Java实现数据库与eclipse的连接

其他 2018-12-09 23:01:22 阅读次数: 0

JavaBean：用于传递数据，拥有与数据相关的逻辑处理

JSP：从Model接收数据并生成HTML

Servlet：接收HTTP请求并控制Model和View

jdbc：用于驱动连接

一、【建立数据库】

在mysql中新建一个名为course的数据库，并在其中新建一个course数据表，包含四个字段，ID，classname,classroom,teacher

二、【新建web项目】

1. eclipse新建一个名为course的Dynamic Web Project

修改class的默认输出目录为：WebContent/WEB-INF/classes,勾选自动生成web.xml

2. 将连接mysql的驱动jar包（

二、【新建web项目】

1. eclipse新建一个名为kechengguanlli的Dynamic Web Project

修改class的默认输出目录为：WebContent/WEB-INF/classes,勾选自动生成web.xml

2. 将连接mysql的驱动jar包（mysql-connector-java-5.1.7-bin.jar）copy到WEB-INF下的lib目录下

3.  新建7个包

4. 新建类，java类放在对应包中，jsp页面放在WebContent目录下，替换web.xml中内容

package com.hjf.dao;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

import com.hjf.entity.Course;
import com.hjf.util.DBUtil;

/**
 * 璇剧▼Dao
 * Dao灞傛搷浣滄暟鎹�
 * @author Hu
 *
 */
public class CourseDao {

    /**
     * 娣诲姞
     * @param course
     * @return
     */
    public boolean add(Course course) {
        String sql = "insert into course(name, teacher, classroom) values('" + course.getName() + "','" + course.getTeacher() + "','" + course.getClassroom() + "')";
        //鍒涘缓鏁版嵁搴撻摼鎺�
        Connection conn = DBUtil.getConn();
        Statement state = null;
        boolean f = false;
        int a = 0;
        
        try {
            state = conn.createStatement();
            state.executeUpdate(sql);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            //鍏抽棴杩炴帴
            DBUtil.close(state, conn);
        }
        
        if (a > 0) {
            f = true;
        }
        return f;
    }

    /**
     * 鍒犻櫎
     * 
     * @param id
     * @return
     */
    public boolean delete (int id) {
        boolean f = false;
        String sql = "delete from course where id='" + id + "'";
        
        Connection conn = DBUtil.getConn();
        Statement state = null;
        int a = 0;
        
        try {
            state = conn.createStatement();
            a = state.executeUpdate(sql);
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(state, conn);
        }
        
        if (a > 0) {
            f = true;
        }
        return f;
    }

    /**
     * 淇敼
     * @param name
     * @param pass
     */
    public boolean update(Course course) {
        String sql = "update course set name='" + course.getName() + "', teacher='" + course.getTeacher() + "', classroom='" + course.getClassroom()
            + "' where id='" + course.getId() + "'";
        Connection conn = DBUtil.getConn();
        Statement state = null;
        boolean f = false;
        int a = 0;

        try {
            state = conn.createStatement();
            a = state.executeUpdate(sql);
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(state, conn);
        }
        
        if (a > 0) {
            f = true;
        }
        return f;
    }
    
    /**
     * 楠岃瘉璇剧▼鍚嶇О鏄惁鍞竴
     * true --- 涓嶅敮涓�
     * @param name
     * @return
     */
    public boolean name(String name) {
        boolean flag = false;
        String sql = "select name from course where name = '" + name + "'";
        Connection conn = DBUtil.getConn();
        Statement state = null;
        ResultSet rs = null;
        
        try {
            state = conn.createStatement();
            rs = state.executeQuery(sql);
            while (rs.next()) {
                flag = true;
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(rs, state, conn);
        }
        return flag;
    }
    
    /**
     * 閫氳繃ID寰楀埌璇剧▼淇℃伅
     * @param id
     * @return
     */
    public Course getCourseById(int id) {
        String sql = "select * from course where id ='" + id + "'";
        Connection conn = DBUtil.getConn();
        Statement state = null;
        ResultSet rs = null;
        Course course = null;
        
        try {
            state = conn.createStatement();
            rs = state.executeQuery(sql);
            while (rs.next()) {
                String name = rs.getString("name");
                String teacher = rs.getString("teacher");
                String classroom = rs.getString("classroom");
                course = new Course(id, name, teacher, classroom);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(rs, state, conn);
        }
        
        return course;
    }
    
    /**
     * 閫氳繃name寰楀埌Course
     * @param name
     * @return
     */
    public Course getCourseByName(String name) {
        String sql = "select * from course where name ='" + name + "'";
        Connection conn = DBUtil.getConn();
        Statement state = null;
        ResultSet rs = null;
        Course course = null;
        
        try {
            state = conn.createStatement();
            rs = state.executeQuery(sql);
            while (rs.next()) {
                int id = rs.getInt("id");
                String teacher = rs.getString("teacher");
                String classroom = rs.getString("classroom");
                course = new Course(id, name, teacher, classroom);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(rs, state, conn);
        }
        
        return course;
    }
    
    /**
     * 鏌ユ壘
     * @param name
     * @param teacher
     * @param classroom
     * @return
     */
    public List<Course> search(String name, String teacher, String classroom) {
        String sql = "select * from course where ";
        if (name != "") {
            sql += "name like '%" + name + "%'";
        }
        if (teacher != "") {
            sql += "teacher like '%" + teacher + "%'";
        }
        if (classroom != "") {
            sql += "classroom like '%" + classroom + "%'";
        }
        List<Course> list = new ArrayList<>();
        Connection conn = DBUtil.getConn();
        Statement state = null;
        ResultSet rs = null;

        try {
            state = conn.createStatement();
            rs = state.executeQuery(sql);
            Course bean = null;
            while (rs.next()) {
                int id = rs.getInt("id");
                String name2 = rs.getString("name");
                String teacher2 = rs.getString("teacher");
                String classroom2 = rs.getString("classroom");
                bean = new Course(id, name2, teacher2, classroom2);
                list.add(bean);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(rs, state, conn);
        }
        
        return list;
    }
    
    /**
     * 鍏ㄩ儴鏁版嵁
     * @param name
     * @param teacher
     * @param classroom
     * @return
     */
    public List<Course> list() {
        String sql = "select * from course";
        List<Course> list = new ArrayList<>();
        Connection conn = DBUtil.getConn();
        Statement state = null;
        ResultSet rs = null;

        try {
            state = conn.createStatement();
            rs = state.executeQuery(sql);
            Course bean = null;
            while (rs.next()) {
                int id = rs.getInt("id");
                String name2 = rs.getString("name");
                String teacher2 = rs.getString("teacher");
                String classroom2 = rs.getString("classroom");
                bean = new Course(id, name2, teacher2, classroom2);
                list.add(bean);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(rs, state, conn);
        }
        
        return list;
    }

}
package com.hjf.entity;

public class Course {

    private int id;
    private String name;
    private String teacher;
    private String classroom;
    
    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 getTeacher() {
        return teacher;
    }
    public void setTeacher(String teacher) {
        this.teacher = teacher;
    }
    public String getClassroom() {
        return classroom;
    }
    public void setClassroom(String classroom) {
        this.classroom = classroom;
    }
    
    public Course() {}
    
    public Course(int id, String name, String teacher, String classroom) {
        this.id = id;
        this.name = name;
        this.teacher = teacher;
        this.classroom = classroom;
    }
    
    public Course(String name, String teacher, String classroom) {
        this.name = name;
        this.teacher = teacher;
        this.classroom = classroom;
    }
}
package com.hjf.service;

import java.util.List;

import com.hjf.dao.CourseDao;
import com.hjf.entity.Course;

/**
 * CourseService
 * 鏈嶅姟灞�
 * @author Hu
 *
 */
public class CourseService {

    CourseDao cDao = new CourseDao();
    
    /**
     * 娣诲姞
     * @param course
     * @return
     */
    public boolean add(Course course) {
        boolean f = false;
        if(!cDao.name(course.getName())) {
            cDao.add(course);
            f = true;
        }
        return f;
    }
    
    /**
     * 鍒犻櫎
     */
    public void del(int id) {
        cDao.delete(id);
    }
    
    /**
     * 淇敼
     * @return 
     */
    public void update(Course course) {
        cDao.update(course);
    }
    
    /**
     * 閫氳繃ID寰楀埌涓�涓狢ourse
     * @return 
     */
    public Course getCourseById(int id) {
        return cDao.getCourseById(id);
    }

    /**
     * 閫氳繃Name寰楀埌涓�涓狢ourse
     * @return 
     */
    public Course getCourseByName(String name) {
        return cDao.getCourseByName(name);
    }
    
    /**
     * 鏌ユ壘
     * @return 
     */
    public List<Course> search(String name, String teacher, String classroom) {
        return cDao.search(name, teacher, classroom);
    }
    
    /**
     * 鍏ㄩ儴鏁版嵁
     * @return 
     */
    public List<Course> list() {
        return cDao.list();
    }
}
package com.hjf.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.hjf.entity.Course;
import com.hjf.service.CourseService;

/**
 * Servlet implementation class CourseServlet
 */
@WebServlet("/CourseServlet")
public class CourseServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    CourseService service = new CourseService();
    /**
     * @see HttpServlet#HttpServlet()
     */
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");
        String method = req.getParameter("method");
        
        if ("add".equals(method)) {
            add(req, resp);
        } else if ("del".equals(method)) {
            del(req, resp);
        } else if ("update".equals(method)) {
            update(req, resp);
        } else if ("search".equals(method)) {
            search(req, resp);
        } else if ("getcoursebyid".equals(method)) {
            getCourseById(req, resp);
        } else if ("getcoursebyname".equals(method)) {
            getCourseByName(req, resp);
        } else if ("list".equals(method)) {
            list(req, resp);
        }
    }

    /**
     * 添加
     * @param req
     * @param resp
     * @throws IOException 
     * @throws ServletException 
     */
    private void add(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException {
        req.setCharacterEncoding("utf-8");
        //获取数据
        String name = req.getParameter("name");
        String teacher = req.getParameter("teacher");
        String classroom = req.getParameter("classroom");
        Course course = new Course(name, teacher, classroom);
        
        //添加后消息显示
        if(service.add(course)) {
            req.setAttribute("message", "添加成功");
            req.getRequestDispatcher("add.jsp").forward(req,resp);
        } else {
            req.setAttribute("message", "课程名称重复，请重新录入");
            req.getRequestDispatcher("add.jsp").forward(req,resp);
        }
    }
    
    /**
     * 全部
     * @param req
     * @param resp
     * @throws ServletException 
     */
    private void list(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
        req.setCharacterEncoding("utf-8");
        
        List<Course> courses = service.list();
        req.setAttribute("courses", courses);
        req.getRequestDispatcher("list.jsp").forward(req,resp);
    }

    /**
     * 通过ID得到Course
     * @param req
     * @param resp
     * @throws ServletException 
     */
    private void getCourseById(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
        req.setCharacterEncoding("utf-8");
        int id = Integer.parseInt(req.getParameter("id"));
        Course course = service.getCourseById(id);
        req.setAttribute("course", course);
        req.getRequestDispatcher("detail2.jsp").forward(req,resp);
    }

    /**
     * 通过名字查找
     * 跳转至删除
     * @param req
     * @param resp
     * @throws IOException
     * @throws ServletException 
     */
    private void getCourseByName(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
        req.setCharacterEncoding("utf-8");
        String name = req.getParameter("name");
        Course course = service.getCourseByName(name);
        if(course == null) {
            req.setAttribute("message", "查无此课程！");
            req.getRequestDispatcher("del.jsp").forward(req,resp);
        } else {
            req.setAttribute("course", course);
            req.getRequestDispatcher("detail.jsp").forward(req,resp);
        }
    }
    
    /**
     * 删除
     * @param req
     * @param resp
     * @throws IOException
     * @throws ServletException 
     */
    private void del(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
        req.setCharacterEncoding("utf-8");
        int id = Integer.parseInt(req.getParameter("id"));
        service.del(id);
        req.setAttribute("message", "删除成功！");
        req.getRequestDispatcher("del.jsp").forward(req,resp);
    }
    
    /**
     * 修改
     * @param req
     * @param resp
     * @throws IOException
     * @throws ServletException 
     */
    private void update(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
        req.setCharacterEncoding("utf-8");
        int id = Integer.parseInt(req.getParameter("id"));
        String name = req.getParameter("name");
        String teacher = req.getParameter("teacher");
        String classroom = req.getParameter("classroom");
        Course course = new Course(id, name, teacher, classroom);
        
        service.update(course);
        req.setAttribute("message", "修改成功");
        req.getRequestDispatcher("CourseServlet?method=list").forward(req,resp);
    }
    
    /**
     * 查找
     * @param req
     * @param resp
     * @throws ServletException 
     */
    private void search(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
        req.setCharacterEncoding("utf-8");
        String name = req.getParameter("name");
        String teacher = req.getParameter("teacher");
        String classroom = req.getParameter("classroom");
        List<Course> courses = service.search(name, teacher, classroom);
        req.setAttribute("courses", courses);
        req.getRequestDispatcher("searchlist.jsp").forward(req,resp);
    }
}
package com.hjf.util;

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

/**
 * 鏁版嵁搴撹繛鎺ュ伐鍏�
 * @author Hu
 *
 */
public class DBUtil {
    
    public static String db_url = "jdbc:mysql://localhost:3306/course?useUnicode=true&characterEncoding=utf8";
    public static String db_user = "root";
    public static String db_pass = "123456";
    
    public static Connection getConn () {
        Connection conn = null;
        
        try {
            Class.forName("com.mysql.jdbc.Driver");//鍔犺浇椹卞姩
            conn = DriverManager.getConnection(db_url, db_user, db_pass);
        } catch (Exception e) {
            e.printStackTrace();
        }
        
        return conn;
    }
    
    /**
     * 鍏抽棴杩炴帴
     * @param state
     * @param conn
     */
    public static void close (Statement state, Connection conn) {
        if (state != null) {
            try {
                state.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        
        if (conn != null) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
    
    public static void close (ResultSet rs, Statement state, Connection conn) {
        if (rs != null) {
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        
        if (state != null) {
            try {
                state.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        
        if (conn != null) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) throws SQLException {
        Connection conn = getConn();
        PreparedStatement pstmt = null;
        ResultSet rs = null;
        String sql ="select * from course";
        pstmt = conn.prepareStatement(sql);
        rs = pstmt.executeQuery();
        if(rs.next()){
            System.out.println("绌�");
        }else{
            System.out.println("涓嶇┖");
        }
    }
}

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