JAVA : error on ExecuteUpdate

Question

请我想向数据库添加一个元素，但我仍然遇到此错误，我不知道错误到底在哪里，并且我确定 sql 查询和我的数据库

com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'Ahmed,Saleh,2001/12/25,Cité les jasmins N°55, Sfax 3020,Saleh.BenAhmed@gmail.c' at line 1
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
    at com.mysql.jdbc.Util.getInstance(Util.java:386)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1054)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4120)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4052)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2503)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2664)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2809)
    at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1811)
    at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1725)
    at utils.DBHelper.executeUpdate(DBHelper.java:78)
    at dao.EtudiantDAO.Ajout(EtudiantDAO.java:21)
    at dao.EtudiantDAO.main(EtudiantDAO.java:30)
Exception in thread "main" java.lang.NullPointerException
    at utils.DBHelper.closePreparedStatement(DBHelper.java:106)
    at utils.DBHelper.close(DBHelper.java:87)
    at dao.EtudiantDAO.Ajout(EtudiantDAO.java:22)
    at dao.EtudiantDAO.main(EtudiantDAO.java:30)

这些是我的类(class):DBHelper.java

package utils;

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


public class DBHelper {
    public static Connection conn=null;
    static Statement stmt;
    private static PreparedStatement pstmt;
    private ResultSet rs;
    private static String driver_class_name="com.mysql.jdbc.Driver";
    private static String url="jdbc:mysql://localhost/gestetudiant";
    private static String username="root";
    private static String password="";

    public DBHelper(){


    }

    public static Connection getConnection(){



        try{
            Class.forName(driver_class_name);
            conn= DriverManager.getConnection(url, username, password);
        }
        catch(SQLException e){
            e.printStackTrace();
        }
        catch(ClassNotFoundException e){
            e.printStackTrace();
        }
        return (Connection) conn;

    }


    public static PreparedStatement getPreparedStatement(String sql){
        try {
            pstmt= getConnection().prepareStatement(sql);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return pstmt;
    }

    public static java.sql.Statement getStatement(){
        try {
            /* Création de l'objet gérant les requêtes */
            stmt = conn.createStatement();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return stmt;
    }

    public ResultSet executeQuery(String sql){
        try {
            rs=getStatement().executeQuery(sql);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return rs;
    }

    public static void executeUpdate(String sql){
        try {
            getStatement().executeUpdate(sql);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }   
    }

    public static void close(){
        closeConnection();
        closePreparedStatement();
        closeStatement();

    }

    private static void closeStatement() {
        // TODO Auto-generated method stub
        try {
            stmt.close();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

    private static void closePreparedStatement() {
        // TODO Auto-generated method stub
        try {
            pstmt.close();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

    private static void closeConnection() {
        // TODO Auto-generated method stub
        try {
            conn.close();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

}

学生.java

package model;

import java.util.Date;

/**
 * @author jk
 *
 */
public class Etudiant {

    private String cin;
    private String nom;
    private String prenom;
    private String datenaissance;
    private String adresse;
    private String mail;
    private String tel;

    public Etudiant(String cin, String nom, String prenom, String string, String adresse, String mail,
            String tel) {
        super();
        this.cin = cin;
        this.nom = nom;
        this.prenom = prenom;
        this.datenaissance = string;
        this.adresse = adresse;
        this.mail = mail;
        this.tel = tel;
    }

    public Etudiant() {
        super();
        // TODO Auto-generated constructor stub
    }

    protected void finalize() throws Throwable   
    {
        super.finalize();  
    }

    public String getCin() {
        return cin;
    }

    public void setCin(String cin) {
        this.cin = cin;
    }

    public String getNom() {
        return nom;
    }

    public void setNom(String nom) {
        this.nom = nom;
    }

    public String getPrenom() {
        return prenom;
    }

    public void setPrenom(String prenom) {
        this.prenom = prenom;
    }

    public String getDatenaissance() {
        return datenaissance;
    }

    public void setDatenaissance(String datenaissance) {
        this.datenaissance = datenaissance;
    }

    public String getAdresse() {
        return adresse;
    }

    public void setAdresse(String adresse) {
        this.adresse = adresse;
    }

    public String getMail() {
        return mail;
    }

    public void setMail(String mail) {
        this.mail = mail;
    }

    public String getTel() {
        return tel;
    }

    public void setTel(String tel) {
        this.tel = tel;
    }




}

EtudiantDAO.java

package dao;

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


import model.Etudiant;
import utils.DBHelper;

public class EtudiantDAO {

    private static Connection conn;

    private static void Ajout(Etudiant pObjEtud)

    {
        conn=DBHelper.getConnection();
        DBHelper.executeUpdate("INSERT into etudiant(cin,nom,prenom,datenaissance,adresse,mail,tel) VALUES("+pObjEtud.getCin()+","+pObjEtud.getNom()+","+pObjEtud.getPrenom()+","+pObjEtud.getDatenaissance()+","+pObjEtud.getAdresse()+","+pObjEtud.getMail()+","+pObjEtud.getTel()+")");
        DBHelper.close();


    }

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Etudiant e=new Etudiant("0256341","Ben Ahmed","Saleh","2001/12/25","Cité les jasmins N°55, Sfax 3020","Saleh.BenAhmed@gmail.com","+216 55223344");
        Ajout(e);


    }



}

Answer 1

基于文本的字段需要用引号引起来。使用DBHelper的getPreparedStatement方法

PreparedStatement ps = 
    DBHelper.getPreparedStatement("INSERT into etudiant(cin,nom,prenom,datenaissance,adresse,mail,tel) VALUES(?,?,?,?,?,?,?)");
ps.setString(1, pObjEtud.getCin());
...
ps.executeUpdate();