学步园

Spring + mvc，Mybatis整合 （含事务配置，分页功能）

环境

WIN8 , Eclipse (Juno) , Maven 3.0.4 , Tomcat 7

为了方便测试分页功能，前台使用了jquery的Jqgrid插件。

1.建立项目

1.使用Eclipse新建一个Maven Project，Archetype选择 maven-archetype-webapp。

2.新建的项目中默认只有一个source folder - src/main/resources ,添加另外三个source folder来完善Maven的标准目录结构。

2.配置依赖

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>jo.geun</groupId>
    <artifactId>sampleProj</artifactId>
    <packaging>war</packaging>
    <version>0.0.1-SNAPSHOT</version>
    <name>sampleProj Maven Webapp</name>
    <url>http://maven.apache.org</url>
    <properties>
        <spring.version>3.1.3.RELEASE</spring.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.1.1</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>1.1.1</version>
        </dependency>
        <dependency>
            <groupId>commons-dbcp</groupId>
            <artifactId>commons-dbcp</artifactId>
            <version>1.4</version>
        </dependency>
        <dependency>
            <groupId>com.oracle</groupId>
            <artifactId>ojdbc6</artifactId>
            <version>11.2.0.3.0</version>
        </dependency>
        <dependency>
            <groupId>cglib</groupId>
            <artifactId>cglib</artifactId>
            <version>2.2.2</version>
        </dependency>
        <dependency>
            <groupId>taglibs</groupId>
            <artifactId>standard</artifactId>
            <version>1.1.2</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>
        <dependency>
            <groupId>org.codehaus.jackson</groupId>
            <artifactId>jackson-core-asl</artifactId>
            <version>1.9.11</version>
        </dependency>
        <dependency>
            <groupId>org.codehaus.jackson</groupId>
            <artifactId>jackson-mapper-asl</artifactId>
            <version>1.9.11</version>
        </dependency>
    </dependencies>
    <build>
        <finalName>sampleProj</finalName>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>2.5.1</version>
                <configuration>
                    <source>1.6</source>
                    <target>1.6</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

 需注意的是，因为Oracle做了些license的限制，Maven Central不提供Oracle的JDBC Driver的下载。我们只能手动下载JAR包（你也可以在Oracle DB或Client的安装目录中找到它），再用install命令注册到本地仓库中。

E:\>mvn install:install-file -Dfile=E:\instantclient_11_2\ojdbc6.jar -DgroupId=com.oracle -DartifactId=ojdbc6 -Dversion=11.2.0.3.0 -Dpackaging=jar

3.web.xml的配置

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
    <display-name>Sample Web Application</display-name>
    <!-- The definition of the Root Spring Container shared by all Servlets 
        and Filters -->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/spring/root-context.xml</param-value>
    </context-param>
    <!-- Creates the Spring Container shared by all Servlets and Filters -->
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    <!-- Processes application requests -->
    <servlet>
        <servlet-name>appServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>/WEB-INF/spring/servlet-context.xml</param-value>
        </init-param>
        <load-on-startup>0</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>appServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

 这里简简单单的说明一下吧。。

<context-param/> 节点配置contextConfigLocation属性是为了让ContextLoaderListener找到Spring上下文的位置并加载它，如果不指定contextConfigLocation，ContextLoaderListener会到/WEB-INF/目录下找applicationContext.xml来加载。


<listener/>  节点上配了ContextLoaderListener。它实现了ServletContextListener接口，所以web server启动时ContextLoaderListener能读取到ServletContext，也就能通过<context-param/>指定的Spring上下文的路径来找到上下文并加载它。

当然，如果你不需要Spring来管理你的Bean，可以去掉上面两个节点。

 <servlet/>和<servlet-mapping/>两个节点其实也不用多说，就是告诉容器匹配<url-pattern/>的请求都让Spring的 DispatcherServlet（就是一个Servlet，继承自HttpServlet）来处理。而它会把请求分发给其他控制器。详见Spring reference 16章 。

在WEB-INF目录下创建一个叫Spring的文件夹，上面指定的Spring的两个配置文件会放到这个文件夹内。

4.配置Spring mvc

在web.xml的<servlet/>节点中我们指定了servlet-context.xml。这里可以配拦截器还有视图解析器等，也可以配multipartResolver来实现文件上传功能。

<?xml version="1.0" encoding="UTF-8"?>
<beans:beans xmlns="http://www.springframework.org/schema/mvc"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:beans="http://www.springframework.org/schema/beans"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd">

    <!-- DispatcherServlet Context: defines this servlet's request-processing 
        infrastructure -->

    <!-- Enables the Spring MVC @Controller programming model -->
    <annotation-driven />

    <!-- Handles HTTP GET requests for /resources/** by efficiently serving 
        up static resources in the ${webappRoot}/resources directory -->
    <resources mapping="/resources/**" location="/resources/" />

    <!-- Resolves views selected for rendering by @Controllers to .jsp resources 
        in the /WEB-INF/views directory -->
    <beans:bean
        class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <beans:property name="prefix" value="/WEB-INF/pages/" />
        <beans:property name="suffix" value=".jsp" />
    </beans:bean>

    <context:component-scan base-package="jo.geun.controller" />
</beans:beans>

 这儿需要注意的是<context:component-scan/>节点。看到很多人问起让Spring来管理事务时候，事务为什么会不起作用，其中也有在这儿犯错的。。

 通常我们会做分层开发，在这个小例子中也分了controller、service 、 dao 三层，由service层来管理事务。

 如果在这个servlet context里面把service层也给scan了，service Bean就会被提前实例化，Spring的事务就没法控制事务对象了。所以一定要让这个扫描器过滤掉service层的扫描。

上面因为package的结构简单，就直接指定了controller层，其实也可以换种方式来写

<context:component-scan base-package="com.geun">
        <context:exclude-filter type="annotation"
            expression="org.springframework.stereotype.Service" />
</context:component-scan>

用上面的方式会过滤掉所有带@Service注解的类，也可以用正则表达式或AspectJ类型的表达式，具体的参阅官方文档。

5.root-context.xml

这儿主要包含了数据源及事务的配置,还有dao、service层bean的定义。

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans 

http://www.springframework.org/schema/beans/spring-beans-3.0.xsd


http://www.springframework.org/schema/context


http://www.springframework.org/schema/context/spring-context-3.0.xsd


http://www.springframework.org/schema/tx

    http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">

    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
        destroy-method="close">
        <!-- Connection Info -->
        <property name="driverClassName" value="oracle.jdbc.driver.OracleDriver" />
        <property name="url" value="jdbc:oracle:thin:@*******:1521:**" />
        <property name="username" value="**" />
        <property name="password" value="**" />

        <!-- Connection Pooling DBCP -->
        <property name="initialSize" value="5" />
        <property name="maxActive" value="100" />
        <property name="maxIdle" value="30" />
        <property name="maxWait" value="1000" />
        <property name="poolPreparedStatements" value="true" />
        <property name="defaultAutoCommit" value="false" />
    </bean>
    
    <bean id="transactionManager"
        class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource" />
    </bean>
    
    <tx:annotation-driven transaction-manager="transactionManager" />

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="configLocation" value="WEB-INF/mybatis/mybatis-conf.xml" />
    </bean>
    
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="jo.geun.dao;" />
    </bean>

    <context:component-scan base-package="jo.geun.service" />

</beans>

MapperScannerConfigurer会寻找指定包下的Mapper并自动将它们注册到到MapperFactoryBean代理工厂，这个代理工厂可以让你的mapper interface直接注入到其他bean中，而你完全不需要实现这个接口。不嫌累，也可以一个一个的注册Mapper接口,如下。

<bean id="sampleMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
        <property name="mapperInterface" value="jo.geun.dao.SampleMapper" />
        <property name="sqlSessionFactory" ref="sqlSessionFactory" />
</bean>

 6.mybatis-conf.xml

WEB-INF目录下创建文件夹mybatis,来放置它。

 

<?xml version="1.0" encoding="UTF-8" ?>  
    <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"  
    "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <settings>
        <setting name="cacheEnabled" value="true" />
        <setting name="lazyLoadingEnabled" value="true" />
        <setting name="aggressiveLazyLoading" value="false" />
        <setting name="multipleResultSetsEnabled" value="true" />
        <setting name="useColumnLabel" value="true" />
        <setting name="autoMappingBehavior" value="FULL" />
        <setting name="defaultExecutorType" value="SIMPLE" />
        <setting name="defaultStatementTimeout" value="25000" />
    </settings>
    <plugins>
        <plugin interceptor="jo.geun.utility.PagePlugin">
            <property name="dialect" value="oracle" />
            <property name="pageSqlId" value=".*ListPage.*" />
        </plugin>
    </plugins>
</configuration>  

如果mapper interface和mapper xml取一样的文件名，放到同一个包下就不用另配<mappers/>节点来告诉映射文件的位置了。

ibatis更名为mybatis以后加入了plugin功能，可以用它拦截执行语句的调用并扩展核心功能（Executer,StatementHandler 等）。这里我们用它来实现分页功能。

在之前在src/main/java下建5个package，附图

7.通过Mybatis的plugin做分页功能

utility包下新建一个POJO类。

package jo.geun.utility;

import java.io.Serializable;

public class PageInfo implements Serializable {

    private static final long serialVersionUID = 587754556498974978L;

    private int showCount = 10;
    private int totalPage;
    private int totalResult;
    private int currentPage;
    private int currentResult;

    private String sortField;
    private String order;
    
    //omit getter/setter methods ....
    
}

反射辅助类

package jo.geun.utility;

import java.lang.reflect.Field;


public class ReflectHelper {
    public static Field getFieldByFieldName(Object obj, String fieldName) {  
        for (Class<?> superClass = obj.getClass(); superClass != Object.class; superClass = superClass  
                .getSuperclass()) {  
            try {  
                return superClass.getDeclaredField(fieldName);  
            } catch (NoSuchFieldException e) {  
            }  
        }  
        return null;  
    }  
  
    /** 
     * Obj fieldName의 속성값 가져오기.  
     * @param obj 
     * @param fieldName 
     * @return 
     * @throws SecurityException 
     * @throws NoSuchFieldException 
     * @throws IllegalArgumentException 
     * @throws IllegalAccessException 
     */  
    public static Object getValueByFieldName(Object obj, String fieldName)  
            throws SecurityException, NoSuchFieldException,  
            IllegalArgumentException, IllegalAccessException {  
        Field field = getFieldByFieldName(obj, fieldName);  
        Object value = null;  
        if(field!=null){  
            if (field.isAccessible()) {  
                value = field.get(obj);  
            } else {  
                field.setAccessible(true);  
                value = field.get(obj);  
                field.setAccessible(false);  
            }  
        }  
        return value;  
    }  
  
    /** 
     * obj fieldName의 속성값 설정.
     * @param obj 
     * @param fieldName 
     * @param value 
     * @throws SecurityException 
     * @throws NoSuchFieldException 
     * @throws IllegalArgumentException 
     * @throws IllegalAccessException 
     */  
    public static void setValueByFieldName(Object obj, String fieldName,  
            Object value) throws SecurityException, NoSuchFieldException,  
            IllegalArgumentException, IllegalAccessException {  
        Field field = obj.getClass().getDeclaredField(fieldName);  
        if (field.isAccessible()) {  
            field.set(obj, value);  
        } else {  
            field.setAccessible(true);  
            field.set(obj, value);  
            field.setAccessible(false);  
        }  
    }  

}

 

拦截器 ，通过拦截StatementHandler的prepare方法来实现分页

package jo.geun.utility;

import java.lang.reflect.Field;

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.List;

import java.util.Map;

import java.util.Properties;
import javax.xml.bind.PropertyException;
import org.apache.ibatis.builder.xml.dynamic.ForEachSqlNode;

import org.apache.ibatis.executor.ErrorContext;

import org.apache.ibatis.executor.ExecutorException;

import org.apache.ibatis.executor.statement.BaseStatementHandler;

import org.apache.ibatis.executor.statement.RoutingStatementHandler;

import org.apache.ibatis.executor.statement.StatementHandler;

import org.apache.ibatis.mapping.BoundSql;

import org.apache.ibatis.mapping.MappedStatement;

import org.apache.ibatis.mapping.ParameterMapping;

import org.apache.ibatis.mapping.ParameterMode;

import org.apache.ibatis.plugin.Interceptor;

import org.apache.ibatis.plugin.Intercepts;

import org.apache.ibatis.plugin.Invocation;

import org.apache.ibatis.plugin.Plugin;

import org.apache.ibatis.plugin.Signature;

import org.apache.ibatis.reflection.MetaObject;

import org.apache.ibatis.reflection.property.PropertyTokenizer;

import org.apache.ibatis.session.Configuration;

import org.apache.ibatis.type.TypeHandler;

import org.apache.ibatis.type.TypeHandlerRegistry;
@Intercepts({ @Signature(type = StatementHandler.class, method = "prepare", args = { Connection.class }) })

public class PagePlugin implements Interceptor {
    private static String dialect = "";

    private static String pageSqlId = "";
    @SuppressWarnings("unchecked")

    public Object intercept(Invocation ivk) throws Throwable {
        if (ivk.getTarget() instanceof RoutingStatementHandler) {

            RoutingStatementHandler statementHandler = (RoutingStatementHandler) ivk

                    .getTarget();

            BaseStatementHandler delegate = (BaseStatementHandler) ReflectHelper

                    .getValueByFieldName(statementHandler, "delegate");

            MappedStatement mappedStatement = (MappedStatement) ReflectHelper

                    .getValueByFieldName(delegate, "mappedStatement");
            if (mappedStatement.getId().matches(pageSqlId)) {

                BoundSql boundSql = delegate.getBoundSql();

                Object parameterObject = boundSql.getParameterObject();

                if (parameterObject == null) {

                    throw new NullPointerException("parameterObject가 비여있음.");

                } else {

                    Connection connection = (Connection) ivk.getArgs()[0];

                    St