JDBC连接数据库的步骤:
一、在开发环境中加载驱动:
我用的是Mysql,所以下载了mysql-connector-java-5.1.24-bin.jar。
在eclipse中建立新项目,在项目的buildpath中引入这个包。
二、在程序中加载驱动:
通过Class.forName("com.mysql.jdbc.Driver"); 来加载数据驱动程序。
三、建立数据库连接对象:
DriverManager.getConnection("jdbc:mysql://127.0.0.1/databasename", "username", "password");
这个方法得到一个数据连接对象。
四、Statement对象:
这个对象是用来执行sql语句的,假设前面我们得到的连接对象叫con。那么下面的方法可以读到一个Statement对象
con.createStatement();
五、接下来就可以执行sql语句了:
statement.execute(String yourSql);
statement有很多execute方式,根据不同需要来选择,会得到不同的反馈。
六、关闭连接:
con.close();
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Connection;
public class testJDBC {
static Connection conn = null;
static Statement stm = null;
public static void main(String[] args)
{
conn = connect();
show();
insert("LiuWeiZheng", 21, "woman");
delete("wanglu");
show();
}
public static void delete(String name)
{
String sql = "delete from mytable where name = \"" + name + "\";";
try {
stm = conn.createStatement();
int num = stm.executeUpdate(sql);
if(num != 0)
System.out.println("成功删除" + name);
} catch (SQLException e) {
System.out.println("删除失败");
}
}
public static void show()
{
String sql = "Select * from mytable order by age desc";
try {
stm = conn.createStatement();
ResultSet rs = stm.executeQuery(sql);
System.out.println("查询结果:");
while(rs.next())
{
String name = rs.getString("name");
int age = rs.getInt("age");
String sex = rs.getString("sex");
System.out.println("name: " + name + "---age: " + age + "---sex: " + sex);
}
} catch (SQLException e) {
e.printStackTrace();
}
}
public static void insert(String name ,int age, String sex)
{
String sql = "insert into mytable values(\"" + name + "\"," + age + ",\"" + sex + "\");";
try {
stm = conn.createStatement();
stm.execute(sql);
} catch (SQLException e) {
System.out.println("插入失败");
}
}
public static Connection connect()
{
Connection con = null;
try {
Class.forName("com.mysql.jdbc.Driver");
con = DriverManager.getConnection("jdbc:mysql://127.0.0.1/testjdbc", "root", "008421");
} catch (ClassNotFoundException e) {
System.out.println("加载驱动出错");
} catch (SQLException e) {
System.out.println("连接数据库出错");
}
return con;
}
}
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