p6spy使用小结

     在之前的hibernate的总结中,遇到一个小问题,那就是打印sql语句的问题.在上个hibernate项目的基础上(spring+hibernate),继续p6spy的学习(p6spy相关文件下载)

hibernate控制sql语句的参数配置:

<!--开发调试使用 -->
<!--控制台打印sql语句 -->
<prop key="hibernate.show_sql">false</prop>
<!--格式化语句 -->
<prop key="hibernate.format_sql">false</prop>
<!--如果开启, Hibernate将在SQL中生成有助于调试的注释信息, 默认值为false -->
<prop key="hibernate.use_sql_comments">false</prop>

      但是这样有个问题,那就是hibernate中打印的参数都是一些?,实际上hibernate打印都是一些预编译的sql,无法打印真正的sql.回顾一些jdbc(java使用连接数据的api,Java DataBase Connectivity)直连数据库

Connection conn = null;
try {
// 第一步，注册驱动程序 以mysql驱动为例
Class.forName("com.mysql.jdbc.Driver");
// 第二步，获取一个数据库的连接
conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "123");
conn.setAutoCommit(false);

// 第三步，创建一个会话
//Statement stmt = conn.createStatement();
String sql = "select * from school s where s.id=?";
PreparedStatement stmt = conn.prepareStatement(sql);
stmt.setInt(1, 1);

// 第四步，执行SQL语句，增加，删除，修改记录 或者查询记录
// stmt.executeUpdate();
ResultSet rs = stmt.executeQuery();
ResultSetMetaData m = rs.getMetaData();

// 第五步，对查询的结果进行处理
int columns = m.getColumnCount();
// 显示列,表格的表头
for (int i = 1; i <= columns; i++) {
System.out.print(m.getColumnName(i));
System.out.print("\t\t");
}
System.out.println();
// 显示表格内容
while (rs.next()) {
for (int i = 1; i <= columns; i++) {
System.out.print(rs.getString(i));
System.out.print("\t\t");
}
System.out.println();
}
// 第六步，关闭连接
conn.commit();
rs.close();
stmt.close();
} catch (Exception e) {
e.printStackTrace();
System.out.println("进行回滚操作");
conn.rollback();
} finally {
conn.close();
}

       而我们通常配置的数据库驱动实现了与数据库的交互的前提,数据库连接池如druid,dbcp,c3p0,jboss datasource,bonecp,proxool等则管理通数据具体操作的连接connection,
通过一个个connection完成对具体数据的操作.

      从上例中可知,使用connection进行操作时摒弃了statement,而使用PreparedStatement,statement采用硬编码,每次执行sql都会进行编译,效率低,同时还能带来sql注入等不安全因素,而PreparedStatement相当于动态sql,对于相同的sql只会编译一次,参数通过注入的方式,有效阻止的sql注入,因此,项目中大多时候选择的是PreparedStatement,但对于那些一次性操作的,比如批量插入,删除等,可以直接使用statement.

hibernate默认使用的PreparedStatement,其取格式的sql是预编译的sql(参数没有被完全注入进来),从而会有一系列的?,要显示思路一种就是改变取sql的时机,等参数全部注入完成再取(p6spy),一种就是利用log,将传入的参数打印出来(这样sql,与参数分离),显然后一种没有前一种方便(hibernate打印sql)

p6spy使用com.p6spy.engine.spy.P6SpyDriver作为数据库驱动,P6SpyDriver是对原生原生驱动(此处以com.mysql.jdbc.Driver为例)的封装,其对数据的操作还是调用原生驱动的方法,只是多了sql监控的功能.

paspy基本使用.

配置驱动

<!--设置数据库连接 -->
<property name="driverClass" value="com.p6spy.engine.spy.P6SpyDriver" />

数据库连接(多了一个p6spy):

db.jdbcUrl  = jdbc:p6spy:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&rewriteBatchedStatements=true

spy.propertie

#配置输出方式
#appender=com.p6spy.engine.spy.appender.Slf4JLogger
#appender=com.p6spy.engine.spy.appender.FileLogger
appender=com.p6spy.engine.spy.appender.StdoutLogger

#配置输出内容格式(此处自定义)
#默认 com.p6spy.engine.spy.appender.SingleLineFormat
logMessageFormat=spring.redis.test.util.MySingleLineFormat

#输出内容选择
#list of categories to exclude: error, info, batch, debug, statement,
#commit, rollback and result are valid values
#
4000
(default is info,debug,result,resultset,batch)
excludecategories=info,batch,debug,commit,rollback,result,resultset

此处为了测试方便,使用控制台打印,自定义输出格式,输出内容选择statement

自定义输出内容格式:

package spring.redis.test.util;

import org.hibernate.engine.jdbc.internal.BasicFormatterImpl;

import com.p6spy.engine.spy.appender.SingleLineFormat;

public class MySingleLineFormat extends SingleLineFormat {
private final static BasicFormatterImpl sqlformat = new BasicFormatterImpl();
/**
* Formats a log message for the logging module
*
* @param connectionId the id of the connection
* @param now          the current ime expressing in milliseconds
* @param elapsed      the time in milliseconds that the operation took to complete
* @param category     the category of the operation
* @param prepared     the SQL statement with all bind variables replaced with actual values
* @param sql          the sql statement executed
* @return the formatted log message
*/
@Override
public String formatMessage(final int connectionId, final String now, final long elapsed, final String category, final String prepared, final String sql) {
return "#token time:" + elapsed + "ms | category:" + category + " | connectionId: " + connectionId + "\n" + "预编译语句"+sqlformat.format(prepared) + "\nread sql" + sqlformat.format(sql)
}
}

这是使用了hibernate格式化类,BasicFormatterImpl,以上展示的参数都是可以展示,测试打印

//执行打印sql
hibernateTemplate.get(School.class, 1);
/*		#token time:3ms | category:statement | connectionId: 2
预编译语句
select
school0_.id as id1_1_0_,
school0_.create_time as create_t2_1_0_,
school0_.des as des3_1_0_,
school0_.name as name4_1_0_,
school0_.update_time as update_t5_1_0_
from
school school0_
where
school0_.id=?
read sql
select
school0_.id as id1_1_0_,
school0_.create_time as create_t2_1_0_,
school0_.des as des3_1_0_,
school0_.name as name4_1_0_,
school0_.update_time as update_t5_1_0_
from
school school0_
where
school0_.id=1*/