一个简单的servletJDBCweb项目
这个项目会用到webDom4j解析xml , 数据库 , junit ，3层架构
首先看一下这次项目的目录结构
下面依次贴出代码
首先bean
package com.my.servlet.bean;
import java.io.Serializable;
public class StudentBean implements Serializable{
private int id;
private String name;
private String sex;
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 String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
@Override
public String toString() {
return "StudentBean [id=" + id + ", name=" + name + ", sex=" + sex + "]";
}
}
工具类 主要使用dom4j解析xml连接数据库
xml文件
com.mysql.jdbc.Driver
jdbc:mysql://localhost:3306/test
root
123456
DBUtil类
package com.my.servlet.util;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
public class DBUtil {
// 加载驱动
static{
try {
Class.forName(dom4jDemo("driver"));
} catch (Exception e) {
// TODO: handle exception
}
}
/**
* 连接数据库
* @return 返回数据库连接
*/
public static Connection connectionSql(){
Connection conn = null;
try {
conn = DriverManager.getConnection(dom4jDemo("url"), dom4jDemo("user"), dom4jDemo("password"));
} catch (SQLException e) {
e.printStackTrace();
System.out.println("数据库连接错误 ");
}
return conn;
}
/**
* 解析xml 将数据保存在xml文件中 通过解析xml来获得
* @param element 需要得到的对象
* @return 返回这个对象在xml中的值
*/
public static String dom4jDemo(String element){
// 创建saxReader对象
SAXReader reader = new SAXReader();
// 通过read方法读取一个文件 转换成Document对象
Document document;
String result = "";
try { // 因为要使用web 所以使用ClassLoader来读取
ClassLoader classs = DBUtil.class.getClassLoader();
InputStream io = classs.getResourceAsStream("dbXml.xml");
document = reader.read(io);
//获取根节点元素对象
Element node = document.getRootElement();
result = node.element(element).getText();
} catch (DocumentException e) {
System.out.println("文件找不到");
e.printStackTrace();
}
return result;
}
}接口
package com.my.servlet.dao.idao;
import java.util.List;
import com.my.servlet.bean.StudentBean;
public interface IStudentDao {
/**
* 查询所有的学生
* @return
*/
public List getAllStudent();
} 实现类
package com.my.servlet.dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import com.my.servlet.bean.StudentBean;
import com.my.servlet.dao.idao.IStudentDao;
import com.my.servlet.util.DBUtil;
public class StudentBeanDao implements IStudentDao{
private DBUtil dbUtil = new DBUtil();
@Override
public List getAllStudent() {
Connection conn = dbUtil.connectionSql();
String sql = "SELECT t_student.sex,t_student.name,t_student.id FROM t_student";
List students = new ArrayList();
try {
// 使用预编译 防止注入
PreparedStatement prepatedStatement=conn.prepareStatement(sql);
ResultSet rs = prepatedStatement.executeQuery();
//循环结果集
while(rs.next()){
// 将值封装到对象中
StudentBean stu = new StudentBean();
stu.setId(rs.getInt("t_student.id"));
stu.setName(rs.getString("t_student.name"));
stu.setSex(rs.getString("t_student.sex"));
// 将对象添加到集合中
students.add(stu);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return students;
}
}
server(服务层)
package com.my.servlet.server.iserver;
import java.util.List;
import com.my.servlet.bean.StudentBean;
public interface IStudentServerDao {
/**
* 查询所有的学生
* @return
*/
public List getAllStudent();
} 实现
package com.my.servlet.server;
import java.util.List;
import com.my.servlet.bean.StudentBean;
import com.my.servlet.dao.StudentBeanDao;
import com.my.servlet.dao.idao.IStudentDao;
import com.my.servlet.server.iserver.IStudentServerDao;
public class StudentServer implements IStudentServerDao{
private IStudentDao isd = new StudentBeanDao();
@Override
public List getAllStudent() {
// TODO Auto-generated method stub
return isd.getAllStudent();
}
}
package com.my.servlet.servlet;
import java.io.IOException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.google.gson.Gson;
import com.my.servlet.bean.StudentBean;
import com.my.servlet.server.StudentServer;
import com.my.servlet.server.iserver.IStudentServerDao;
/**
* Servlet implementation class StudentServlet 因为版本3.0 所以采用的是注释
*/
@WebServlet("/StudentServlet")
public class StudentServlet extends HttpServlet {
private IStudentServerDao is = new StudentServer();
/**
* @see HttpServlet#HttpServlet()
*/
public StudentServlet() {
super();
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("====="); // 查询所有学生
List stus = is.getAllStudent(); // 使用Gson将值转换成json字符串 方便前台取值
Gson gson = new Gson(); // 将数据响应回界面
response.getWriter().print(gson.toJson(stus));
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
index.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
My JSP 'index.jsp' starting page
编号
名字
性别
最后是web.xml
Servlet
index.html
index.htm
index.jsp
default.html
default.htm
default.jsp
还有一个防止乱码的过滤器 （针对post）
如果是get的话需要采用字符串转码的格式
// 将gbk转化为utf-8
String a = "4";
String b = new String(a.getBytes("ISO8859-1"), "utf-8");过滤器
package com.my.servlet.filter;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
/**
* Servlet Filter implementation class EncodingFilter
*/
@WebFilter("/EncodingFilter")
public class EncodingFilter implements Filter {
/**
* Default constructor.
*/
public EncodingFilter() {
// TODO Auto-generated constructor stub
}
/**
* @see Filter#destroy()
*/
public void destroy() {
// TODO Auto-generated method stub
}
/**
* @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain)
*/
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
response.setCharacterEncoding("utf-8");
chain.doFilter(request, response);
}
/**
* @see Filter#init(FilterConfig)
*/
public void init(FilterConfig fConfig) throws ServletException {
// TODO Auto-generated method stub
}
}