db.properties 单独提取出来的数据库配置，方便以后维护管理
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mybatis
jdbc.username=root
jdbc.password=root
SqlMapConfig.xml
<?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>
<!-- 加载数据库连接参数配置文件 -->
<properties resource="db.properties" /> <!--
全局配置参数
比如 二级缓存 延迟加载...等
此全局参数会影响mybatis运行的性能，要谨慎配置
-->
<!-- <settings> -->
<!-- <setting name="" value=""/> -->
<!-- </settings> --> <!-- 定义别名 -->
<typeAliases>
<!-- 单个别名定义
type：pojo的路径
alias：别名的名称
-->
<!-- <typeAlias type="cn.itcast.mybatis.po.User" alias="user"/> -->
<!-- 批量别名定义
name：指定包名，将包下边的所有pojo定义别名 ，别名为类名（首字母大写或小写都行）
-->
<package name="com.mybatis.bean"/>
</typeAliases> <!-- 和spring整合后 environments配置将废除 -->
<environments default="development">
<environment id="development">
<transactionManager type="JDBC" />
<dataSource type="POOLED">
<property name="driver" value="${jdbc.driver}"/>
<property name="url" value="${jdbc.url}"/>
<property name="username" value="${jdbc.username}"/>
<property name="password" value="${jdbc.password}"/>
</dataSource>
</environment>
</environments> <!-- 配置mapper映射文件 -->
<mappers>
<!-- resource方式
在UserMapper.xml，定义namespace为mapper接口的地址，映射文件通过namespace找到对应的mapper接口文件
-->
<!-- <mapper resource="sqlmap/UserMapper.xml" /> -->
<!-- class方式
class：指定 mapper接口的地址
遵循规则：将mapper.xml和mapper.java文件放在一个目录 且文件名相同
-->
<!-- <mapper class="cn.itcast.mybatis.mapper.UserMapper"/> --> <!--
批量mapper扫描
遵循规则：将mapper.xml和mapper.java文件放在一个目录 且文件名相同
主要以这样的方式为主来加载mapper
-->
<package name="com.mybatis.mapper"/> </mappers>
</configuration>
UserMapper.java
package com.mybatis.mapper; import java.util.List;
import java.util.Map; import com.mybatis.bean.QueryVo;
import com.mybatis.bean.User; public interface UserMapper { public User findUserById(int id) throws Exception; public List<User> findUserList(String name) throws Exception; public Integer insertUser(User user) throws Exception; public void deleteUser(int id) throws Exception; public void updateUser(User user) throws Exception; public List<User> findUserByBean(User user) throws Exception; public List<User> findUserByMap(Map<String, Object> map) throws Exception; public List<User> findUserByCustom(QueryVo queryVo) throws Exception; // public Map findUserMapByCustom(QueryVo queryVo) throws Exception; public void updateUserSet(User user) throws Exception; }
UserMapper.xml
<?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.mybatis.mapper.UserMapper" > <!--
sql 片段，可以供其他的sql一起使用
建议以单表抽取查询条件
-->
<sql id="query_for_user">
<if test=" user != null ">
<if test=" user.name != null and user.name != '' ">
and name like '%${user.name}%'
</if>
<if test=" user.sex != null and user.sex != '' ">
and sex = #{user.sex}
</if>
</if> <if test="ids != null">
<foreach collection="ids" separator="or" item="item" open="and (" close=")">
id = #{item}
</foreach>
</if>
</sql> <select id="findUserById" parameterType="int" resultType="com.mybatis.bean.User">
SELECT * FROM USER WHERE id = #{id}
</select> <!--
#{} 表示占位符，#{}可以使用value或者其他字符，可以防止sql注入，使用时无需考虑参数的类型
${} 表示sql拼接，把原始的内容不加修饰的放入sql中，${}只能使用value，不可以防止sql注入，必须考虑参数的类型
一般在没有特殊情况下使用#{}为主
有些情况必须使用${}，比如
动态拼接表名：select * from ${tablename}, 如果使用了#{}则会在传入的表名上加单引号 ''
动态拼接排序字段：select * from user order by ${username} 举个栗子：
查询日期的区别：
select * from user where birthday >= #{date}
select * from user where birthday >= to_date('${date}', 'yyyy-MM-dd')
--> <select id="findUserList" parameterType="java.lang.String" resultType="com.mybatis.bean.User" >
select * from user where name like '%${value}%'
</select> <insert id="insertUser" parameterType="com.mybatis.bean.User">
<selectKey keyProperty="id" order="AFTER" resultType="java.lang.Integer">
select LAST_INSERT_ID()
</selectKey>
insert into user(name,age,sex) values(#{name},#{age},#{sex})
</insert> <delete id="deleteUser" parameterType="int">
delete from user where id=#{id}
</delete> <update id="updateUser" parameterType="com.mybatis.bean.User">
update user set name=#{name},age=#{age},sex=#{sex} where id=#{id}
</update> <select id="findUserByBean" parameterType="User" resultType="User">
select * from user where name like '%${name}%' and sex = #{sex}
</select> <select id="findUserByMap" parameterType="hashmap" resultType="User">
select * from user where name like '%${name}%' and age >= #{age}
</select> <!--
parameterMap 已经过期不建议使用, 官方已经废除
resultMap 不建议使用，太复杂
-->
<select id="findUserByCustom" parameterType="QueryVo" resultType="User">
select * from user <!--
where标签自动将 where后的第一个and去掉，比where 1=1 and 要好很多
where name like '%${user.name}%' and sex = #{user.sex}
-->
<!-- <where> -->
<!-- <if test=" user != null "> -->
<!-- <if test=" user.name != null and user.name != '' "> -->
<!-- and name like '%${user.name}%' -->
<!-- </if> -->
<!-- <if test=" user.sex != null and user.sex != '' "> -->
<!-- and sex = #{user.sex} -->
<!-- </if> -->
<!-- </if> -->
<!-- </where> --> <where>
<include refid="query_for_user"></include>
</where> </select> <!--
不建议使用map作为返回值，因为在代码中需要对key进行硬编码
-->
<!-- <select id="findUserMapByCustom" parameterType="QueryVo" resultType="hashmap"> -->
<!-- select * from user where name like '%${user.name}%' and sex >= #{user.sex} -->
<!-- </select> --> <update id="updateUserSet" parameterType="User">
update user
<set>
<if test="name != null and name != '' ">
name = #{name},
</if>
<if test="age != null and age != '' and age != 0 ">
age = #{age},
</if>
<if test="sex != null and sex != '' ">
sex = #{sex},
</if>
</set>
where id = #{id};
</update> </mapper>
QueryVo.java
package com.mybatis.bean; import java.util.List; /**
* 查询的封装类
*
* @author leechenxiang
* @date 2016年3月5日
*
*/
public class QueryVo { private User user; private UserCustom uc; private List<Integer> ids; public UserCustom getUc() {
return uc;
} public void setUc(UserCustom uc) {
this.uc = uc;
} public User getUser() {
return user;
} public void setUser(User user) {
this.user = user;
} public List<Integer> getIds() {
return ids;
} public void setIds(List<Integer> ids) {
this.ids = ids;
} }
User.java
package com.mybatis.bean;
public class User {
private int id;
private String name;
private int age;
private String sex;
public User() {
super();
}
public User(String name, int age, String sex) {
super();
this.name = name;
this.age = age;
this.sex = sex;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
@Override
public String toString() {
return "User [id=" + id + ", name=" + name + ", age=" + age + ", sex="
+ sex + "]";
}
}
UserCustom.java
package com.mybatis.bean; /**
* 扩展User的自定义类
* 扩展对象以'XxxxCustom'的格式命名
*
* @author leechenxiang
* @date 2016年3月5日
*
*/
public class UserCustom extends User { private String youngOrOld; public String getYoungOrOld() {
return youngOrOld;
} public void setYoungOrOld(String youngOrOld) {
this.youngOrOld = youngOrOld;
} }
最后附上github地址：https://github.com/leechenxiang/mybatis002-dynamic-proxy