ibatis 入门

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iBatis 简介:

iBatis apache 的一个开源项目,一个O/R Mapping 解决方案,iBatis 最大的特点就是小巧,上手很快。如果不需要太多复杂的功能,iBatis 是能够满足你的要求又足够灵活的最简单的解决方案,现在的iBatis 已经改名为Mybatis 了。

官网为:http://www.mybatis.org/

搭建iBatis 开发环境:

1 、导入相关的jar 包,ibatis-2.3.0.677.jarmysql-connector-java-5.1.6-bin.jar

2 、编写配置文件:

  Jdbc 连接的属性文件  (eg:SqlMap.properties)

  总配置文件 (SqlMapConfig.xml)

  关于每个实体的映射文件(Map 文件) (eg:Student.xml)

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本文以 对学生Student的 增删改查为例

Demo:

工程目录:

数据库结构截图:


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1. Student.java

package com.ibatis.entity;import java.sql.Date;public class Student {// 注意这里需要保证有一个无参构造方法,因为包括Hibernate在内的映射都是使用反射的,如果没有无参构造可能会出现问题 private int id;private String name;private Date birth;private float score;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 Date getBirth() {return birth;}public void setBirth(Date birth) {this.birth = birth;}public float getScore() {return score;}public void setScore(float score) {this.score = score;}@Overridepublic String toString() {return "Student [id=" + id + ", name=" + name + ", birth=" + birth+ ", score=" + score + "]";}}

2. SqlMap.properties

driver=com.mysql.jdbc.Driverurl=jdbc:mysql://localhost:3306/mydbusername=rootpassword=123456

3. Student.xml

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE sqlMap PUBLIC "-//ibatis.apache.org//DTD SQL Map 2.0//EN"   "http://ibatis.apache.org/dtd/sql-map-2.dtd"><sqlMap><!-- 通过typeAlias使得我们在下面使用Student实体类的时候不需要写包名 --><typeAlias alias="Student" type="com.ibatis.entity.Student" /><!-- 这样以后改了sql,就不需要去改java代码了 --><!-- id表示select里的sql语句,resultClass表示返回结果的类型 --><select id="selectAllStudent" resultClass="Student">select * fromtbl_student</select><!-- parameterClass表示参数的内容 --><!-- #表示这是一个外部调用的需要传进的参数,可以理解为占位符 --><select id="selectStudentById" parameterClass="int" resultClass="Student">select * from tbl_student where id=#id#</select><!-- 注意这里的resultClass类型,使用Student类型取决于queryForList还是queryForObject --><select id="selectStudentByName" parameterClass="String"resultClass="Student">select name,birth,score from tbl_student where name like'%$name$%'</select><insert id="addStudent" parameterClass="Student">insert intotbl_student(name,birth,score) values(#name#,#birth#,#score#);<selectKey resultClass="int" keyProperty="id">select @@identity as inserted<!-- 这里需要说明一下不同的数据库主键的生成,对各自的数据库有不同的方式: --><!-- mysql:SELECT LAST_INSERT_ID() AS VALUE --><!-- mssql:select @@IDENTITY as value --><!-- oracle:SELECT STOCKIDSEQUENCE.NEXTVAL AS VALUE FROM DUAL --><!-- 还有一点需要注意的是不同的数据库生产商生成主键的方式不一样,有些是预先生成 (pre-generate)主键的,如Oracle和PostgreSQL。 有些是事后生成(post-generate)主键的,如MySQL和SQL Server 所以如果是Oracle数据库,则需要将selectKey写在insert之前 --></selectKey></insert><delete id="deleteStudentById" parameterClass="int"><!-- #id#里的id可以随意取,但是上面的insert则会有影响,因为上面的name会从Student里的属性里去查找 --><!-- 我们也可以这样理解,如果有#占位符,则ibatis会调用parameterClass里的属性去赋值 -->delete from tbl_student where id=#id#</delete><update id="updateStudent" parameterClass="Student">update tbl_student setname=#name#,birth=#birth#,score=#score# where id=#id#</update></sqlMap>

4. SqlMapConfig.xml

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE sqlMapConfig PUBLIC "-//ibatis.apache.org//DTD SQL Map Config 2.0//EN"    "http://ibatis.apache.org/dtd/sql-map-config-2.dtd"><sqlMapConfig><!-- 引用JDBC属性的配置文件 --><properties resource="com/ibatis/SqlMap.properties" /><!-- 使用JDBC的事务管理 --><transactionManager type="JDBC"><!-- 数据源 --><dataSource type="SIMPLE"><property name="JDBC.Driver" value="${driver}" /><property name="JDBC.ConnectionURL" value="${url}" /><property name="JDBC.Username" value="${username}" /><property name="JDBC.Password" value="${password}" /></dataSource></transactionManager><!-- 这里可以写多个实体的映射文件 --><sqlMap resource="com/ibatis/Student.xml" /></sqlMapConfig>

5. StudentDao.java

package com.ibatis.dao;import java.util.List;import com.ibatis.entity.Student;public interface StudentDao {/** * 添加学生信息 *  * @param student *            学生实体 * @return 返回是否添加成功 */public boolean addStudent(Student student);/** * 根据学生id删除学生信息 *  * @param id *            学生id * @return 删除是否成功 */public boolean deleteStudentById(int id);/** * 更新学生信息 *  * @param student *            学生实体 * @return 更新是否成功 */public boolean updateStudent(Student student);/** * 查询全部学生信息 *  * @return 返回学生列表 */public List<Student> selectAllStudent();/** * 根据学生姓名模糊查询学生信息 *  * @param name *            学生姓名 * @return 学生信息列表 */public List<Student> selectStudentByName(String name);/** * 根据学生id查询学生信息 *  * @param id *            学生id * @return 学生对象 */public Student selectStudentById(int id);}


6. StudentDaoImpl.java

package com.ibatis.daoimpl;import java.io.IOException;import java.io.Reader;import java.sql.SQLException;import java.util.List;import com.ibatis.dao.StudentDao;import com.ibatis.entity.Student;import com.ibatis.common.resources.Resources;import com.ibatis.sqlmap.client.SqlMapClient;import com.ibatis.sqlmap.client.SqlMapClientBuilder;public class StudentDaoImpl implements StudentDao {private static SqlMapClient sqlMapClient = null;// 读取配置文件static {try {Reader reader = Resources.getResourceAsReader("com/ibatis/SqlMapConfig.xml");sqlMapClient = SqlMapClientBuilder.buildSqlMapClient(reader);reader.close();} catch (IOException e) {e.printStackTrace();}}public boolean addStudent(Student student) {Object object = null;boolean flag = false;try {object = sqlMapClient.insert("addStudent", student);System.out.println("添加学生信息的返回值:" + object);} catch (SQLException e) {e.printStackTrace();}if (object != null) {flag = true;}return flag;}public boolean deleteStudentById(int id) {boolean flag = false;Object object = null;try {object = sqlMapClient.delete("deleteStudentById", id);System.out.println("删除学生信息的返回值:" + object + ",这里返回的是影响的行数");} catch (SQLException e) {e.printStackTrace();}if (object != null) {flag = true;}return flag;}public boolean updateStudent(Student student) {boolean flag = false;Object object = false;try {object = sqlMapClient.update("updateStudent", student);System.out.println("更新学生信息的返回值:" + object + ",返回影响的行数");} catch (SQLException e) {e.printStackTrace();}if (object != null) {flag = true;}return flag;}public List<Student> selectAllStudent() {List<Student> students = null;try {students = sqlMapClient.queryForList("selectAllStudent");} catch (SQLException e) {e.printStackTrace();}return students;}public List<Student> selectStudentByName(String name) {List<Student> students = null;try {students = sqlMapClient.queryForList("selectStudentByName",name);} catch (SQLException e) {e.printStackTrace();}return students;}public Student selectStudentById(int id) {Student student = null;try {student = (Student) sqlMapClient.queryForObject("selectStudentById", id);} catch (SQLException e) {e.printStackTrace();}return student;}}


7. TestIbatis.java

package com.ibatis.test;import java.sql.Date;import java.util.List;import com.ibatis.daoimpl.StudentDaoImpl;import com.ibatis.entity.Student;public class TestIbatis {public static void main(String[] args) {StudentDaoImpl studentDaoImpl = new StudentDaoImpl();System.out.println("测试插入");Student addStudent = new Student();addStudent.setName("李四");addStudent.setBirth(Date.valueOf("2011-09-02"));addStudent.setScore(88);System.out.println(studentDaoImpl.addStudent(addStudent));System.out.println("测试根据id查询");System.out.println(studentDaoImpl.selectStudentById(1));System.out.println("测试模糊查询");List<Student> mohuLists = studentDaoImpl.selectStudentByName("李");for (Student student : mohuLists) {System.out.println(student);}System.out.println("测试查询所有");List<Student> students = studentDaoImpl.selectAllStudent();for (Student student : students) {System.out.println(student);}System.out.println("根据id删除学生信息");System.out.println(studentDaoImpl.deleteStudentById(1));System.out.println("测试更新学生信息");Student updateStudent = new Student();updateStudent.setId(1);updateStudent.setName("李四1");updateStudent.setBirth(Date.valueOf("2011-08-07"));updateStudent.setScore(21);System.out.println(studentDaoImpl.updateStudent(updateStudent));}}

iBatis 的优缺点:

优点:

1、 减少代码量,简单;

2、 性能增强;

3、 Sql语句与程序代码分离;

4、 增强了移植性;

缺点:

1、 Hibernate 相比,sql 需要自己写;

2、 参数数量只能有一个,多个参数时不太方便;




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