目录
Java数据库连接，（Java Database Connectivity，简称JDBC）是java语言中用来规范客户端程序如何来访问数据库的应用程序接口，提供了诸如查询和更新数据库中数据的方法，我们通常说的JDBC是面向关系型数据库的。
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.29</version>
</dependency>注意：在使用JDBC之前要保证数据库远程连接服务启动！
1.Class.forName()加载驱动
2.DriverManager获取Connection连接
3.创建Statement执行SQL语句
4.增删改操作使用preparedStatement.executeUpdate();返回影响的行数
查询操作使用preparedStatement.executeQuery();返回查询结果
5.释放资源
首先创建表：
create table if not exists dog ( id int(10) primary key auto_increment, name varchar(32) comment '宠物名', health int(10) comment '健康值', love int(10) comment '亲密度', strain varchar(32) comment '品种', lytime datetime comment '领养时间' );
package jdbcstu;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
public class Dog {
public static void main(String[] args) {
Connection connection = null;
PreparedStatement preparedStatement = null;
try {
// com.mysql.jdbc.Driver
// 第一步：加载驱动
Class.forName("com.mysql.jdbc.Driver");
// 第二步：获取Connection对象
connection = DriverManager.getConnection(
"jdbc:mysql://192.168.180.141:3306/jdbcstudb", // mysql服务器地址，端口，数据库名
"root", // 数据库的用户名
"root" // 数据库密码
);
System.out.println(connection);
// 第三步：操作数据库 增删改查
/*新增*/
// String sql = "insert into dog(name,health,love,strain,lytime) values(?,?,?,?,?)";
String sql = "insert into dog(name,health,love,strain,lytime) values(?,?,?,?,now())";
String name = "ggg";
Integer health = 92;
Integer love = 66;
String strain = "斗牛";
// Date date = new Date(System.currentTimeMillis());// 只能存年月日
// 第三步：创建preparedstatement
preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1,name);
preparedStatement.setInt(2,health);
preparedStatement.setInt(3,love);
preparedStatement.setString(4,strain);
// preparedStatement.setDate(5,date);
// 第四步：获取到执行新增语句后的返回结果
int num = preparedStatement.executeUpdate(); // 返回影响的行数
if(num > 0){
System.out.println("新增宠物狗成功！");
}
}catch (ClassNotFoundException e){
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}finally {
// 第五步：释放资源
try {
if (preparedStatement != null) {
preparedStatement.close();
}
if (connection != null) {
connection.close();
}
}catch (SQLException e) {
e.printStackTrace();
}
}
}
}
package jdbcstu;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
public class Dog {
public static void main(String[] args) {
Connection connection = null;
PreparedStatement preparedStatement = null;
try {
// com.mysql.jdbc.Driver
// 第一步：加载驱动
Class.forName("com.mysql.jdbc.Driver");
// 第二步：获取Connection对象
connection = DriverManager.getConnection(
"jdbc:mysql://192.168.180.141:3306/jdbcstudb", // mysql服务器地址，端口，数据库名
"root", // 数据库的用户名
"root" // 数据库密码
);
System.out.println(connection);
// 第三步：操作数据库 增删改查
String sql = "delete from dog where name = ? and health = ?";
preparedStatement = connection.prepareStatement(sql);
String name = "ggg";
Integer health = 92;
preparedStatement.setString(1,name);
preparedStatement.setInt(2,health);
int num = preparedStatement.executeUpdate();
if(num>0){
System.out.println("删除成功！"+num);
}
}catch (ClassNotFoundException e){
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}finally {
// 第五步：释放资源
try {
if (preparedStatement != null) {
preparedStatement.close();
}
if (connection != null) {
connection.close();
}
}catch (SQLException e) {
e.printStackTrace();
}
}
}
}
package jdbcstu;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
public class Dog {
public static void main(String[] args) {
Connection connection = null;
PreparedStatement preparedStatement = null;
try {
// com.mysql.jdbc.Driver
// 第一步：加载驱动
Class.forName("com.mysql.jdbc.Driver");
// 第二步：获取Connection对象
connection = DriverManager.getConnection(
"jdbc:mysql://192.168.180.141:3306/jdbcstudb", // mysql服务器地址，端口，数据库名
"root", // 数据库的用户名
"root" // 数据库密码
);
System.out.println(connection);
// 第三步：操作数据库 增删改查
String sql = "update dog set name = ?,health = ?,love = ? where id = ?";
preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1,"二哈");
preparedStatement.setInt(2,99);
preparedStatement.setInt(3,80);
preparedStatement.setInt(4,2);
int num = preparedStatement.executeUpdate();
if(num > 0){
System.out.println("修改宠物狗成功！");
}
}catch (ClassNotFoundException e){
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}finally {
// 第五步：释放资源
try {
if (preparedStatement != null) {
preparedStatement.close();
}
if (connection != null) {
connection.close();
}
}catch (SQLException e) {
e.printStackTrace();
}
}
}
}
package jdbcstu;
import java.sql.*;
public class Dog {
public static void main(String[] args) {
Connection connection = null;
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;
try {
// com.mysql.jdbc.Driver
// 第一步：加载驱动
Class.forName("com.mysql.jdbc.Driver");
// 第二步：获取Connection对象
connection = DriverManager.getConnection(
"jdbc:mysql://192.168.180.141:3306/jdbcstudb", // mysql服务器地址，端口，数据库名
"root", // 数据库的用户名
"root" // 数据库密码
);
System.out.println(connection);
// 第三步：操作数据库 增删改查
String sql = "select id,name,health,love,strain,lytime from dog where health = ? and strain = ? limit ?,?";
preparedStatement = connection.prepareStatement(sql);
preparedStatement.setInt(1,99);
preparedStatement.setString(2,"哈士奇");
preparedStatement.setInt(3,0);
preparedStatement.setInt(4,2);
resultSet = preparedStatement.executeQuery();
System.out.println("\t\t\t狗狗信息");
System.out.println("编号\t宠物名\t健康值\t亲密度\t品种\t\t领养时间");
while (resultSet.next()){
System.out.print(resultSet.getInt("id")+"\t");
System.out.print(resultSet.getString("name")+"\t\t");
System.out.print(resultSet.getInt("health")+"\t\t");
System.out.print(resultSet.getInt("love")+"\t\t");
System.out.print(resultSet.getString("strain") + "\t\t");
System.out.println(resultSet.getDate("lytime")+"\t");
}
}catch (ClassNotFoundException e){
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}finally {
// 第五步：释放资源
try {
if (preparedStatement != null) {
preparedStatement.close();
}
if (connection != null) {
connection.close();
}
if(resultSet != null){
resultSet.close();
}
}catch (SQLException e) {
e.printStackTrace();
}
}
}
}
package jdbcstu;
import java.sql.*;
public class Master {
public static void main(String[] args) {
Connection connection = null;
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;
try {
// 第一步：加载驱动
Class.forName("com.mysql.jdbc.Driver");
// 第二步：获取connection对象
connection = DriverManager.getConnection(
"jdbc:mysql://192.168.180.141:3306/jdbcstudb",
"root",
"root"
);
System.out.println(connection);
// 第三步：操作数据库 增删改查
/*查询数据*/
String sql = "select m.name ,\n" +
" m.age ,\n" +
" m.gender ,\n" +
" m.yearnum ,\n" +
" d.name ,\n" +
" d.health ,\n" +
" d.love \n" +
" from master m\n" +
"join dog d on m.did = d.id\n" +
"where m.age > ?\n" +
"order by d.id desc\n" +
"limit ?";
preparedStatement = connection.prepareStatement(sql);
preparedStatement.setInt(1,30);
preparedStatement.setInt(2,2);
resultSet = preparedStatement.executeQuery();
System.out.println("\t\t\t领养信息");
System.out.println("主人姓名\t主人年龄\t主人性别\t主人经验值\t宠物名\t宠物健康值\t宠物亲密度");
while (resultSet.next()){
System.out.print(resultSet.getString("m.name")+"\t\t");
System.out.print(resultSet.getInt("m.age")+"\t\t");
System.out.print(resultSet.getString("m.gender")+"\t\t");
System.out.print(resultSet.getInt("m.yearnum") + "\t\t\t");
System.out.print(resultSet.getString("d.name")+"\t\t");
System.out.print(resultSet.getInt("d.health")+"\t\t\t");
System.out.println(resultSet.getInt("d.love")+"\t\t");
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}finally {
try {
if (connection != null) {
connection.close();
}
if(preparedStatement != null){
preparedStatement.close();
}
if(resultSet != null){
resultSet.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}