Java DB 访问之(四) spring mvc 组合mybatis

说明

本项目采用 maven 结构，主要演示了 spring mvc + mybatis,controller 获取数据后以json 格式返回数据。

项目结构

包依赖 与说明

pom文件：

<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>com.hbb0b0.maven01</groupId>

<artifactId>maven01</artifactId>

<packaging>war</packaging>

<version>0.0.1-SNAPSHOT</version>

<name>maven01 Maven Webapp</name>

<url>http://maven.apache.org</url>

<properties>

<!-- mybatis版本号 -->

<mybatis.version>3.2.6</mybatis.version>

<!-- log4j日志文件管理包版本 -->

<slf4j.version>1.7.7</slf4j.version>

<log4j.version>1.2.17</log4j.version>

</properties>

<dependencies>

<dependency>

<groupId>junit</groupId>

<artifactId>junit</artifactId>

<version>3.8.1</version>

<scope>test</scope>

</dependency>

<dependency>

<groupId>org.springframework</groupId>

<artifactId>spring-webmvc</artifactId>

<version>4.1.2.RELEASE</version>

</dependency>

<!-- https://mvnrepository.com/artifact/org.codehaus.jackson/jackson-mapper-asl -->

<dependency>

<groupId>org.codehaus.jackson</groupId>

<artifactId>jackson-mapper-asl</artifactId>

<version>1.9.2</version>

</dependency>

<!-- https://mvnrepository.com/artifact/org.codehaus.jackson/jackson-core-asl -->

<dependency>

<groupId>org.codehaus.jackson</groupId>

<artifactId>jackson-core-asl</artifactId>

<version>1.9.13</version>

</dependency>

<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->

<dependency>

<groupId>com.fasterxml.jackson.core</groupId>

<artifactId>jackson-databind</artifactId>

<version>2.9.3</version>

</dependency>

<!-- mybatis/spring包 -->

<dependency>

<groupId>org.mybatis</groupId>

<artifactId>mybatis-spring</artifactId>

<version>1.3.0</version>

</dependency>

<!-- 导入Mysql数据库链接jar包 -->

<dependency>

<groupId>mysql</groupId>

<artifactId>mysql-connector-java</artifactId>

<version>5.1.30</version>

</dependency>

<!-- mybatis ORM框架 -->

<dependency>

<groupId>org.mybatis</groupId>

<artifactId>mybatis</artifactId>

<version>3.4.1</version>

</dependency>

<dependency>

<groupId>org.springframework</groupId>

<artifactId>spring-tx</artifactId>

<version>4.1.2.RELEASE</version>

</dependency>

<dependency>

<groupId>org.springframework</groupId>

<artifactId>spring-jdbc</artifactId>

<version>4.1.2.RELEASE</version>

</dependency>

</dependencies>

<build>

<finalName>maven01</finalName>

</build>

</project>

配置说明

• web.xml

<!DOCTYPE web-app PUBLIC
"-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
<display-name>Archetype Created Web Application</display-name>
<!--configure the setting of springmvcDispatcherServlet and configure the mapping-->
<servlet>
<servlet-name>springmvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/springmvc-servlet.xml</param-value>
</init-param>
<!-- <load-on-startup>1</load-on-startup> -->
</servlet>

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

• springmvc-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.1.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.1.xsd">

<!-- scan the package and the sub package -->
<context:component-scan base-package="com.maven01.*" />
<!-- don't handle the static resource -->
<mvc:default-servlet-handler />
<!-- if you use annotation you must configure following setting -->
<mvc:annotation-driven />
<!-- 对静态资源的处理 ，不需要dispatcher servelet -->
<mvc:resources mapping="/static/**" location="/static/" />
<!-- configure the InternalResourceViewResolver -->
<!-- if you use annotation you must configure following setting -->

<bean id="mappingJacksonHttpMessageConverter"
class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="supportedMediaTypes">
<list>
<value>application/json;charset=UTF-8</value>
</list>
</property>

</bean>
<bean
class="org.springframework.web.servlet.view.InternalResourceViewResolver"
id="internalResourceViewResolver">
<!-- 前缀 -->
<property name="prefix" value="/WEB-INF/view/" />
<!-- 后缀 -->
<property name="suffix" value=".jsp" />
</bean>
<!-- mysql -->
<!-- 引入外部数据源配置信息 -->
<bean
class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="locations">
<value>classpath:jdbc.properties</value>
</property>
</bean>

<!-- 配置数据源 -->
<bean id="dataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="${jdbc.driver}"></property>
<property name="url" value="${jdbc.url}"></property>
<property name="username" value="${jdbc.username}"></property>
<property name="password" value="${jdbc.password}"></property>
</bean>

<!-- spring和MyBatis完美整合，不需要mybatis的配置映射文件 -->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<!-- 自动扫描mapping.xml文件 -->
<property name="mapperLocations" value="classpath:com/maven01/mapper/*.xml"></property>

</bean>

<!-- DAO接口所在包名，Spring会自动查找其下的类 -->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="basePackage" value="com.maven01.dao" />
<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>
</bean>

<!-- 配置事务管理器 -->
<bean id="txManager"
class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource"></property>
</bean>

</beans>

• jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver

jdbc.url=jdbc:mysql://localhost:3306/employees?useUnicode=true&characterEncoding=UTF-8

jdbc.username=root

jdbc.password=sqlsa

• mybatis mapper 文件的配置

<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >

<mapper namespace="com.maven01.dao.IEmployeeDao">

<select id="getAll" resultType="com.maven01.pojo.Employee">

select

*

from

employees

limit 1,10

</select>

</mapper>

db结构

本项目采用了 mysql 的示例 employees 数据库, 需要的朋友可以自行下载 。

http://www3.ntu.edu.sg/home/ehchua/programming/sql/SampleDatabases.html

代码说明

• model

package com.maven01.pojo;

public class Employee {

public int emp_no;

public String first_name;

public int getEmp_no() {

return emp_no;

}

public void setEmp_no(int emp_no) {

this.emp_no = emp_no;

}

public String getFirst_name() {

return first_name;

}

public void setFirst_name(String first_name) {

this.first_name = first_name;

}

}

• dao

package com.maven01.dao;

import java.util.List;

import org.springframework.stereotype.Repository;

import com.maven01.pojo.Employee;

public interface IEmployeeDao {

public List<Employee> getAll();

}

• service

package com.maven01.service;

import java.util.List;

import com.maven01.pojo.Employee;

public interface IEmployeeService {

public List<Employee> getAll();

}

• serviceImpl

package com.maven01.service.impl;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Service;

import com.maven01.dao.IEmployeeDao;

import com.maven01.pojo.Employee;

import com.maven01.service.*;

import javax.annotation.Resource;

@Service

public class EmployeeServiceImpl implements IEmployeeService

{

@Autowired

private IEmployeeDao dao ;

public EmployeeServiceImpl()

{

}

public List<Employee> getAll() {

return dao.getAll();

}

}

• controller

package com.maven01.controller;

import java.util.ArrayList;

import java.util.List;

import javax.annotation.Resource;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestMethod;

import org.springframework.web.bind.annotation.ResponseBody;

import com.maven01.dto.*;

import com.maven01.pojo.Employee;

import com.maven01.service.IEmployeeService;

@Controller

@RequestMapping("/mvc")

public class DemoController {

@Resource

private IEmployeeService employeeService;

@RequestMapping(method = RequestMethod.GET, value = "/getEmployeeList", produces = "application/json")

public @ResponseBody List<Employee> getEmployeeList() {

return employeeService.getAll();

}

}

运行结果

本项目代码已提交 git ,下载地址 https://github.com/hbb0b0/springMyBatis.git

遇到的坑：

• MapperScannerConfigurer 配置为仅仅包含dao层就可以了，千万不要配置问整个包扫描，不然会出现错误：No qualifying bean of type [com.maven01.service.IEmployeeService] is defined: expected single matching bean but found 2: employeeServiceImpl,IEmployeeService

<!-- DAO接口所在包名，Spring会自动查找其下的类 -->

<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">

<property name="basePackage" value="com.maven01.*" />

<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>

</bean>

org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [com.maven01.service.IEmployeeService] is defined: expected single matching bean but found 2: employeeServiceImpl,IEmployeeService

at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1061)

<!-- DAO接口所在包名，Spring会自动查找其下的类 -->

<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">

<property name="basePackage" value="com.maven01.dao" />

<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>

</bean>

• 注意mybatis 包的匹配 较低版本 mybatis-spring 与 mybatis 与 spring 结合会出现

java.lang.AbstractMethodError: org.mybatis.spring.transaction.SpringManagedTransaction.getTimeout()L