("sex") + "</td>");
                    out.println("<td><a href='operatePerson.jsp?action=delete&name=" + name +"'>删除</a></td>");
                    out.println("<td><a href='operatePerson.jsp?action=edit&name=" + name +"'>修改</a></td>");
                    out.println("</tr>");
                }
            %>
        </table>
        <%=Pagination.getPagination(pageNum, pageCount
                    , recordCount, request.getRequestURI()) %>
        <br/>
        <%=pageNum %>
    </form>
    <%
    }catch(SQLException e1){
        out.println("0001" + e1.getMessage());
    }
    finally {
        if (resultSet != null)
            resultSet.close();
        if (preparedStatement != null)
            preparedStatement.close();
        if (con != null)
            con.close();
    }
    %>
</body>
</html>

View Code

2，operatePerson.jsp页面

我写的时候没有使用DbManager类，在里面的增删改都用了原始的操作

    request.setCharacterEncoding("UTF-8");
    response.setCharacterEncoding("UTF-8");//一定要
    String action = request.getParameter("action");//先接受是什么操作

增：request.getPararmeter("name...")通过这个方法来获得表传进来的数据

删：request.getPararmeter("name")通过这个方法来获得uri传进来的paramer

改：request.getPararmeter("name")通过这个方法来获得uri传进来的paramer，（我设计的时候没有完善好，默认他们不能有同名，所以不能改名字

　　request.setAttribute("name", resultSet.getString("name")//把传进来的参数穿进去request里面，用forward转向到insert的页面在，那样insert可以从request里面提取数据（同时也把"save"信息传过去)，和真正的插入有了区别

　　在insert会判断是save的传递，把数据传回来operate页面，做真正的修改

3，insert页面

会根据传过来的action判断是插入还是修改，以此来修改uri，form表给的提交方式要改为post ,因为这样表格的内容就不能形象uri的传递，

value="${name}"的时候，在修改的时候会显示值，注意：el表达式，${name}或者${requestScope.name}而不是${request.name}

4,Pagination.java

　　页脚，用StringBuffer类，append字符串

5，DbManager.java

　　数据库管理类

public static Connection getConnection(String dbName, String userName,String password)

public static Connection getConnection()　　　　　　　　　　　　　　　　　　　　　　　　　　//获得con对象

public static void setParams(PreparedStatement preparedStatement,Object... params) //把preparedStatement放进去，发若干个参数，preparedStatement.setInt.....之类的

public static int executeUpdate(String sql)

public static int executeUpdate(String sql, Object... params) 　　　　　　　　　　　　　　//对上面方法的封装，穿进去sql的字符串就行了

源码：

DbManager

package testPackage;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Types;

public class DbManager {
    public static Connection getConnection() throws SQLException,
            ClassNotFoundException {
        return getConnection("test", "kooing", "");
    }

    public static Connection getConnection(String dbName, String userName,
            String password) throws SQLException, ClassNotFoundException {
        String url = "jdbc:mysql://localhost:3306/" + dbName;
        Class.forName("com.mysql.jdbc.Driver");
        Connection con = DriverManager.getConnection(url);
        return con;
    }

    public static void setParams(PreparedStatement preparedStatement,
            Object... params) throws SQLException {
        for (int i = 1; i <= params.length; i++) {
            Object param = params[i - 1];
            if (param == null) {
                preparedStatement.setNull(i, Types.NULL);
            } else if (param instanceof Integer) {
                preparedStatement.setInt(i, (Integer) param);
            } else if (param instanceof String) {
                preparedStatement.setString(i, (String) param);
            }
        }
    }

    public static int executeUpdate(String sql) throws SQLException,
            ClassNotFoundException {
        return executeUpdate(sql, new Object[] {});
    }

    public static int executeUpdate(String sql, Object... params)
            throws SQLException, ClassNotFoundException {
        Connection con = null;
        PreparedStatement preparedStatement = null;
        try {
            con = getConnection();
            preparedStatement = con.prepareStatement(sql);
            setParams(preparedStatement, params);
            return preparedStatement.executeUpdate();
        } finally {
            if (preparedStatement != null)
                preparedStatement.close();
            if (con != null)
                con.close();
        }
    }

    public static int getCount(String sql) throws SQLException,
            ClassNotFoundException {
        Connection con = null;
        Statement statement = null;
        ResultSet rs = null;
        try {
            con = getConnection();
            statement = con.createStatement();
            rs = statement.executeQuery(sql);
            rs.next();
            return rs.getInt(1);
        } finally {
            if (rs != null)
                rs.close();
            if (statement != null)
                statement.close();
            if (con != null)
                con.close();
        }
    }
}

View Code

Pagination

package testPackage;

public class Pagination {
    public static String getPagination(int pageNum, int pageCount,
            int recordCount, String pageUrl) {
        String url = pageUrl.contains("?") ? pageUrl : pageUrl + "?";
        if (!url.endsWith("?") && !url.endsWith("&")) {
            url += "&";
        }
        StringBuffer buffer = new StringBuffer();
        buffer.append("第  " + pageNum + "/" + pageCount + "页，共" + recordCount
                + "纪录。");
        buffer.append(pageNum == 1 ? "第一页" : "<a href='" + url
                + "pageNum=1'>第一页</a>");
        // buffer.append(pageNum == 1 ? "第一页" : "<a href='" + url + "pageNum=" +
        // 1
        // + "'>第一页</a>");

        buffer.append(pageNum == 1 ? "上一页" : "<a href='" + url + "pageNum="
                + (pageNum - 1) + "'>上一页</a>");

        buffer.append(pageNum == pageCount ? "下一页" : "<a href='" + url
                + "pageNum=" + (pageNum + 1) + "'>下一页</a>");

        buffer.append(pageNum == pageCount ? "最后一页" : "<a href='" + url
                + "pageNum=" + pageCount + "'>最后一页</a>");
        return buffer.toString();
    }
}

View Code

index

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ page import="java.sql.DriverManager"%>
<%@ page import="java.sql.Connection"%>
<%@ page import="java.sql.Statement"%>
<%@ page import="java.sql.ResultSet"%>
<%@ page import="java.sql.PreparedStatement"%>
<%@ page import="java.sql.SQLException"%>
<%@ page import="testPackage.DbManager" %>
<%@ page import="testPackage.Pagination" %>
<%
    String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->
</head>

<%
    final int pageSize = 5;//一页显示多少纪录
    int pageNum = 1;//当前页数
    int pageCount = 1;//总页数
    int recordCount = 0;
    try{//当前页数
        pageNum = Integer.parseInt(request.getParameter("pageNum"));
        System.out.println("0000:" + pageNum);
    }catch(Exception e){}
    String sql = null;
    Connection con = null;
    PreparedStatement preparedStatement = null;
    ResultSet resultSet = null;
    try{
        sql = "select count(*) from person";
        recordCount = DbManager.getCount(sql);
        pageCount = (recordCount + pageSize - 1) / pageSize;
        int startRecord = (pageNum - 1) * pageSize;
        sql = "select * from person limit ?,?";
        con = DbManager.getConnection();
        preparedStatement = con.prepareStatement(sql);
        DbManager.setParams(preparedStatement, startRecord, pageSize);
        resultSet = preparedStatement.executeQuery();
%>
<body>
    <a href="Insert.jsp">新建一个</a>
    <form action="operatePerson.jsp" method="post">
        <table border="1">
            <%
                for(; resultSet.next();){
                    out.println("<tr>");
                    String name = resultSet.getString("name");
                    out.println("<td>" + name + "</td>");
                    out.println("<td>" + resultSet.getString("age") + "</td>");
                    out.println("<td>" + resultSet.getString("sex") + "</td>");
                    out.println("<td><a href='operatePerson.jsp?action=delete&name=" + name +"'>删除</a></td>");
                    out.println("<td><a href='operatePerson.jsp?action=edit&name=" + name +"'>修改</a></td>");
                    out.println("</tr>");
                }
            %>
        </table>
        <%=Pagination.getPagination(pageNum, pageCount
                    , recordCount, request.getRequestURI()) %>
        <br/>
        <%=pageNum %>
    </form>
    <%
    }catch(SQLException e1){
        out.println("0001" + e1.getMessage());
    }
    finally {
        if (resultSet != null)
            resultSet.close();
        if (preparedStatement != null)
            preparedStatement.close();
        if (con != null)
            con.close();
    }
    %>
</body>
</html>

View Code

operate

<%@page import="java.sql.DriverManager"%>
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ page import="java.sql.DriverManager"%>
<%@ page import="java.sql.Connection"%>
<%@ page import="java.sql.Statement"%>
<%@ page import="java.sql.ResultSet"%>
<%
    String path = request.getContextPath();
    String basePath = request.getScheme() + "://"
    + request.getServerName() + ":" + request.getServerPort()
    + path + "/";
%>
<%
    request.setCharacterEncoding("UTF-8");
    response.setCharacterEncoding("UTF-8");
    String action = request.getParameter("action");
    String sql = null;
    if ("add".equals(action)) {
        String name = request.getParameter("name");
        int age = Integer.parseInt(request.getParameter("age"));
        String sex = request.getParameter("sex");
        sql = "insert into person values('" + name + "','" + age
        + "','" + sex + "')";
        try {
    Class.forName("com.mysql.jdbc.Driver");
    Connection con = DriverManager.getConnection(
    "jdbc:mysql://localhost:3306/test", "kooing", "");
    Statement sm = con.createStatement();
    int resultSet = sm.executeUpdate(sql);
    out.println(sql);
        } catch (Exception e) {

        }
    }
    if ("delete".equals(action)) {
        String name = request.getParameter("name");
        System.out.println(name);
        sql = "delete from person where name = '" + name + "'";
        try {
    Class.forName("com.mysql.jdbc.Driver");
    Connection con = DriverManager.getConnection(
    "jdbc:mysql://localhost:3306/test", "kooing", "");
    Statement sm = con.createStatement();
    int resultSet = sm.executeUpdate(sql);
    out.println(sql);
        } catch (Exception e) {

        }
    }
    if ("edit".equals(action)) {
        try {
    String name = request.getParameter("name");
    sql = "select * from person where name ='" + name + "'";
    Class.forName("com.mysql.jdbc.Driver");
    Connection con = DriverManager.getConnection(
    "jdbc:mysql://localhost:3306/test", "kooing", "");
    Statement sm = con.createStatement();
    ResultSet resultSet = sm.executeQuery(sql);
    out.println(sql);
    resultSet.next();
    request.setAttribute("name", resultSet.getString("name"));
    request.setAttribute("age", resultSet.getString("age"));
    request.setAttribute("sex", resultSet.getString("sex"));
    request.setAttribute("action", action);
    request.getRequestDispatcher("Insert.jsp").forward(request,
    response);
        } catch (Exception e) {
        }
    }
    if("save".equals(action)){
        String name = request.getParameter("name");
        int age = Integer.parseInt(request.getParameter("age"));
        String sex = request.getParameter("sex");
        sql = "update person set " 
                + "name='" + name
                + "',age='" + age
                + "',sex='" + sex + "' where name ='" + name +"'";
        System.out.println(sql);
        Class.forName("com.mysql.jdbc.Driver");
        Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test",
        "kooing", "");
        Statement sm = con.createStatement();
        int result = sm.executeUpdate(sql);
    }
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>My JSP 'operatePerson.jsp' starting page</title>

<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->

</head>

<body>
    This is my JSP page.
    <br>
    <a href="index.jsp">主页</a>
</body>
</html>

View Code

insert

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'Insert.jsp' starting page</title>
    
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->

  </head>
  
  <body>
      <%
          String myAction = (String)request.getAttribute("action");
          myAction = myAction == null? "add" : "save";
          System.out.println(myAction);
          System.out.println(request.getAttribute("name"));
          System.out.println(request.getAttribute("age"));
          System.out.println(request.getAttribute("sex"));
      %>
    <form action="operatePerson.jsp?action=<%=myAction %>" method="post">
        姓名<input type="text" name="name" value="${name }"><br/>
        年龄<input type="text" name="age" value="${age }"><br/>
        性别<input type="text" name="sex" value="${sex }"><br/>
        <input type="submit">
    </form>
  </body>
</html>

View Code

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原文地址：https://www.cnblogs.com/vhyc/p/6674175.html