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876天前package mysql; |
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 TestConnection2 { |
private static Connection con = null; |
private static ResultSet result=null; |
private static PreparedStatement pre =null; |
public static void main(String[] args) { |
|
|
//1.加载数据库驱动 |
try { |
Class.forName("com.mysql.jdbc.Driver"); |
} catch (ClassNotFoundException e) { |
System.out.println("加载失败！"); |
e.printStackTrace(); |
} |
System.out.println("加载成功！"); |
|
//2.连接数据库 |
try { |
con=DriverManager.getConnection("jdbc:mysql://localhost:3306/db_library", "root", "123"); |
} catch (SQLException e) { |
System.out.println("连接数据库失败！"); |
e.printStackTrace(); |
} |
System.out.println("成功连接数据库！"); |
|
//3.处理数据库 |
try { |
/* pre = con.prepareStatement("create table teacher(id int not null auto_increment,name varchar(20) not null,age int not null,primary key(id))"); |
int result=pre.executeUpdate(); |
System.out.println(result); |
System.out.println("建表成功！");*/ |
|
/* |
* insert into table1(name, age) values('李四',22); |
*/ |
|
/*String name1="杨旋"; |
int age1=21; |
pre=con.prepareStatement("insert into teacher(name,age) values(?,?)"); |
pre.setString(1, name1); |
pre.setInt(2, age1); |
pre.executeUpdate(); |
System.out.println("添加成功！");*/ |
|
|
|
/* |
* update table1 set name='wanger',age=34 where id=1; |
*/ |
/*int id1=1; |
String name1="何欢"; |
int age1 =22; |
pre = con.prepareStatement("update teacher set name=?,age=? where id=?"); |
pre.setString(1, name1); |
pre.setInt(2, age1); |
pre.setInt(3, id1); |
int result = pre.executeUpdate(); |
System.out.println(result); |
System.out.println("修改成功！");*/ |
|
|
/* |
* delete from teacher where id=2 |
*/ |
/* int id1=2; |
pre=con.prepareStatement("delete from teacher where id=?"); |
pre.setInt(1, id1); |
pre.executeUpdate(); |
System.out.println("删除成功！");*/ |
|
/* |
* select * from teacher where id>3 |
*/ |
|
|
/*int id1=3; |
pre=con.prepareStatement("select * from teacher where id>?"); |
pre.setInt(1,id1); |
result =pre.executeQuery(); |
while(result.next()){ |
System.out.println(result.getInt("id")); |
System.out.println(result.getString("name")); |
System.out.println(result.getInt("age")); |
System.out.println("----------------------"); |
}*/ |
|
/* |
* select count(id) from teacher where id>3 |
*/ |
|
int id1=3; |
pre=con.prepareStatement("select count(id) from teacher where id>? "); |
pre.setInt(1, id1); |
result=pre.executeQuery(); |
if(result.next()){ |
int count = result.getInt(1); |
System.out.println(count); |
} |
|
} catch (SQLException e) { |
System.out.println("执行sql语句出错！"); |
e.printStackTrace(); |
return; |
} |
|
|
//4.释放数据库的资源 |
finally{ |
try { |
if(result!=null) |
result.close(); |
if(pre!=null) |
pre.close(); |
if(con!=null) |
con.close(); |
} catch (SQLException e) { |
e.printStackTrace(); |
} |
} |
System.out.println("执行成功！"); |
} |
} |
