JDBC连接MySQL
加载及注册JDBC驱动程序
Class.forName("com.mysql.jdbc.Driver");
Class.forName("com.mysql.jdbc.Driver").newInstance();
JDBC URL 定义驱动程序与数据源之间的连接
标准语法:
<protocol(主要通讯协议)>:<subprotocol(次要通讯协议,即驱动程序名称)>:<data source identifier(数据源)>
MySQL的JDBC URL格式:
jdbc:mysql//[hostname][:port]/[dbname][?param1=value1][¶m2=value2]….
示例:jdbc:mysql://localhost:3306/sample_db?user=root&password=your_password
常见参数:
user 用户名
password 密码
autoReconnect 联机失败,是否重新联机(true/false)
maxReconnect 尝试重新联机次数
initialTimeout 尝试重新联机间隔
maxRows 传回最大行数
useUnicode 是否使用Unicode字体编码(true/false)
characterEncoding 何种编码(GB2312/UTF-8/…)
relaxAutocommit 是否自动提交(true/false)
capitalizeTypeNames 数据定义的名称以大写表示
建立连接对象
String url="jdbc:mysql://localhost:3306/sample_db?user=root&password=your_password";
Connection con = DriverManager.getConnection(url);
建立SQL陈述式对象(Statement Object)
Statement stmt = con.createStatement();
执行SQL语句
executeQuery()
String query = "select * from test";
ResultSet rs=stmt.executeQuery(query);
结果集ResultSet
while(rs.next())
{rs.getString(1);rs.getInt(2);}
executeUpdate()
String upd="insert into test (id,name) values(1001,xuzhaori)";
int con=stmt.executeUpdate(upd);
execute()
示例:
try
{
}
catch(SQLException sqle)
{
}
finally
{
}
Java类型和SQL类型技术手册P421
PreparedStatement(预编语句)
PreparedStatement stmt = conn.prepareStatement("insert into test(id,name)values(?,?)");
stmt.setInt(1,id);
stmt.setString(2,name);
注:一旦设定语句的参数值后,就可以多次执行改语句,直到调用clearParameters()方法将他清除为止
CallableStatement(预储程序)技术手册P430
JDBC2.0使用
ResultSet对象中的光标上下自由移动
Statement stmt = con.createStatement (ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);
ResultSet rs=stmt.executeQuery("select * from test");
public Statement createStatement(int resultSetType,int resultSetConcuttency) throws SQLException
resultSetType
TYPE_FORWARD_ONLY 只能使用next()方法。
TYPE_SCROLL_SENSITIVE 可以上下移动,可以取得改变后的值。
TYPE_SCROLL_INSENSITIVE 可以上下移动。
resultSetConcuttency
CONCUR_READ_ONLY 只读
CONCUR_UPDATABLE ResultSet对象可以执行数据库的新增、修改、和移除
直接使用ResultSet对象执行更新数据
新增数据
Statement stmt=con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_PUDATABLE);
ResultSet uprs=stmt.executeQuery("select * from test");
uprs.moveToInsertRow();
uprs.updateInt(1,1001);
uprs.updateString(2,"许召日");
uprs.insertRow;
更新数据
Statement stmt=con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_PUDATABLE);
ResultSet uprs=stmt.executeQuery("select * from test");
uprs.last();
uprs.updateString("name","xuzhaori");
uprs.updateRow;
删除数据
Statement stmt=con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_PUDATABLE);
ResultSet uprs=stmt.executeQuery("select * from test");
uprs.absolute(4);
uprs.deleteRow();
批处理
con.setAutoCommit(false); 关闭自动认可模式
Statement stmt=con.createStatement();
int[] rows;
stmt.addBatch("insert into test values(1001,xuzhaori)");
stmt.addBatch("insert into test values(1002,xuyalin)");
rows=stmt.executeBatch();
con.commit(); 没有任何错误,执行批处理stmt.executeBatch();
JNDI-数据源(Data Source)与连接池(Connection Pool)
Tomcat的JDBC数据源设置 技术手册P439
连接池工具-Proxool Var 0.8.3 技术手册P446
设置web.xml
<?xml version="1.0" encoding="ISO-8859-1"?>
<!--<?xml version="1.0" encoding="GB2312"?>-->
<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
version="2.4">
….
<servlet>
<servlet-name>ServletConfigurator</servlet-name>
<servlet-class>org.logicalcobwebs.proxool.configuration.ServletConfigurator</servlet-class>
<init-param>
<param-name>propertyFile</param-name>
<param-value>WEB-INF/classes/Proxool.properties</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
后端统计端口添加下列
<servlet>
<servlet-name>Admin</servlet-name>
<servlet-class>org.logicalcobwebs.proxool.admin.servlet.AdminServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Admin</servlet-name>
<url-pattern>/Admin</url-pattern>
</servlet-mapping>
….
</web-app>
配置Proxool.properties
jdbc-0.proxool.alias=JSPBook
jdbc-0.proxool.driver-class=com.mysql.jdbc.Driver
jdbc-0.proxool.driver-url=jdbc:mysql://localhost:3306/sample_db?user=root&password=browser&useUnicode=true&characterEncoding=UTF-8
jdbc-0.proxool.maximum-connection-count=10
jdbc-0.proxool.prototype-count=4
jdbc-0.proxool.house-keeping-test-sql=select CURRENT_DATE
jdbc-0.proxool.verbose=true
jdbc-0.proxool.statistics=10s,1m,1d 后端统计接口添加此行
jdbc-0.proxool.statistics-log-level=DEBUG
使用Proxool连接池
Connectioncon = DriverManager.getConnection("proxool.JSPBook");
Statementstmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
String query = "SELECT * FROM employee";
ResultSetrs = stmt.executeQuery(query);