在servlet连接mysql下的最简单增删查改-白红宇

在servlet连接mysql下的最简单增删查改

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发布时间：2019-06-29

本文共 9827 字，大约阅读时间需要 32 分钟。

添加

package com.jquery.register;import java.io.IOException;import java.io.PrintWriter;import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class add extends HttpServlet {    public void destroy() {        super.destroy();     }    public void doGet(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {            doPost(request,response);    }    public void doPost(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        response.setContentType("text/html");        PrintWriter out = response.getWriter();        request.setCharacterEncoding("utf-8");          response.setCharacterEncoding("utf-8");         Connection conn = null;         PreparedStatement stmt = null;         ResultSet rs = null;         String name="li";         String password="12345";         String drive = "com.mysql.jdbc.Driver";         System.out.println("ajax后台交互成功");           try{             Class.forName(drive);             conn = DriverManager                     .getConnection("jdbc:mysql://localhost:3306/test?user=root&password=123");             System.out.println("数据库连接成功");             String sql="insert  into user_table(name,password)";             sql+=" values(?,?)";             stmt = conn.prepareStatement(sql);             stmt.setString(1,name);             stmt.setString(2,password);             stmt.executeUpdate();             System.out.println("success");//        out.flush();//        out.close();    }catch (ClassNotFoundException e) {            e.printStackTrace();        } catch (SQLException e) {            e.printStackTrace();        }finally {            try {                //注意关闭原则：从里到外                    if (rs != null) {                        rs.close();                    }                    if (stmt != null) {                        stmt.close();                    }                    if (conn != null) {                        conn.close();                    }                } catch (SQLException e) {                    e.printStackTrace();                }            }    }    public void init() throws ServletException {        // Put your code here    }}

删除

package com.jquery.register;import java.io.IOException;import java.io.PrintWriter;import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class delete extends HttpServlet {    public void destroy() {        super.destroy();    }    public void doGet(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {            doPost(request,response);    }    public void doPost(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        response.setContentType("text/html");        PrintWriter out = response.getWriter();        request.setCharacterEncoding("utf-8");         response.setCharacterEncoding("utf-8");         Connection conn = null;         PreparedStatement stmt = null;         ResultSet rs = null;         String drive = "com.mysql.jdbc.Driver";         System.out.println("ajax后台交互成功");           try{             Class.forName(drive);             conn = DriverManager                     .getConnection("jdbc:mysql://localhost:3306/test?user=root&password=123");             System.out.println("数据库连接成功");             String sql="delete  from user_table where name='zhang'";             stmt = conn.prepareStatement(sql);             stmt.executeUpdate();             System.out.println("success");//        out.flush();//        out.close();    }catch (ClassNotFoundException e) {            e.printStackTrace();        } catch (SQLException e) {            e.printStackTrace();        }finally {            try {                //注意关闭原则：从里到外                    if (rs != null) {                        rs.close();                    }                    if (stmt != null) {                        stmt.close();                    }                    if (conn != null) {                        conn.close();                    }                } catch (SQLException e) {                    e.printStackTrace();                }            }    }    public void init() throws ServletException {        // Put your code here    }}

查找

package com.jquery.register;import java.io.IOException;import java.io.PrintWriter;import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class search extends HttpServlet {    public void destroy() {        super.destroy();     }    public void doGet(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {            doPost(request,response);    }    public void doPost(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        response.setContentType("text/html");        PrintWriter out = response.getWriter();        request.setCharacterEncoding("utf-8");          response.setCharacterEncoding("utf-8");         Connection conn = null;         PreparedStatement stmt = null;         ResultSet rs = null;                  String drive = "com.mysql.jdbc.Driver";         System.out.println("ajax后台交互成功");           try{             Class.forName(drive);             conn = DriverManager                     .getConnection("jdbc:mysql://localhost:3306/test?user=root&password=123");             System.out.println("数据库连接成功");             String sql="select  *  from user_table ";                          stmt = conn.prepareStatement(sql);                          rs=stmt.executeQuery();                          System.out.println("success");             while(rs.next()){                 String name = rs.getString(1);                String password = rs.getString(2);                System.out.println(name + ", " + password);             }//        out.flush();//        out.close();    }catch (ClassNotFoundException e) {            e.printStackTrace();        } catch (SQLException e) {            e.printStackTrace();        }finally {            try {                //注意关闭原则：从里到外                    if (rs != null) {                        rs.close();                    }                    if (stmt != null) {                        stmt.close();                    }                    if (conn != null) {                        conn.close();                    }                } catch (SQLException e) {                    e.printStackTrace();                }            }    }    public void init() throws ServletException {        // Put your code here    }}

修改

package com.jquery.register;import java.io.IOException;import java.io.PrintWriter;import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class update extends HttpServlet {    public void destroy() {        super.destroy();     }    public void doGet(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {            doPost(request,response);    }    public void doPost(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        response.setContentType("text/html");        PrintWriter out = response.getWriter();        request.setCharacterEncoding("utf-8");          response.setCharacterEncoding("utf-8");         Connection conn = null;         PreparedStatement stmt = null;         ResultSet rs = null;         String password="654321";         String drive = "com.mysql.jdbc.Driver";         System.out.println("ajax后台交互成功");           try{             Class.forName(drive);             conn = DriverManager                     .getConnection("jdbc:mysql://localhost:3306/test?user=root&password=123");             System.out.println("数据库连接成功");             String sql="update user_table set password='"+password+"' where name='li'";                          stmt = conn.prepareStatement(sql);                          stmt.executeUpdate();                          System.out.println("success");             //        out.flush();//        out.close();    }catch (ClassNotFoundException e) {            e.printStackTrace();        } catch (SQLException e) {            e.printStackTrace();        }finally {            try {                //注意关闭原则：从里到外                    if (rs != null) {                        rs.close();                    }                    if (stmt != null) {                        stmt.close();                    }                    if (conn != null) {                        conn.close();                    }                } catch (SQLException e) {                    e.printStackTrace();                }            }    }    public void init() throws ServletException {        // Put your code here    }}