mybatis与翰云库结合示例

这次主要是应客户要求，需要有多表查询结果返回，做的一个测试例子

建表语句：

CREATE TABLE  student  (   id int ,   name  varchar(10) NOT NULL,   gender  char(1) NOT NULL,   major  varchar(20) NOT NULL,   grade  char(4) NOT NULL,   supervisor_id  int NOT NULL) ;CREATE TABLE  teacher  (   id   int ,   name  varchar(10) NOT NULL,   gender  char(1) NOT NULL,   research_area  varchar(20) NOT NULL);INSERT INTO student VALUES (0, '李林', 'a', '计算机科学与技术', '2011', '1');INSERT INTO teacher VALUES (0,'张伟', 'a', '软件工程');

工程结构部署如下图：

Student.java

package mybatis;public class Student { private int id;   private String name;     // 姓名 private String gender;   // 性别 private String major;    // 专业 private String grade;    // 年级 private Teacher supervisor; //指导教师  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 String getGender() {  return gender; } public void setGender(String gender) {  this.gender = gender; } public String getMajor() {  return major; } public void setMajor(String major) {  this.major = major; } public String getGrade() {  return grade; } public void setGrade(String grade) {  this.grade = grade; } public Teacher getSupervisor() {  return supervisor; } public void setSupervisor(Teacher supervisor) {  this.supervisor = supervisor; }}

Teacher.java

package mybatis;import java.util.List;public class Teacher { private int id;     private String name;               // 教师姓名 private String gender;        // 教师性别 private String researchArea;    // 研究领域 private List<Student> supStudents; // 指导学生 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 String getGender() {  return gender; } public void setGender(String gender) {  this.gender = gender; } public String getResearchArea() {  return researchArea; } public void setResearchArea(String researchArea) {  this.researchArea = researchArea; } public List<Student> getSupStudents() {  return supStudents; } public void setSupStudents(List<Student> supStudents) {  this.supStudents = supStudents; }}

测试启动类：

package mybatis;import java.io.IOException;import java.io.Reader;import org.apache.ibatis.io.Resources;import org.apache.ibatis.session.SqlSession;import org.apache.ibatis.session.SqlSessionFactory;import org.apache.ibatis.session.SqlSessionFactoryBuilder;import org.omg.CORBA.portable.InputStream;public class Test1 {    public static void main(String[] args)  {        try {        //mybatis的配置文件        String resource = "conf.xml";        Reader reader = Resources.getResourceAsReader(resource);         //构建sqlSession的工厂        SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);        //创建能执行映射文件中sql的sqlSession        SqlSession session = sessionFactory.openSession();        String statement = "mybatis.StudentMapper.getById";//映射sql的标识字符串        Student s = session.selectOne(statement, 0);        System.out.println(s.getName()+s.getMajor()+" 1"+s.getSupervisor().getResearchArea());        } catch (Exception e) {            e.printStackTrace();            // TODO: handle exception        }    }}

配置文件：

<?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="mybatis.StudentMapper"> <!-- 定义java Bean的属性与数据库的列之间的映射 --> <resultMap type="mybatis.Student" id="studentResultMap">  <id column="id" property="id" />  <result column="st.name" property="name" />  <result column="st.gender" property="gender" />  <result column="st.major" property="major" />  <result column="st.grade" property="grade"/>   <association property="supervisor" javaType="mybatis.Teacher">   <id property="id" column="t_id"/>   <result property="name" column="t_name"/>   <result property="gender" column="t_gender"/>   <result property="researchArea" column="t_research_area"/>  </association> </resultMap> <!-- SQL语句中以"#{}"的形式引用参数  我是写死的 --> <select id="getById" parameterType="int" resultMap="studentResultMap">  SELECT st.id,st.name,st.gender,st.major,st.grade,t.id t_id,t.name t_name,   t.gender t_gender,t.research_area  t_research_area   FROM student st  inner join teacher t  on  st.id=t_id  WHERE   st.id=0  </select></mapper>

mybatis的链接配置文件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>     <environments default="development">         <environment id="development">             <transactionManager type="JDBC" />             <!-- 配置数据库连接信息 -->      <dataSource type="POOLED">                 <property name="driver" value="com.cloudwave.jdbc.CloudDriver" />                 <property name="url" value="jdbc:cloudwave:@localhost:1978" />                 <property name="username" value="itest" />                 <property name="password" value="itest" />             </dataSource>                  <!--   <dataSource type="POOLED">                 <property name="driver" value="oracle.jdbc.driver.OracleDriver" />                 <property name="url" value="jdbc:oracle:thin:@192.168.2.250:1521:orcl" />                 <property name="username" value="plsql" />                 <property name="password" value="plsql" />             </dataSource>-->         </environment>     </environments>     <mappers><!--      <mapper resource="mybatis/userMapper.xml"/>-->      <mapper resource="mybatis/StudentMapper.xml"/>  </mappers> </configuration>

因为不是直接返回一个map，需要把结果集处理下,所以这个调试花了点时间，也求助了同事，现在做点总结：

1. 的type和 的javaType需要把对应的路径写完整，要不然mybatis加载的时候会找不着该类
2. 的column有别名，写别名，没别名，就写表名+列名