MySQL_（Java）使用JDBC向数据库中删除（delete）数据

　　MySQL_(Java)使⽤JDBC向数据库发起查询请求　　　　MySQL_(Java)使⽤JDBC向数据库中插⼊(insert)数据　　　　MySQL_(Java)使⽤JDBC向数据库中删除(delete)数据　　　　MySQL_(Java)使⽤JDBC向数据库中修改(update)数据　　

　　MySQL数据库中的数据，数据库名garysql，表名garytb，删除数据库id=2的数据

import java.sql.Connection;import java.sql.DriverManager;

import java.sql.PreparedStatement;import java.sql.ResultSet;

import java.sql.SQLException;import java.sql.Statement;public class JDBC01 {

public static void main(String[] args) throws SQLException { delete(2); }

public static void selectAll() throws SQLException { //注册驱动 使⽤驱动连接数据库 Connection con = null; Statement stmt = null; ResultSet rs = null; try {

//数据库的连接

con = JDBCUtils.getConnection();

//数据库的增删改查

stmt = con.createStatement(); //返回⼀个结果集

rs =stmt.executeQuery(\"select * from garytb\");

while(rs.next()) {

//System.out.println(rs.getString(1)+\

System.out.println(rs.getString(\"id\")+\ }

} catch (Exception e) {

// TODO Auto-generated catch block e.printStackTrace(); }finally {

JDBCUtils.close(rs, stmt, con); } }

//校验⽤户

public static boolean selectByUernamePassword(String username,String password) throws SQLException { Connection con=null; Statement stmt = null; ResultSet rs = null; try {

Class.forName(\"com.mysql.jdbc.Driver\");

String url =\"jdbc:mysql://localhost:3306/garysql?useUnicode=true&characterEncoding=UTF8&useSSL=false\"; con = DriverManager.getConnection(url,\"root\ stmt =con.createStatement();

String sql = \"select * from garytb where username = '\"+username+\"' and password = '\"+password+\"'\"; //System.out.println(sql); rs = stmt.executeQuery(sql);

if(rs.next()) { return true;

}else {

return false; }

} catch (Exception e) {

// TODO Auto-generated catch block e.printStackTrace(); }finally {

if(rs!=null) rs.close(); if(stmt!=null) stmt.close(); if(con!=null) con.close(); }

return false; }

public static boolean selectByUP2(String username,String password) throws SQLException{ Connection con=null; Statement stmt = null; ResultSet rs = null; try {

Class.forName(\"com.mysql.jdbc.Driver\");

String url =\"jdbc:mysql://localhost:3306/garysql?useUnicode=true&characterEncoding=UTF8&useSSL=false\"; con = DriverManager.getConnection(url,\"root\

String sql = \"select * from garytb where username = ? and password = ?\"; PreparedStatement pstmt = con.prepareStatement(sql); //添加参数

pstmt.setString(1, username); pstmt.setString(2, password); //进⾏查询

rs = pstmt.executeQuery();

if(rs.next()) { return true; }else {

return false; }

} catch (Exception e) {

// TODO Auto-generated catch block e.printStackTrace(); }finally {

if(rs!=null) rs.close(); if(stmt!=null) stmt.close(); if(con!=null) con.close(); }

return false; }

//pageNumber是页数，第⼏页，pageCount是每页显⽰多少个数据

public static void selectUserByPage(int pageNumber,int pageCount) throws SQLException { //注册驱动 使⽤驱动连接数据库 Connection con = null;

PreparedStatement stmt = null; ResultSet rs = null; try {

Class.forName(\"com.mysql.jdbc.Driver\");

//String url =\"jdbc:mysql://localhost:3306/garysql\"; //指定编码查询数据库

String url =\"jdbc:mysql://localhost:3306/garysql?useUnicode=true&characterEncoding=UTF8&useSSL=false\"; String user = \"root\";

String password = \"123456\"; //建⽴和数据库的连接

con = DriverManager.getConnection(url,user,password);

stmt = con.prepareStatement(\"select * from garytb limit ?,?\"); stmt.setInt(1, (pageNumber-1)*pageCount ); stmt.setInt(2, pageCount);

rs = stmt.executeQuery();

while(rs.next()) {

//System.out.println(rs.getString(1)+\

System.out.println(rs.getString(\"id\")+\

}

} catch (Exception e) {

// TODO Auto-generated catch block e.printStackTrace(); }finally {

if(rs!=null) rs.close(); if(stmt!=null) stmt.close(); if(con!=null) con.close(); } }

//crud: create read updata delete //插⼊语句

public static void insert(String username,String password) throws SQLException { //注册驱动 使⽤驱动连接数据库 Connection con = null;

PreparedStatement stmt = null; ResultSet rs = null; try {

con = JDBCUtils.getConnection();

String sql = \"insert into garytb(username,password) values(?,?)\"; stmt = con.prepareStatement(sql); stmt.setString(1, username); stmt.setString(2, password);

int result =stmt.executeUpdate();// 返回值代表收到影响的⾏数 System.out.println(\"插⼊成功\"+username); } catch (Exception e) {

// TODO Auto-generated catch block e.printStackTrace(); }finally {

JDBCUtils.close(rs, stmt, con); } }

public static void delete(int id) throws SQLException { //注册驱动 使⽤驱动连接数据库 Connection con = null;

PreparedStatement stmt = null; ResultSet rs = null; try {

con = JDBCUtils.getConnection();

String sql = \"delete from garytb where id = ?\"; stmt = con.prepareStatement(sql); stmt.setInt(1, id);

int result =stmt.executeUpdate();// 返回值代表收到影响的⾏数 if(result>0) {

System.out.println(\"删除成功\"); }else {

System.out.println(\"删除失败\"); }

} catch (Exception e) { e.printStackTrace(); } finally {

JDBCUtils.close(rs, stmt, con); } }}

JDBC01.java

　　根据id删除数据库中的数据表

public static void delete(int id) throws SQLException { //注册驱动 使⽤驱动连接数据库 Connection con = null;

PreparedStatement stmt = null; ResultSet rs = null; try {

con = JDBCUtils.getConnection();

String sql = \"delete from garytb where id = ?\"; stmt = con.prepareStatement(sql); stmt.setInt(1, id);

int result =stmt.executeUpdate();// 返回值代表收到影响的⾏数 if(result>0) {

System.out.println(\"删除成功\");

}else {

System.out.println(\"删除失败\"); }

} catch (Exception e) { e.printStackTrace(); } finally {

JDBCUtils.close(rs, stmt, con); } }