一个jdbc连接mysql的小例子
创建数据库
指定数据库字符集和校对规则：
mysql> create database it315 default character set gb2312 collate gb2312_chinese_ci;
进入刚创建的数据库:
mysql> use it315;
Database changed
创建表:
mysql> create table student (id int primary key,name varchar(20),address varchar(20));
写一个属性文件: jdbc_mysql.properties,此文件存储一些连接相关的信息:
driver=com.mysql.jdbc.Driver
//驱动名称
url=jdbc:mysql://localhost:3306/it315
//指定URL
user=root
//用户名
password=
//密码
characterEncoding=gb2312
//指定字符编码
写java源文件: JdbcMySql.java
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.Properties;
public class JdbcMySql {
public static Properties getProperties() {
Properties props = new Properties();
InputStream is = null;
try {
is = JdbcMySql.class
.getResourceAsStream("/jdbc_mysql.properties");
props.load(is);
} catch (Exception ex) {
ex.printStackTrace();
return null;
} finally {
if (is != null)
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return props;
}
public static void main(String[] args) {
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
Properties props = getProperties();
if (props != null){
//读取出属性文件里面的内容
String driver = props.getProperty("driver");
String url = props.getProperty("url");
String user = props.getProperty("user");
String password = props.getProperty("password");
String characterEncoding = props.getProperty("characterEncoding");
try {
Class.forName(driver);//加载驱动
conn = DriverManager.getConnection(url + "?characterEncoding="
+ characterEncoding, user, password);//建立连接
stmt = conn.createStatement();
String sql = "insert into student values(1,'张三','湖南')";
stmt.executeUpdate(sql);//执行sql语句
sql = "select * from Student";
rs = stmt.executeQuery(sql);
while (rs.next()) {//从结果集中取出数据
System.out.print(rs.getInt(1) + "\t");
System.out.print(rs.getString(2) + "\t");
System.out.print(rs.getString(3) + "\n");
}
} catch (Exception e) {
e.printStackTrace();
} finally {//释放连接
try {
if (rs != null)
rs.close();
if (stmt != null)
stmt.close();
if (conn != null)
conn.close();
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
}
}
编译运行:
C:\ >javac JdbcMySql.java
C:\ >java JdbcMySql
1 张三湖南
进数据库查询刚刚插入的信息:
mysql> select * from student;
+----+------+---------+
| id | name | address |
+----+------+---------+
| 1| ???| ??
|
+----+------+---------+
我们看到中文变成了问号.别急!退出mysql
mysql> quit;
Bye
再进去:
C:\ >mysql -uroot --default-character-set=gb2312
查询:
mysql> use it315;
Database changed
mysql> select * from student;
+----+--------+---------+
| id | name
| address |
+----+--------+---------+
| 1|张三| 湖南|
+----+--------+---------+
OK!一切正常了….