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IntelliJ IDEA开发Web应用程式实现数据增删查改

2017-05-18 15:17 316 查看
本文分两部分：

1. Intellij Idea创建Web应用程式；

2. 开发一个具备增删查改的WEB应用程序并部署到本地服务器。

原料：
Intellij IDE
JDK
Tomcat
Mysql
Navicat for MySQL
浏览器
开发相关jar包（c3p0，commons-beanutils，commons-collections，commons-dbutils，commons-logging，jstl，mchange-commons-java，mysql-connector-java）


新建及配置工程

File -> New Project -> 输入项目名称“Demos” ，选择Project SDK为1.7 -> Next -> Finish。

鼠标点中项目名称demos -> 右键选择New，选择Module ->

输入Module名称“firstweb” -> 点击Next->

勾选“Web Application” -> 确认已勾选“Create web.xml” -> Finish。

在web/WEB-INF下创建两个文件夹：classes和lib，classes用来存放编译后输出的class文件，lib用于存放第三方jar包。

配置文件夹路径

File -> Project Structure (快捷键：Ctrl + Shift + Alt + S) -> 选择Module ：

选择 Paths -> 选择”Use module compile output path” -> 将Output path和Test output path都选择刚刚创建的classes文件夹。

接着选择Dependencies -> 将Module SDK选择为1.7 -> 点击右边的“+”号 -> 选择1 “Jars or Directories”

-> 选择刚刚创建的lib文件夹 -> 选择“jar directory” -> 接着返回一路OK就行了。

打开菜单Run -> 选择Edit Configuration ->

点击“+”号 -> 选择“Tomcat Server” -> 选择“Local”->

在”Name”处输入新的服务名，点击”Application server”后面的”Configure…”，弹出Tomcat Server窗口，选择本地安装的Tomcat目录 -> OK

在”Run/Debug Configurations”窗口的”Server”选项板中，取消勾选”After launch”，设置”HTTP port”和”JMX port”（默认值即可），点击 Apply -> OK， 至此Tomcat配置完成。

在Tomcat中部署并运行项目

Run -> Edit Configurations，进入”Run/Debug Configurations”窗口 -> 选择刚刚建立的Tomcat容器 -> 选择Deployment -> 点击右边的“+”号 -> 选择Artifact，

选择web项目 -> Application context可以填“/hello”> OK（这个hello可以替换成你想要的名字，这个名字是浏览器访问时的程序根目录，/代表tomcat服务器根目录）。

实现添加用户

到这里，准备工作完成，我们开始写代码了：

index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<html>
<head>
<title>主页</title>
</head>
<frameset rows="20%,*">
<frame src="<c:url value='/top.jsp'/>" name="top"/>
<frame src="<c:url value='/welcome.jsp'/>" name="main"/>
</frameset>
</html>


index里面包含了top.jsp，为了操作方便，top.jsp是用来和用户交互的，welcome则负责数据的显示。默认welcome没数据，name=”main”表示主页面是这个框架。

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
<!-- 他的作用是为本页面所有的表单和超链接指定显示内容的框架-->
<base target="main">
<title>My JSP 'top.jsp' starting page</title>
</head>
<body style="text-align: center;">
<h1>客户关系管理系统</h1>
<a href="<c:url value='/add.jsp'/>">添加客户</a>
<a href="<c:url value='/CustomerServlet?method=findAll'/>">查询客户</a>
<a href="<c:url value='/query.jsp'/>">高级搜索</a>

</body>
</html>


welcome.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>

</body>
</html>


我们看到早top.jsp里面有三个操作，分别是添加用户，查询用户，高级搜索，我们从添加用户开始实现，因为数据库一开始是没有数据的。c:url是jstl表达式，这里不便多数，点击添加用户跳转到add.jsp

add.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<h3 align="center">添加客户</h3>

<form action="<c:url value='/CustomerServlet'/>" method="post">
<input type="hidden" name="method" value="add">
<table border="1" align="center" width="40%" style="margin-left: 100px">
<tr>
<td width="100px">客户名称</td>
<td width="40%">
<input type="text" name="name"/>
</td>
<td align="left">
<label id="nameError" class="error"> </label>
</td>
</tr>
<tr>
<td>客户性别</td>
<td>
<input type="radio" name="gender" value="male" id="male"/>
<label for="male">男</label>
<input type="radio" name="gender" value="female" id="female"/>
<label for="female">女</label>
</td>
<td>
<label id="genderError" class="error"> </label>
</td>
</tr>
<tr>
<td>手机</td>
<td>
<input type="text" name="phone" id="phone">
</td>
<td>
<label id="phoneError" class="error"> :</label>
</td>
</tr>
<tr>
<td>邮箱</td>
<td>
<input type="text" name="email" id="email"/>
</td>
<td>
<label id="emailError" class="error"></label>
</td>
</tr>
<tr>
<td>描述</td>
<td>
<textarea rows="5" cols="30" name="description"></textarea>
</td>
<td>
<label id="discriptionError" class="error"> </label>
</td>
</tr>
<tr>
<td></td>
<td>
<input type="submit" name="submit"/>
<input type="reset" name="reset"/>
</td>
</tr>
</table>
</form>

</body>
</html>


页面里面是一个表单，然后我设置了一个表单提交时的隐藏项：method:add，也就是说提交到/CustomerServlet’的时候会把这个字段带上去，后台可以通过获取到这个字段判断要执行什么操作。这样做是为了方便后台代码统一管理，不至于看代码的时候找不到入口。

我们看到提交到了/CustomerServlet这里面，那我们就来新建一个Servlet：

src右击->new->servlet ，name填CustomerServlet，package填servlet。这里我写了一个BaseServlet.，让这个servlet集成BaseServlet，BaseServlet帮我们做好了方法反射。

我们这里把BaseServlet相关的贴出来。

BaseServlet.java

import servlet.GetRequest;
import java.io.IOException;
import java.lang.reflect.Method;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class BaseServlet extends HttpServlet {
public BaseServlet() {
}

public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
if(((HttpServletRequest)request).getMethod().equalsIgnoreCase("get")) {
if(!(request instanceof GetRequest)) {
request = new GetRequest((HttpServletRequest)request);
}
} else {
((HttpServletRequest)request).setCharacterEncoding("utf-8");
}

response.setContentType("text/html;charset=UTF-8");
String methodName = ((HttpServletRequest)request).getParameter("method");
Method method = null;

try {
method = this.getClass().getMethod(methodName, new Class[]{HttpServletRequest.class, HttpServletResponse.class});
} catch (Exception var10) {
throw new RuntimeException("您要调用的方法：" + methodName + "它不存在！", var10);
}

try {
String e = (String)method.invoke(this, new Object[]{request, response});
if(e != null && !e.trim().isEmpty()) {
int index = e.indexOf(":");
if(index == -1) {
((HttpServletRequest)request).getRequestDispatcher(e).forward((ServletRequest)request, response);
} else {
String start = e.substring(0, index);
String path = e.substring(index + 1);
if(start.equals("f")) {
((HttpServletRequest)request).getRequestDispatcher(path).forward((ServletRequest)request, response);
} else if(start.equals("r")) {
response.sendRedirect(((HttpServletRequest)request).getContextPath() + path);
}
}
}

} catch (Exception var9) {
throw new RuntimeException(var9);
}
}
}


GetRequest .java

import java.io.UnsupportedEncodingException;
import java.util.Iterator;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;

public class GetRequest extends HttpServletRequestWrapper {
private HttpServletRequest request;

public GetRequest(HttpServletRequest request) {
super(request);
this.request = request;
}

public String getParameter(String name) {
String value = this.request.getParameter(name);
if(value == null) {
return null;
} else {
try {
return new String(value.getBytes("ISO-8859-1"), "UTF-8");
} catch (UnsupportedEncodingException var4) {
throw new RuntimeException(var4);
}
}
}

public Map getParameterMap() {
Map map = this.request.getParameterMap();
if(map == null) {
return map;
} else {
Iterator var3 = map.keySet().iterator();

while(var3.hasNext()) {
String key = (String)var3.next();
String[] values = (String[])map.get(key);

for(int i = 0; i < values.length; ++i) {
try {
values[i] = new String(values[i].getBytes("ISO-8859-1"), "UTF-8");
} catch (UnsupportedEncodingException var7) {
throw new RuntimeException(var7);
}
}
}

return map;
}
}
}


接下来我们实现add方法了：

public class ConstomerServlet extends BaseServlet {
private CustomerServier customerService= new CustomerServier();

public String add(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
Customer customer = CommonUtils.toBean(request.getParameterMap(), Customer.class);
customer.setId(CommonUtils.uuid());

customerService.add(customer);
request.setAttribute("msg", "恭喜，成功添加客户");
return "/msg.jsp";
}
}


这里我们需要新建一个公共显示的页面msg.jsp，这个页面的工作就是把msg提取出来并显示。

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<h1 style="color:green;" align="center">${msg}</h1>

</body>
</html>


然后方法实现里面要求我们建一个Model保存用户提交的数据，这里用了一个库，这个是commons.beanutils，同时我们新建两个文件：CommonUtils.java，DateConverter.java。

其实像上面这些通用的组件我们可以打包成一个jar包保存起来。

CommonUtils.java

import commons.DateConverter;
import java.util.Date;
import java.util.Map;
import java.util.UUID;
import org.apache.commons.beanutils.BeanUtils;
import org.apache.commons.beanutils.ConvertUtils;

public class CommonUtils {
public CommonUtils() {
}

public static String uuid() {
return UUID.randomUUID().toString().replace("-", "").toUpperCase();
}

public static <T> T toBean(Map map, Class<T> clazz) {
try {
Object e = clazz.newInstance();
ConvertUtils.register(new DateConverter(), Date.class);
BeanUtils.populate(e, map);
return e;
} catch (Exception var3) {
throw new RuntimeException(var3);
}
}
}


DateConverter.java

import java.text.ParseException;
import java.text.SimpleDateFormat;
import org.apache.commons.beanutils.Converter;

public class DateConverter implements Converter {
public DateConverter() {
}

public Object convert(Class type, Object value) {
if(value == null) {
return null;
} else if(!(value instanceof String)) {
return value;
} else {
String val = (String)value;
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");

try {
return sdf.parse(val);
} catch (ParseException var6) {
throw new RuntimeException(var6);
}
}
}
}


Customer.java

public class Customer
{
private String id;
private String name;
private String gender;
private String phone;
private String email;
private String description;

public String getId() {
return id;
}

public void setId(String id) {
this.id = id;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public String getGender() {
return gender;
}

public void setGender(String gender) {
this.gender = gender;
}

public String getPhone() {
return phone;
}

public void setPhone(String phone) {
this.phone = phone;
}

public String getEmail() {
return email;
}

public void setEmail(String email) {
this.email = email;
}

public String getDescription() {
return description;
}

public void setDescription(String description) {
this.description = description;
}
}


为了让逻辑更清晰，我们新建一个Service类来处理业务逻辑

CustomerServier .java

public class CustomerServier {
CustomerDao customerDao = new CustomerDao();

public void add(Customer customer)
{
customerDao.add(customer);
}
}


数据库专门建一个类来处理，CustomerDao

CustomerDao.java

public class CustomerDao {

private QueryRunner qr = new TxQueryRunner();

public void add(Customer c) {
try {
String sql = "insert into t_customer values(?,?,?,?,?,?)";
Object[] params = {c.getId(), c.getName(), c.getGender(),
c.getPhone(), c.getEmail(), c.getDescription()};

qr.update(sql, params);
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}


我们这里需要新建两个工具类：JdbcUtils，TxQueryRunner

TxQueryRunner.java

import jdbc.JdbcUtils;
import java.sql.Connection;
import java.sql.SQLException;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.ResultSetHandler;

public class TxQueryRunner extends QueryRunner {
public TxQueryRunner() {
}

public int[] batch(String sql, Object[][] params) throws SQLException {
Connection con = JdbcUtils.getConnection();
int[] result = super.batch(con, sql, params);
JdbcUtils.releaseConnection(con);
return result;
}

public <T> T query(String sql, ResultSetHandler<T> rsh, Object... params) throws SQLException {
Connection con = JdbcUtils.getConnection();
Object result = super.query(con, sql, rsh, params);
JdbcUtils.releaseConnection(con);
return result;
}

public <T> T query(String sql, ResultSetHandler<T> rsh) throws SQLException {
Connection con = JdbcUtils.getConnection();
Object result = super.query(con, sql, rsh);
JdbcUtils.releaseConnection(con);
return result;
}

public int update(String sql) throws SQLException {
Connection con = JdbcUtils.getConnection();
int result = super.update(con, sql);
JdbcUtils.releaseConnection(con);
return result;
}

public int update(String sql, Object param) throws SQLException {
Connection con = JdbcUtils.getConnection();
int result = super.update(con, sql, param);
JdbcUtils.releaseConnection(con);
return result;
}

public int update(String sql, Object... params) throws SQLException {
Connection con = JdbcUtils.getConnection();
int result = super.update(con, sql, params);
JdbcUtils.releaseConnection(con);
return result;
}
}


从这点可以看出做Web开发，有一个自己的工具类组件库是多么重要。JdbcUtils用到了数据库连接池c3p0，那么我们要在src目录下新建一个xml文件来配置一把

JdbcUtils.java

import com.mchange.v2.c3p0.ComboPooledDataSource;
import java.sql.Connection;
import java.sql.SQLException;
import javax.sql.DataSource;

public class JdbcUtils {
private static DataSource ds = new ComboPooledDataSource();
private static ThreadLocal<Connection> tl = new ThreadLocal();

public JdbcUtils() {
}

public static DataSource getDataSource() {
return ds;
}

public static Connection getConnection() throws SQLException {
Connection con = (Connection)tl.get();
return con != null?con:ds.getConnection();
}

public static void beginTransaction() throws SQLException {
Connection con = (Connection)tl.get();
if(con != null) {
throw new SQLException("已经开启了事务，不能重复开启！");
} else {
con = ds.getConnection();
con.setAutoCommit(false);
tl.set(con);
}
}

public static void commitTransaction() throws SQLException {
Connection con = (Connection)tl.get();
if(con == null) {
throw new SQLException("没有事务不能提交！");
} else {
con.commit();
con.close();
con = null;
tl.remove();
}
}

public static void rollbackTransaction() throws SQLException {
Connection con = (Connection)tl.get();
if(con == null) {
throw new SQLException("没有事务不能回滚！");
} else {
con.rollback();
con.close();
con = null;
tl.remove();
}
}

public static void releaseConnection(Connection connection) throws SQLException {
Connection con = (Connection)tl.get();
if(connection != con && connection != null && !connection.isClosed()) {
connection.close();
}

}
}


c3p0-config.xml

这个是我的数据库配置，具体配置根据每个人电脑不同有所变化。至于里面具体字段代表的含义我就不一一介绍了。

<?xml version="1.0" encoding="utf-8" ?>
<c3p0-config>
<default-config>
<property name="jdbcUrl">jdbc:mysql://localhost:3306/customer</property>
<property name="driverClass">com.mysql.jdbc.Driver</property>
<property name="user">root</property>
<property name="password">root</property>
<property name="acquireIncrement">3</property>
<property name="initialPoolSize">10</property>
<property name="minPoolSize">2</property>
<property name="maxPoolSize">10</property>
</default-config>
</c3p0-config>


到这里，我们新建客户的操作就做好了，来运行一下看看效果。运行就是那个播放键。

好了，效果出来了，我们新建一个也成功了。一看数据库，确实插入进去了。有同学会说，数据库的代码还没贴出来呢？好吧，那我把数据库设计的表贴出来吧。。。。

t_customer.sql

/*
Navicat MySQL Data Transfer

Source Server         : larsonconn
Source Server Version : 50520
Source Host           : localhost:3306
Source Database       : customer

Target Server Type    : MYSQL
Target Server Version : 50520
File Encoding         : 65001

Date: 2017-05-18 14:54:29
*/

SET FOREIGN_KEY_CHECKS=0;

-- ----------------------------
-- Table structure for `t_customer`
-- ----------------------------
DROP TABLE IF EXISTS `t_customer`;
CREATE TABLE `t_customer` (
`id` varchar(50) NOT NULL,
`name` varchar(50) DEFAULT NULL,
`gender` varchar(20) DEFAULT NULL,
`phone` varchar(50) DEFAULT NULL,
`email` varchar(50) DEFAULT NULL,
`description` varchar(50) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;


实现查询

我们看top.jsp是这样写的

那门需要在servlet里面实现这个findAll方法：

public String findAll(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
/*
*1.获取页面传递的pc
* 2.给定pr的值
* 3.使用pc和pr调用service方法，得到pageBean，保存到request域
* 4.转发到list.jsp
*/
/*
* 1.得到pc
*   如果pc参数不存在，说明pc＝1
*   如果pc参数存在，需要转换成int类型
*/
int pc=getPc(request);

int pr=10;//给定pr的值，每页10行纪录

PageBean<Customer> pb= customerService.findAll(pc,pr);
pb.setUrl(getUrl(request));

request.setAttribute("pb",pb);

return "f:/list.jsp";
}


因为使用了分页查询，所以我们需要再建一个Bean，

PageBean.java

public class PageBean<Object>
{
private int pc;//当前页码page code
//private int tp;//总页数total pages
private int tr;//总纪录数tatal records
private int pr;//每页纪录数page records
private List<Object> beanList;//当前页的纪录
private String url;

public String getUrl() {
return url;
}

public void setUrl(String url) {
this.url = url;
}

public int getPc() {
return pc;
}

public void setPc(int pc) {
this.pc = pc;
}

public int getTp()
{
int tp=tr/pr;
return tr % pr == 0 ? tp : tp + 1 ;
}

public int getTr() {
return tr;
}

public void setTr(int tr) {
this.tr = tr;
}

public int getPr() {
return pr;
}

public void setPr(int pr) {
this.pr = pr;
}

public List<Object> getBeanList() {
return beanList;
}

public void setBeanList(List<Object> beanList) {
this.beanList = beanList;
}
}


然后再service实现findAll方法：

public PageBean<Customer> findAll(int pc, int pr) {
return customerDao.findAll(pc,pr);
}


然后是Dao层实现：先查询有多少条记录，记录多的时候就需要分页。使用limit指令实现。

public PageBean<Customer> findAll(int pc, int pr) {
try {
/*
*1.他需要创建pageBean对象pb
* 2.设置pb的pc和pr
* 3.得到tr，设置给pb
* 4.得到beanList设置给pb
* 最后返回给pb
*/
PageBean<Customer> pb = new PageBean<>();
pb.setPc(pc);
pb.setPr(pr);

String sql = "select count(*) from t_customer";
Number number = (Number) qr.query(sql, new ScalarHandler<>());

int tr = number.intValue();
pb.setTr(tr);

sql = "select * from t_customer order by name limit ?,?";
Object[] params = {(pc - 1) * pr, pr};
List<Customer> beanList = qr.query(sql, new BeanListHandler<>(Customer.class), params);

pb.setBeanList(beanList);

return pb;
} catch (Exception e) {
throw new RuntimeException(e);
}
}


现在我们拿到数据了，需要把这些数据显示出来，我们新建一个jsp用来显示这些数据：

list.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
<title>客户列表</title>
</head>
<body>
<h3 align="center" >客户列表</h3>
<table border="1" width="70%" align="center">
<tr>
<th>客户姓名</th>
<th>性别</th>
<th>手机</th>
<th>邮箱</th>
<th>描述</th>
<th>操作</th>
</tr>
<c:forEach items="${pb.beanList}" var="cstm">
<tr>
<td>${cstm.name}</td>
<td>${cstm.gender}</td>
<td>${cstm.phone}</td>
<td>${cstm.email}</td>
<td>${cstm.description}</td>
<td>
<a href="<c:url value='/CustomerServlet?method=preEdit&id=${cstm.id}'/> ">编辑</a>
<a href="<c:url value='/CustomerServlet?method=delete&id=${cstm.id}'/> ">删除</a>
</td>
</tr>
</c:forEach>
</table>
<br/>
<center>
第${pb.pc}页/共${pb.tp}页
<a href="${pb.url}&pc=1">首页</a>
<c:if test="${pb.pc>1}">
<a href="${pb.url}&pc=${pb.pc-1}">上一页</a>
</c:if>

<c:choose>
<c:when test="${pb.tp<=10}">
<c:set var="begin" value="1"/>
<c:set var="end" value="${pb.tp}"/>
</c:when>
<c:otherwise>
<c:set var="begin" value="${pb.pc-5}"/>
<c:set var="end" value="${pb.pc+4}"/>
<%--头溢出--%>
<c:if test="${begin<1}">
<c:set var="begin" value="1"/>
<c:set var="end" value="10"/>
</c:if>
<%--尾溢出--%>
<c:if test="${end>pb.tp}">
<c:set var="end" value="${pb.tp}"/>
<c:set var="begin" value="${pb.tp-9}"/>
</c:if>
</c:otherwise>
</c:choose>

<%--循环遍历页码列表--%>
<c:forEach var="i" begin="${begin}" end="${end}">
<c:choose>
<c:when test="${i eq pb.pc}">
[${i}]
</c:when>
<c:otherwise>
<a href="${pb.url}&pc=${i}">[${i}]</a>
</c:otherwise>
</c:choose>

</c:forEach>

<c:if test="${pb.pc<pb.tp}">
<a href="${pb.url}&pc=${pb.pc+1}">下一页</a>
</c:if>
<a href="${pb.url}&pc=${pb.tp}">尾页</a>

</center>

</body>
</html>


好了，list.jsp从传入的对象里面读取到数据并显示出来，到这里一个查询功能就实现了。

那查询做完了，我们来做一下高级查询，高级查询就是可以指定信息查询，从top页面进入，看到有/query.jsp，那我们建一个/query.jsp

/query.jsp’

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<html>
<head>
<title></title>
</head>
<body>
<h3 align="center">高级搜索</h3>
<form action="<c:url value="/CustomerServlet"/>" method="get">
<input type="hidden" name="method" value="query">
<table border="0" align="center" width="40%" style="margin-left: 100px">
<tr>
<td width="100px">客户名称</td>
<td width="40%">
<input type="text" name="name">
</td>
</tr>
<tr>
<td>客户性别</td>
<td>
<select name="gender">
<option value="">==请选择性别==</option>
<option value="male">male</option>
<option value="female">female</option>
</select>
</td>
</tr>
<tr>
<td>手机</td>
<td>
<input type="text" name="phone"/>
</td>
</tr>
<tr>
<td>邮箱</td>
<td>
<input type="text" name="email"/>
</td>
</tr>
<tr>
<td> </td>
<td>

<input type="submit" value="搜索"/>
<input type="reset" value="重置"/>
</td>
</tr>

</table>
</form>

</body>
</html>


这下查询表单也写好了，我们来实现query方法，还是回到Servlet

public String query(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

Customer customer=CommonUtils.toBean(request.getParameterMap(),Customer.class);

//        System.out.println(getUrl(request));
customer=encoding(customer);

int pc=getPc(request);
int pr=10;

PageBean<Customer> pb=  customerService.query(customer,pc,pr);

pb.setUrl(getUrl(request));

request.setAttribute("pb",pb);
return "/list.jsp";

}


我们再来实现service里面的query方法：

public PageBean<Customer> query(Customer customer, int pc, int pr) {
return customerDao.query(customer, pc,pr);
}


然后就是Dao里的查询：根QueryAll差不多，只是做了where查询限定

public PageBean<Customer> query(Customer customer, int pc, int pr) {
try {
PageBean<Customer> pb = new PageBean<Customer>();
pb.setPc(pc);
pb.setPr(pr);

StringBuilder cntSql = new StringBuilder("select count(*) from t_customer ");
StringBuilder whereSql = new StringBuilder(" where 1=1 ");
List<Object> params = new ArrayList<Object>();

String name = customer.getName();

if (name != null && !name.trim().isEmpty()) {
whereSql.append("and name like ?");
params.add("%" + name + "%");
}

String gender = customer.getGender();
if (gender != null && !gender.trim().isEmpty()) {
whereSql.append("and gender=?");
params.add(gender);
}

String phone = customer.getPhone();
if (phone != null && !phone.trim().isEmpty()) {
whereSql.append("and phone like ?");
params.add("%" + phone + "%");
}

String email = customer.getEmail();
if (email != null && !email.trim().isEmpty()) {
whereSql.append("and email like ?");
params.add("%" + email + "%");
}
Number num = (Number) qr.query(cntSql.append(whereSql).toString(), new ScalarHandler<>(), params.toArray());

pb.setTr(num.intValue());

StringBuilder sql = new StringBuilder("select * from t_customer ");
StringBuilder lmitSql = new StringBuilder(" limit ?,?");

params.add((pc - 1) * pr);
params.add(pr);

List<Customer> beanList = qr.query(sql.append(whereSql).append(lmitSql).toString(), new BeanListHandler<>(Customer.class), params.toArray());
pb.setBeanList(beanList);

return pb;
} catch (SQLException e) {
throw new RuntimeException(e);
}
}


我们把查询结果放在list.jsp显示，显示页面我们前面写好了，那我们来运行一下；

很好，正确显示了。

接下来就是修改删除了。

修改删除入口我放在了列表页面，

c:url value=’/CustomerServlet?method=preEdit&id=${cstm.id}’

修改客户信息

public String preEdit(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String id = request.getParameter("id");
Customer customer = customerService.find(id);

request.setAttribute("customer", customer);

return "/edit.jsp";
}


我们先通过查询我们需要修改的客户id，通过数据库查询到客户信息，然后传到edit页面进行编辑。

CustomerServier.java

...
public Customer find(String id) {
return customerDao.find(id);
}
...


CustomerDao.java

...
public Customer find(String id) {
try {
String sql = "select * from t_customer where id=?";
return qr.query(sql, new BeanHandler<Customer>(Customer.class), id);
} catch (Exception e) {
throw new RuntimeException(e);
}
}
...


，我们来新建一个edit.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri ="http://java.sun.com/jsp/jstl/core"%>
<html>
<head>
<title>Title</title>
</head>
<body>
<h3 align="center">编辑客户</h3>
<form action="<c:url value='/CustomerServlet'/>" method="post" >
<input type="hidden" name="method" value="edit"/>
<input type="hidden" name="id" value="${customer.id}"/>
<table border="0" align="center" width="40%" style="margin-left: 100px">
<tr>
<td width="100px">客户名称</td>
<td width="40%">
<input type="text" name="name" value="${customer.name}"/>
</td>
<td align="left">
<label id="nameError" class="error"> </label>
</td>
</tr>
<tr>
<td>客户性别</td>
<td>
<input type="radio" name="gender" value="male" id="male" <c:if test="${customer.gender eq 'male'}"/>checked="checked"/>
<label for="male">男</label>
<input type="radio" name="gender" value="female" id="female" <c:if test="${customer.gender eq 'female'}"/> checked="checked"/>
<label for="female">女</label>
</td>
<td>
<label id="genderError"class="error"> </label>
</td>
</tr>
<tr>
<td>手机</td>
<td>
<input type="text" name="phone" id="phone" value="${customer.phone}"/>
</td>
<td>
<label id="phoneError"class="error"> </label>
</td>
</tr>
<tr>
<td>邮箱</td>
<td>
<input type="text" name="email" id="email" value="${customer.email}"/>
</td>
<td>
<label id="emailError"class="error"> </label>
</td>
</tr>
<tr>
<td>描述</td>
<td>
<textarea rows="5" cols="30" name="description">${customer.description}</textarea>
</td>
<td>
<label id="discriptionError"class="error"> </label>
</td>
</tr>
<tr>
<td></td>
<td>
<input type="submit" name="submit" value="编辑客户"/>
<input type="reset" name="reset"/>
</td>
</tr>
</table>
</form>

</body>
</html>


好了，我们点击提交的时候会把修改后的用户信息存进表单调教给servlet的edit方法，我们现在来实现edit方法：

...
public String edit(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

Customer customer = CommonUtils.toBean(request.getParameterMap(), Customer.class);

customerService.edit(customer);

request.setAttribute("msg", "恭喜，编辑客户成功");
return "/msg.jsp";
}
...


好了，到这里，修改操作我们也完成了，哈哈哈哈哈哈哈哈哈。那还剩下一个删除操作。

删除客户

删除客户调用了servlet的删除方法：

c:url value=’/CustomerServlet?method=delete&id=${cstm.id}’

我们现在来实现一下delete方法：

...
public String delete(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

String id = request.getParameter("id");

customerService.delete(id);

request.setAttribute("msg", "恭喜，删除客户成功");

return "/msg.jsp";
}
...


，还是和前面一样：

CustomerServier.java

...
public void delete(String id) {
customerDao.delete(id);
}
...


CustomerDao.java

...
public void delete(String id) {
try {
String sql = "delete from t_customer where id=?";
qr.update(sql, id);
} catch (Exception e) {
throw new RuntimeException(e);
}
}
...


好了，删除我们也做完了，这下大功告成，一个简单的客户管理系统就完成了。大家需要lib的点击这里：

点击这里：
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