数据源配制中有一些参数,不太明白,不明白的咱不说.在这说两种我用过的.
首先在apache-tomcat-6.0.16\lib 路径下的 mysql JDBC 5.1 驱动不能少.
第一种是在TomCat 里配制apache-tomcat-6.0.16\conf\context.xml 如下:
Xml代码
<?xml version='1.0' encoding='utf-8'?>
<Context>
<Resource name="jdbc/myTest" auth="Container"
type="javax.sql.DataSource" username="root" password=""
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://192.168.0.68:3306/points" />
<WatchedResource>WEB-INF/web.xml</WatchedResource>
</Context>
<?xml version='1.0' encoding='utf-8'?>
<Context>
<Resource name="jdbc/myTest" auth="Container"
type="javax.sql.DataSource" username="root" password=""
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://192.168.0.68:3306/points" />
<WatchedResource>WEB-INF/web.xml</WatchedResource>
</Context>
name 是数据源名称.格式是:"jdbc/数据源名称"
username,password 不用说了.这里password 密码为空.
url 和 JDBC 驱动配相同.
第二种是在项目里面配.WebRoot/META-INF/context.xml 中配:
Xml代码
<?xml version="1.0" encoding="UTF-8"?>
<Context>
<Resource name="jdbc/test" auth="Container"
type="javax.sql.DataSource" username="root" password=""
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://192.168.0.68:3306/points" />
</Context>
<?xml version="1.0" encoding="UTF-8"?>
<Context>
<Resource name="jdbc/test" auth="Container"
type="javax.sql.DataSource" username="root" password=""
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://192.168.0.68:3306/points" />
</Context>和在 Tomcat 里面几乎一样. context.xml 要注意是在 META-INF 下新建 是自己新建的.
数据源的使用:
Java代码
list = new ArrayList();
Connection conn = null;
DataSource ds = null;
PreparedStatement pst = null;
ResultSet rst = null;
String sqlStr = "insert into `user`(`userNo`,`userName`) values (?,?)";
try {
InitialContext ctx = new InitialContext();
ds = (DataSource) ctx.lookup("java:comp/env/jdbc/test");
conn = ds.getConnection();
pst = conn.prepareStatement(sqlStr);
pst.clearBatch();
for (int i = 0; i < 4; i++) {
pst.setString(1, "good " + i);
pst.setString(2, "isw " + i);
// 使用batch，将多个sql操作作为一个单元传输给数据库,
// Hibernate 中 jdbc.batch_size 网上推荐 30
pst.addBatch();
}
pst.executeBatch();
rst = pst.executeQuery("select * from user");
// Fetch Size 是设定JDBC的prepareStatement读取数据的时候每次从数据库中取出的记录条数,
// Hibernate 中 jdbc.fetch_size 网上推荐 50
rst.setFetchSize(50);
while (rst.next()) {
System.out.println(rst.getString(3));
list.add(rst.getString(3));
}
} catch (Exception e) {
e.printStackTrace();
return ERROR;
} finally {
try {
rst.close();
pst.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
list = new ArrayList();
Connection conn = null;
DataSource ds = null;
PreparedStatement pst = null;
ResultSet rst = null;
String sqlStr = "insert into `user`(`userNo`,`userName`) values (?,?)";
try {
InitialContext ctx = new InitialContext();
ds = (DataSource) ctx.lookup("java:comp/env/jdbc/test");
conn = ds.getConnection();
pst = conn.prepareStatement(sqlStr);
pst.clearBatch();
for (int i = 0; i < 4; i++) {
pst.setString(1, "good " + i);
pst.setString(2, "isw " + i);
// 使用batch，将多个sql操作作为一个单元传输给数据库,
// Hibernate 中 jdbc.batch_size 网上推荐 30
pst.addBatch();
}
pst.executeBatch();
rst = pst.executeQuery("select * from user");
// Fetch Size 是设定JDBC的prepareStatement读取数据的时候每次从数据库中取出的记录条数,
// Hibernate 中 jdbc.fetch_size 网上推荐 50
rst.setFetchSize(50);
while (rst.next()) {
System.out.println(rst.getString(3));
list.add(rst.getString(3));
}
} catch (Exception e) {
e.printStackTrace();
return ERROR;
} finally {
try {
rst.close();
pst.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
} 上面说一下,大家都说Hibernate 执行数据库操作要比手动JDBC 效率要高,这是因为它对查询进行了一些优化,Fetch Size,Batch 也许只是冰山一角.说到这里就提了一下它们的用法.
关于 Fectch Size,Batch 下面的博客给出较详细的说明.
http://xuganggogo.javaeye.com/blog/440516
数据源在Hibernate 中的使用 hibernate.cfg.xml
Xml代码
<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<!-- Generated by MyEclipse Hibernate Tools. -->
<hibernate-configuration>
<session-factory>
<!-- 下面是数据源的配制 -->
<property name="connection.datasource">
java:comp/env/jdbc/test
</property>
<!-- 数据库方言 -->
<property name="dialect">
org.hibernate.dialect.MySQLDialect
</property>
<property name="jdbc.batch_size">25</property>
<property name="jdbc.fetch_size">50</property>
<mapping resource="com/isw2/entity/UserBean.hbm.xml" />
</session-factory>
</hibernate-configuration>
<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<!-- Generated by MyEclipse Hibernate Tools. -->
<hibernate-configuration>
<session-factory>
<!-- 下面是数据源的配制 -->
<property name="connection.datasource">
java:comp/env/jdbc/test
</property>
<!-- 数据库方言 -->
<property name="dialect">
org.hibernate.dialect.MySQLDialect
</property>
<property name="jdbc.batch_size">25</property>
<property name="jdbc.fetch_size">50</property>
<mapping resource="com/isw2/entity/UserBean.hbm.xml" />
</session-factory>
</hibernate-configuration>
人生之所以的许许多多的半途而废及心有不甘,不过因为我们没有坚持自己的理想罢了,只要我们不放弃,理想终会实现.