模糊查询与动态sql

1.导入Mybatis和Mysql相关jar包

2.建立数据库Mybatis并且建表User表，表里字段 id，name，age

3.mybatis配置文件 conf.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>      <!-- 对事务的管理和连接池的配置 -->      <!-- development :开发模式 -->      <!--  work：工作模式 -->    <environments default="development">          <environment id="development">              <transactionManager type="JDBC" />              <dataSource type="POOLED">                  <property name="driver" value="com.mysql.jdbc.Driver" />                  <property name="url" value="jdbc:mysql://localhost:3306/Mybatis" />                  <property name="username" value="root" />                  <property name="password" value="" />              </dataSource>          </environment>      </environments>      <!-- mapping 文件路径配置 -->     <mappers>         <!--  <mapper resource="com/zw/mybatis/studentsMapper.xml" />  -->       <!--  <mapper class="com.zw.mybatis.StudentsMapper" /> -->      <mapper resource="com/zw/mybatis/Mapper/UserMapper.xml" />     </mappers>  </configuration>

4.实体类User

package com.zw.mybatis.model;public class User { private int id; private String name; private int age; private int bumenid; private Bumen bumen; //关联表查询的关键 private Teacher teacher;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 int getBumenid() {return bumenid;}public void setBumenid(int bumenid) {this.bumenid = bumenid;}public User(int id, String name, int age, int bumenid) {super();this.id = id;this.name = name;this.age = age;this.bumenid = bumenid;}public User() {super();}public Bumen getBumen() {return bumen;}public void setBumen(Bumen bumen) {this.bumen = bumen;}public Teacher getTeacher() {return teacher;}public void setTeacher(Teacher teacher) {this.teacher = teacher;} }

5.查询条件实体类

package com.zw.mybatis.Condition;public class UserCondition {private String name;private int MinAge;private int MaxAge;public String getName() {return name;}public void setName(String name) {this.name = name;}public int getMinAge() {return MinAge;}public void setMinAge(int minAge) {MinAge = minAge;}public int getMaxAge() {return MaxAge;}public void setMaxAge(int maxAge) {MaxAge = maxAge;}public UserCondition(String name, int minAge, int maxAge) {super();this.name = name;MinAge = minAge;MaxAge = maxAge;}public UserCondition() {super();}}

6.UserMapper与UserMapper.xml

UserMapper

package com.zw.mybatis.model;public interface UserMapper {}

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.zw.mybatis.model.UserMapper"><!-- <select id="selectnameandteachnamebyid" parameterType="int" resultMap="newselectMap">select b.Teachername,a.name from User a,Teacher b where a.id=b.userid and a.id=#{0}</select><resultMap type="com.zw.mybatis.model.User" id="newselectMap"><result property="name" column="name" /><collection property="teacher" ofType="com.zw.mybatis.model.Teacher"><result property="Teachername" column="Teachername" /></collection></resultMap> --><select id="getuser" parameterType="com.zw.mybatis.Condition.UserCondition" resultType="com.zw.mybatis.model.User">select * from user where <if test='name != "%null%"'>name like #{name} and </if>age between #{MinAge} and #{MaxAge}</select></mapper>

7.测试类

package com.zw.mybatis.Test;import java.io.InputStream;import java.util.List;import org.apache.ibatis.session.SqlSession;import org.apache.ibatis.session.SqlSessionFactory;import org.apache.ibatis.session.SqlSessionFactoryBuilder;import com.zw.mybatis.Condition.UserCondition;import com.zw.mybatis.model.User;import com.zw.mybatis.model.UserMapper;public class UserTest {public static void main(String[] args) {String resourse = "conf.xml";InputStream is = UserTest.class.getClassLoader().getResourceAsStream(resourse);SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);SqlSession session = factory.openSession(true);UserCondition parameter=new UserCondition("%zhang%", 20, 25);List<User> list=session.selectList("com.zw.mybatis.model.UserMapper.getuser", parameter);System.out.println("姓名:"+list.get(0).getName());}}