java与数据库

java和数据库的连接，我们得先下一个包是专门用来与数据库连接的驱动还有方法，这边我们将此方法封装，然后这边的思路：加载驱动，进行连接（connection），创建向数据库发送命令的对象.

public static Connection getconnection() {// 加载驱动 且进行连接Connection connection=null;try {Class.forName("com.mysql.jdbc.Driver");String url="jdbc:mysql://localhost:3306/person?useSSL=false";connection=(Connection) DriverManager.getConnection(url, "root", "[e-mail]");} catch (ClassNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}return connection;}public static PreparedStatement getPreparedStatement(Connection con,String sql) {//设置发送sql 的方法PreparedStatement pre=null;try {pre=(PreparedStatement) con.prepareStatement(sql);} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}return pre ;}

package shuju;import java.sql.ResultSet;import java.sql.SQLException;import java.util.ArrayList;import java.util.HashMap;import java.util.Iterator;import java.util.List;import java.util.Map;import java.util.Map.Entry;import java.util.Set;import java.lang.reflect.*;import com.mysql.jdbc.Connection;import com.mysql.jdbc.Field;import com.mysql.jdbc.PreparedStatement;import com.mysql.jdbc.ResultSetMetaData;/** * 将数据库的内容以键值对的关系存入集合里 */public class Jdbc22 {public static void main(String[] args) {Connection con=Study_1.getconnection();String sql="select * from student";PreparedStatement p=Study_1.getPreparedStatement(con, sql);try {ResultSet re=p.executeQuery();//执行sql语句 并返回resultset对象ResultSetMetaData rest=(ResultSetMetaData) re.getMetaData();//获得结果集里的列的信息int count=rest.getColumnCount();//得到列的个数Map<String, Object> map=new HashMap();//map 集合List< Map<String, Object>> list= new ArrayList<>();//list集合/* * 先把结果存到map中 */while(re.next()) {// 会有个光标对象然后进行遍历for(int i=1;i<count;i++) {String name=rest.getColumnName(i);// 得到当前字段的名字Object value=re.getObject(name);//得到当前字段下对应的值map.put(name, value);//将值放入map中}list.add(map);// 将map放入集合中} Iterator it=list.iterator();//创建迭代器的对象while(it.hasNext()) {//list里全是map 对象所以不能直接遍历出来Map<String, Object> ma=(Map<String, Object>) it.next();//得到list里的mapSet<Map.Entry<String, Object>> set=(Set<Entry<String, Object>>) ma.entrySet();//set里是entry对象Iterator i=set.iterator();while(i.hasNext()) {Entry a=(Entry)i.next();System.out.println(a.getKey()+"    value:  "+a.getValue());}}} catch (SQLException e) { // TODO Auto-generated catch blocke.printStackTrace();}finally {Study_1.close(p, con);}}}

import java.sql.SQLException;import java.util.Set;import com.mysql.jdbc.Connection;import com.mysql.jdbc.PreparedStatement;import com.mysql.jdbc.Statement;public class Jdbc1 {public static void main(String[] args) {inyo();yyp();}public static void inyo() {Connection con=Study_1.getconnection();Long time=System.currentTimeMillis();String sql="insert into teacher (Tid,tname) values(?,?)";PreparedStatement sta=null;try {sta=(PreparedStatement) con.prepareStatement(sql);sta.setInt(1, 903);sta.setString(2, "王五");sta.addBatch();//将一组参数添加到PreparedStatement 中sta.setInt(1, 904);sta.setString(2, "王老无");sta.addBatch();sta.setInt(1, 902);sta.setString(2, "王老期");sta.addBatch();int [] a=sta.executeBatch();//执行一组参数若大于0则执行成功Long time1=System.currentTimeMillis();System.out.println(time1-time);} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}finally {try {sta.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}Study_1.close(sta, con);}}public static void yyp() {Connection con=Study_1.getconnection();Long time=System.currentTimeMillis();String sql="insert into teacher (Tid,tname) values(906,'网1')";String sql1="insert into teacher (Tid,tname) values(908,'网2')";String sql2="insert into teacher (Tid,tname) values(909,'网3')";String sql3="insert into teacher (Tid,tname) values(910,'网4')";System.out.println(sql);try {Statement sta=(Statement) con.createStatement();sta.addBatch(sql);sta.addBatch(sql2);sta.addBatch(sql1);sta.addBatch(sql3);int[] a=sta.executeBatch();Long time1=System.currentTimeMillis();System.out.println(time1-time);for(int b: a) {System.out.println(b);}} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}}

import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Types;import java.util.ArrayList;import java.util.HashMap;import java.util.Iterator;import java.util.List;import java.util.Map;import java.util.Map.Entry;import java.util.Set;import java.lang.reflect.*;import com.mysql.jdbc.CallableStatement;import com.mysql.jdbc.Connection;import com.mysql.jdbc.Field;import com.mysql.jdbc.PreparedStatement;import com.mysql.jdbc.ResultSetMetaData;//调用无参的存储过程public class Jdbc22 {public static void main(String[] args) {Connection con=Study_1.getconnection();/*String sql="call tt()";//无参的存储过程CallableStatement call=null;try {call = (CallableStatement) con.prepareCall(sql);ResultSet set=call.executeQuery();while(set.next()) {System.out.println(set.getString(1));}} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}finally{try {call.close();con.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}}*///调用in的有参数存储过程/*String sql="call tt1(?)";CallableStatement call=null;try {call=(CallableStatement) con.prepareCall(sql);call.setInt(1,555 );ResultSet rs=call.executeQuery();while(rs.next()) {System.out.println("5555");}} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}finally {try {call.close();con.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}}*///out 参数的存储过程/*String sql="call tt2(?)";CallableStatement call=null;try {call=(CallableStatement) con.prepareCall(sql);call.registerOutParameter(1,Types.INTEGER);call.executeQuery();int a = call.getInt(1);//接受返回的值} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}finally {try {call.close();con.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}}*///inout 存入存储过程String sql="call tt3(?)";try {CallableStatement call=(CallableStatement) con.prepareCall(sql);call.setInt(1, 233);call.registerOutParameter(1, Types.INTEGER);//按顺序位置 parameterIndex 将 OUT 参数注册为 JDBC 类型 sqlType。ResultSet re=call.executeQuery();//执行SQl 语句int a=call.getInt(1);} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}

上诉代码是一些基本的用法，仅供参考。