Java_myBatis入門寫法

一.整體步驟

1.讀取全局配置文件“SqlMapConfig.xml”

2.用SqlSessionFactoryBuilder來創建一個SqlSessionFactory

3.用創建好的SqlSessionFactory創建一個SqlSession

4.用創建好的SqlSession來讀取對應的映射配置文件“Mapper1.xml”，並傳入參數

5.返回結果

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二.具體步驟

1.新建maven項目

eclipse菜單找到“File”->"new"->"Project",選擇Maven Project

2.在配置文件pom.xml下的denpencies添加denpency

mybatis的jar包和mysql的jdbc驅動

<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis</artifactId>
    <version>3.4.6</version>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.35</version>
</dependency>

3.在src/main下新建資源文件夾"resources",並添加SqlMapConfig.xml、具體映射配置文件Mapper.xml和數據庫參數文件db.properties

SqlMapConfig.xml源碼:

<?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>
  <properties resource="db.properties"></properties>
  <environments default="development">
    <environment id="development">
      <transactionManager type="JDBC"/>
      <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>
  <mappers>
    <mapper resource="StudentMapper.xml"/>
  </mappers>
</configuration>

 db.properties的源碼：

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf8
username=root
password=123456

Mapper.xml的源碼

<?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="test">
    <select id="selectPerson" parameterType="int" resultType="com.mavenTest.mybatis_test.Person">
        select * from Persons_table where id = #{id}
    </select>
</mapper>

#{}：是經過處理的相當於JDBC的PreparedStatement，簡單類型時“{}”里可以寫任意名字（甚至是中文）

${}：是原樣輸出相當於JDBC的Statement，簡單類型時“{}”里必須寫“value”

4.在main/java下的任意jar包中創建一個pojo，這里例如是Person.class（注意對應好上面的resultType的路徑）

public class Person{
    private int id;
    private String name;
    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;
    }
}

5.在java/main的任意jar包創建一個任意類

 

public class pratise {
    public static void main(String[] args) throws IOException{
        // 讀取全局配置文件
        InputStream is = Resources.getResourceAsStream("SqlMapConfig.xml");
        // 用SqlSessionFactoryBuilder來創建SqlSessionFactory實例
        SqlSessionFactory ssf = new SqlSessionFactoryBuilder().build(is);
        // 用SqlSessionFactory實例來創建SqlSession實例
        SqlSession ss = ssf.openSession();
        // 通過SqlSession實例來查詢映射配置文件，然后傳入參數，執行sql語句
        Student s = ss.selectOne("selectStudent", 827);
        // 關閉SqlSession實例
        ss.close();
        System.out.println(s.getName());
    }
}

 

 

 

 這樣就已經可以實現數據庫語句的調用了