spring - 带有spring 3的mybatis无法正常工作

Question

我正在尝试使用 spring 3 配置 mybatis 我正在关注文章

http://www.raistudies.com/spring/integrating-mybatis-3-and-spring-frameworks-part-2/

我正在使用 mybatis 生成器来生成所有的映射器和模型类。使用 mybatis 生成器后，我得到了以下类(class)。

import java.util.Date;

public class User extends BaseModel {

/**
 * This field was generated by MyBatis Generator. This field corresponds to the database column users.id
 * @mbggenerated  Fri Aug 03 09:28:44 BST 2012
 */
private Integer id;
/**
 * This field was generated by MyBatis Generator. This field corresponds to the database column users.username
 * @mbggenerated  Fri Aug 03 09:28:44 BST 2012
 */
private String username;
/**
 * This field was generated by MyBatis Generator. This field corresponds to the database column users.email
 * @mbggenerated  Fri Aug 03 09:28:44 BST 2012
 */
private String email;
/**
 * This field was generated by MyBatis Generator. This field corresponds to the database column users.crypted_password
 * @mbggenerated  Fri Aug 03 09:28:44 BST 2012
 */
 to the database column users.first_name
 * @mbggenerated  Fri Aug 03 09:28:44 BST 2012
 */
private String firstName;
/**
 * This field was generated by MyBatis Generator. This field corresponds to the database column users.last_name
 * @mbggenerated  Fri Aug 03 09:28:44 BST 2012
 */
private String lastName;
// I renoved the getter setter to save space.
}

它还创建了一个 UserExample.java 。我不明白为什么要创建这个文件。我只是应付这门课的一部分。

 import java.util.ArrayList;
 import java.util.Date;
 import java.util.List;

  public class UserExample {
/**
 * This field was generated by MyBatis Generator. This field corresponds to the database table users
 * @mbggenerated  Fri Aug 03 09:28:44 BST 2012
 */
protected String orderByClause;
/**
 * This field was generated by MyBatis Generator. This field corresponds to the database table users
 * @mbggenerated  Fri Aug 03 09:28:44 BST 2012
 */
protected boolean distinct;
/**
 * This field was generated by MyBatis Generator. This field corresponds to the database table users
 * @mbggenerated  Fri Aug 03 09:28:44 BST 2012
 */
protected List<Criteria> oredCriteria;

/**
 * This method was generated by MyBatis Generator. This method corresponds to the database table users
 * @mbggenerated  Fri Aug 03 09:28:44 BST 2012
 */
public UserExample() {
    oredCriteria = new ArrayList<Criteria>();
}

/**
 * This method was generated by MyBatis Generator. This method corresponds to the database table users
 * @mbggenerated  Fri Aug 03 09:28:44 BST 2012
 */
public void setOrderByClause(String orderByClause) {
    this.orderByClause = orderByClause;
}

/**
 * This method was generated by MyBatis Generator. This method corresponds to the database table users
 * @mbggenerated  Fri Aug 03 09:28:44 BST 2012
 */
public String getOrderByClause() {
    return orderByClause;
}

然后它创建 userMapper.xml 文件。我也没有处理整个文件以节省空间。

<?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.mycom.myproject.db.mybatis.dao.UserMapper">
<resultMap id="BaseResultMap" type="com.mycom.myproject.db.mybatis.model.User">
<!--
  WARNING - @mbggenerated
  This element is automatically generated by MyBatis Generator, do not modify.
  This element was generated on Fri Aug 03 09:28:44 BST 2012.
-->
<result column="id" jdbcType="INTEGER" property="id" />
<result column="username" jdbcType="VARCHAR" property="username" />
<result column="email" jdbcType="VARCHAR" property="email" />    
<result column="first_name" jdbcType="VARCHAR" property="firstName" />
<result column="last_name" jdbcType="VARCHAR" property="lastName" />
</resultMap>
 <sql id="Example_Where_Clause">
  <!--
  WARNING - @mbggenerated
  This element is automatically generated by MyBatis Generator, do not modify.
  This element was generated on Fri Aug 03 09:28:44 BST 2012.
-->
  <where>
  <foreach collection="oredCriteria" item="criteria" separator="or">
    <if test="criteria.valid">
      <trim prefix="(" prefixOverrides="and" suffix=")">
        <foreach collection="criteria.criteria" item="criterion">
          <choose>
            <when test="criterion.noValue">
              and ${criterion.condition}
            </when>
            <when test="criterion.singleValue">
              and ${criterion.condition} #{criterion.value}
            </when>
            <when test="criterion.betweenValue">
              and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
            </when>
            <when test="criterion.listValue">
              and ${criterion.condition}
              <foreach close=")" collection="criterion.value" item="listItem" open="(" separator=",">
                #{listItem}
              </foreach>
            </when>
          </choose>
        </foreach>
      </trim>
    </if>
  </foreach>
</where>
  </sql>
  <sql id="Update_By_Example_Where_Clause">
  <!--
  WARNING - @mbggenerated
  This element is automatically generated by MyBatis Generator, do not modify.
  This element was generated on Fri Aug 03 09:28:44 BST 2012.
-->
<where>
  <foreach collection="example.oredCriteria" item="criteria" separator="or">
    <if test="criteria.valid">
      <trim prefix="(" prefixOverrides="and" suffix=")">
        <foreach collection="criteria.criteria" item="criterion">
          <choose>
            <when test="criterion.noValue">
              and ${criterion.condition}
            </when>
            <when test="criterion.singleValue">
              and ${criterion.condition} #{criterion.value}
            </when>
            <when test="criterion.betweenValue">
              and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
            </when>
            <when test="criterion.listValue">
              and ${criterion.condition}
              <foreach close=")" collection="criterion.value" item="listItem" open="(" separator=",">
                #{listItem}
              </foreach>
            </when>
          </choose>
        </foreach>
      </trim>
    </if>
  </foreach>
 </where>
  </sql>
  <sql id="Base_Column_List">
  <!--
  WARNING - @mbggenerated
  This element is automatically generated by MyBatis Generator, do not modify.
  This element was generated on Fri Aug 03 09:28:44 BST 2012.
  -->
  id, username, email, crypted_password, password_salt, persistence_token, login_count, 
  failed_login_count, last_request_at, current_login_at, last_login_at,  current_login_ip, 
  last_login_ip, created_at, updated_at, creator_id, updater_id, first_name, last_name
 </sql>
  <select id="selectByExample"    parameterType="com.mycom.myproject.db.mybatis.model.UserExample" resultMap="BaseResultMap">
<!--
  WARNING - @mbggenerated
  This element is automatically generated by MyBatis Generator, do not modify.
  This element was generated on Fri Aug 03 09:28:44 BST 2012.
-->
  select
  <if test="distinct">
  distinct
  </if>
  <include refid="Base_Column_List" />
  from users
  <if test="_parameter != null">
  <include refid="Example_Where_Clause" />
  </if>
  <if test="orderByClause != null">
  order by ${orderByClause}
</if>

它还创建了我认为可以用于注入(inject)的 UserMapper 接口(interface)

import com.mycom.myproject.db.mybatis.model.User;
import com.mycom.myproject.db.mybatis.model.UserExample;
import java.util.List;
import org.apache.ibatis.annotations.Param;

public interface UserMapper {

/**
 * This method was generated by MyBatis Generator. This method corresponds to the database table users
 * @mbggenerated  Fri Aug 03 09:28:44 BST 2012
 */
int countByExample(UserExample example);

/**
 * This method was generated by MyBatis Generator. This method corresponds to the database table users
 * @mbggenerated  Fri Aug 03 09:28:44 BST 2012
 */
int deleteByExample(UserExample example);

/**
 * This method was generated by MyBatis Generator. This method corresponds to the database table users
 * @mbggenerated  Fri Aug 03 09:28:44 BST 2012
 */
int insert(User record);

/**
 * This method was generated by MyBatis Generator. This method corresponds to the database table users
 * @mbggenerated  Fri Aug 03 09:28:44 BST 2012
 */
int insertSelective(User record);

/**
 * This method was generated by MyBatis Generator. This method corresponds to the database table users
 * @mbggenerated  Fri Aug 03 09:28:44 BST 2012
 */
List<User> selectByExample(UserExample example);

/**
 * This method was generated by MyBatis Generator. This method corresponds to the database table users
 * @mbggenerated  Fri Aug 03 09:28:44 BST 2012
 */
int updateByExampleSelective(@Param("record") User record,
        @Param("example") UserExample example);

/**
 * This method was generated by MyBatis Generator. This method corresponds to the database table users
 * @mbggenerated  Fri Aug 03 09:28:44 BST 2012
 */
int updateByExample(@Param("record") User record,
        @Param("example") UserExample example);
}

我的 spring-servlet.xml 文件是

 <?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:p="http://www.springframework.org/schema/p"
  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-3.1.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.1.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd">


<!-- Enable annotation driven controllers, validation etc... -->
<mvc:annotation-driven />


<context:component-scan
base-package="com.mycom.myproject" />

<mvc:resources mapping="/resources/**" location="/resources/" />


<bean id="datasource" class="org.apache.commons.dbcp.BasicDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost/mydatabase"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
</bean>

 <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
    <property name="dataSource" ref="datasource" />
</bean>

<!-- scan for mappers and will automatically scan the whole classpath for xmls -->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
    <property name="sqlSessionFactory" ref="sqlSessionFactory" />
    <property name="basePackage" value="com.mycom.myproject.db.mybatis.dao" />
</bean>

<bean id="viewResolver"
class="org.springframework.web.servlet.view.UrlBasedViewResolver">
<property name="viewClass"
    value="org.springframework.web.servlet.view.JstlView" />
<property name="prefix" value="/WEB-INF/jsp/" />
<property name="suffix" value=".jsp" />
</bean>

现在我的问题是如何获取用户列表或简单的用户计数，如果我想的话。我在 mysql 数据库的用户表中有用户数。

我写了一个示例 Controller 类

@Controller
@RequestMapping("/")
public class LoginController
{
static final Logger logger = Logger.getLogger(LoginController.class);

private UserMapper userMapper =  null;



@RequestMapping("/login")
public ModelAndView login(@ModelAttribute User userBean, Model model){      

    return new ModelAndView("login", "userBean", userBean); 

}

@Autowired
public void setUserMapper(UserMapper userMapper) {
    this.userMapper = userMapper;
}

}

但它给了我以下错误。

 Error creating bean with name 'loginController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire method: public void com.mycom.myproject.controller.LoginController.setUserMapper(com.mycom.myproject.db.mybatis.dao.UserMapper); nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No matching bean of type [com.mycom.myproject.db.mybatis.dao.UserMapper] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}

Answer 1

在 userMapper.xml 中可以读取:

<mapper namespace="com.mycom.myproject.db.mybatis.dao.UserMapper">

但在你的 Spring 配置中

<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
    <property name="basePackage" value="com.mycom.mydatabase.db.mybatis.sqlmap" />
</bean>

我认为应该是

<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
    <property name="basePackage" value="com.mycom.myproject.db.mybatis.dao" />
</bean>