搭建MyBatis開發環境,實現用戶表記錄數查詢 1、在MyEclipse中建立工程,導入MyBatis的jar包
二、建立MyBatis配置文件mybatis-config.xml配置數據庫信息
mybatis-config.xml文件
<?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"> <!-- 經過這個配置文件完成mybatis與數據庫的鏈接 --> <configuration> <!-- 引入 jdbc.properties 文件--> <properties resource="jdbc.properties"/><typeAliases></typeAliases> <environments default="development"> <environment id="development"> <!--配置事務管理,採用JDBC的事務管理 --> <transactionManager type="JDBC"></transactionManager> <!-- POOLED:mybatis自帶的數據源,JNDI:基於tomcat的數據源 --> <dataSource type="POOLED"> <property name="driver" value="${driver}"/> <property name="url" value="${url}"/> <property name="username" value="${username}"/> <property name="password" value="${password}"/> </dataSource> </environment> </environments> <!-- 將mapper文件加入到配置文件中 未來mapper文件不少因此是mappers --> <mappers> <mapper resource="cn/bdqn/dao/UserMapper.xml"/> </mappers> </configuration>
jdcb.properties文件(com.mysql.jdbc.Driver 必定要大寫)
driver=com.mysql.jdbc.Driver url=jdbc:mysql://localhost:3306/testdb username=root password=bdqn
mybatis-config.xml的頭文件:去dbf的文件開始位置找
mysql
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
a、複製mybatis-3.2.2\org\apache\ibatis\builder\xml下的2個文件(以下)放到你想要的地方(我直接放工程裏去)sql
![]()
b、而後在window-->prefenence-->xml-->xml catalog-->add-->config.dtd這個文件,而後key寫-//mybatis.org//DTD Config 3.0//EN-->確認後就能夠正常使用這個文件了
3、編寫實體類User
package cn.bdqn.pojo; public class User { private Integer id; private String username; private String userCode; private String userPassword; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getUserCode() { return userCode; } public void setUserCode(String userCode) { this.userCode = userCode; } public String getUserPassword() { return userPassword; } public void setUserPassword(String userPassword) { this.userPassword = userPassword; } }
測試類:數據庫
public class UserTest { private Logger logger = Logger.getLogger(UserTest.class); @Test public void countTest() { String resource = "mybatis-config.xml"; int count = 0; SqlSession sqlSession = null; try { //一、讀取配置文件(mybatis-config.xml)的輸入流 //引入包,是ibatis的包 InputStream is = Resources.getResourceAsStream(resource); System.out.println("is======"+is); //二、建立sqlSessionFactory對象,完成對配置文件的讀取(application做用域,建立完就不必銷燬)--一個就夠了(單例) SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is); System.out.println("factory======"+factory); //三、建立sqlSession對象(request做用域,用完後要關閉) sqlSession = factory.openSession(); System.out.println("sqlSession====="+sqlSession); System.out.println( sqlSession.selectOne("cn.bdqn.dao.UserMapper.count")); //四、調用mapper文件進行數據操做(調用以前必需要把mapper文件加入到mybatis-config.xml) count = sqlSession.selectOne("cn.bdqn.dao.UserMapper.count"); System.out.println("count===="+count); //打日誌用log4j.properties logger.debug("countTest--->"+count); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); }finally{ sqlSession.close(); } Assert.assertEquals(6, count); }
四、配置映射文件UserMapper.xmlapache
a、頭文件 :搜索:sqlsession就能夠找到探索映射sql語句下的頭文件
b、而後在window-->prefenence-->xml-->xml catalog-->add-->mapper.dtd這個文件,而後key寫-//mybatis.org//DTD Mapper 3.0//EN-->確認後就能夠正常使用這個文件了
<?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"> <!-- 若是我要調用mapper文件,就去拿到namespace+id(方法名)的名字就能夠訪問 --> <mapper namespace="cn.bdqn.dao.UserMapper"> <!-- id要惟一的,通常是下拉類的方法名 --> <!-- 返回的是什麼類型int --> <select id="count" resultType="int"> select count(1) from user </select> <!-- 增長 --> <!-- <insert id=""></insert> --> </mapper>