JAVA连接数据库操作代码--干货

package cn.com.jdbc;

 

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

 

public class SQL {

 //1.占位符

 private static final String DRIVER="oracle.jdbc.driver.OracleDriver";

 private static final String URL="jdbc:oracle:thin:@localhost:1521:XE";

 private static final String root="system";

 private static final String pass="123";

 private static Connection conn=null;

 private static PreparedStatement ps=null;

 private static ResultSet rs=null;

 //1/封装链接数据库步骤

 public static Connection link(){

 try {

  Class.forName(DRIVER);

  conn=DriverManager.getConnection(URL,root,pass);

  

 } catch (ClassNotFoundException e) {

  // TODO Auto-generated catch block

  e.printStackTrace();

 } catch (SQLException e) {

  // TODO Auto-generated catch block

  e.printStackTrace();

 }

 return conn;

 }

 

 

 //关闭

 public static void closeAll(){

 if(rs!=null){

 try{

 rs.close();

 }catch(SQLException e){

 e.printStackTrace();

 }

 }

 if(ps!=null){

 try{

 ps.close();

 }catch(SQLException e){

 e.printStackTrace();

 }

 }

 if(conn!=null){

 try{

 conn.close();

 }catch(SQLException e){

 e.printStackTrace();

 }

 }

 

 }

 //1.查

 public static void select(String sql,String [] sz){

 try{

 conn=link();

 ps=conn.prepareStatement(sql);

 for(int i=0;i<sz.length;i++){

 ps.setString(i+1,sz[i]);

 }

 rs=ps.executeQuery();

 while(rs.next()){

 System.out.println(rs.getString("CLASSMATE"));

 }

 }catch(SQLException e){

 e.getStackTrace();

 }finally{

 closeAll();

 }

 }

 

 //2.增删改

 public static void update(String sql,String [] sz) {

 try{

 conn=link();

 ps=conn.prepareStatement(sql);

 for(int i=0;i<sz.length;i++){

 ps.setString(i+1,sz[i]);

 }

 ps.executeUpdate();

 }catch(SQLException e1){

 e1.printStackTrace();

 }finally{

 closeAll();

 }

 

 

 }

 public static void main(String [] tjn){

 String sql="update TJN set CLASSMATE=? where NAME=?";

 String sql1="insert into TJN(NAME,SEX,CLASSMATE) values(?,?,?)";

 String sql2="select SEX,CLASSMATE from TJN where NAME=?";

 String sql3="delete TJN where NAME=?";

 String sz []={"大内","海东来"};

 String sz1 []={"苏决","男","内卫"};

 String sz2 []={"夜沙罗"};

 String sz3 []={"恶猪王"};

  /*update(sql,sz);

   * update(sql1,sz1);

   * update(sql3,sz3);

   * */

 select(sql2,sz2);

 

 

 }

}