MyBatis的基础查询

淩亂°似流年 2023-07-04 11:10 14阅读 0赞

#### 1，导入MyBatis使用的依赖 ####

<dependencies>
    
                
                <dependency>
                    <groupId>org.mybatis</groupId>
                    <artifactId>mybatis</artifactId>
                    <version>3.4.6</version>
                </dependency>
    
                <dependency>
                    <groupId>mysql</groupId>
                    <artifactId>mysql-connector-java</artifactId>
                    <version>5.1.46</version>
                    <scope>runtime</scope>
                </dependency>
                <dependency>
                    <groupId>junit</groupId>
                    <artifactId>junit</artifactId>
                    <version>4.12</version>
                    <scope>test</scope>
                </dependency>
            </dependencies>

#### 2，MyBatis的配置类SqlMapConfig.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="abc">
    
            <environment id="abc">
                
                <transactionManager type="JDBC"></transactionManager>
    
                
                <dataSource type="POOLED">
                    <property name="driver" value="com.mysql.jdbc.Driver"/>
                    <property name="url" value="jdbc:mysql:///db_shopping?useUnicode=true&characterEncoding=UTF8"/>
                    <property name="username" value="root"/>
                    <property name="password" value="qishimeiyoumima"/>
                </dataSource>
            </environment>
    
        </environments>
    
    
        <mappers>
            <mapper resource="User.xml"></mapper>
        </mappers>
    
    </configuration>

#### 3，pojo类User.class ####

public class User {
        
        private  int id;
        private String username;
        private String password;
        private String email;
        private String gender;
        private int flag;
        private int role;
        private String code;
    
    
        public int getId() {
        
            return id;
        }
    
        public void setId(int id) {
        
            this.id = id;
        }
    
        public String getUsername() {
        
            return username;
        }
    
        public void setUsername(String username) {
        
            this.username = username;
        }
    
        public String getPassword() {
        
            return password;
        }
    
        public void setPassword(String password) {
        
            this.password = password;
        }
    
        public String getEmail() {
        
            return email;
        }
    
        public void setEmail(String email) {
        
            this.email = email;
        }
    
        public String getGender() {
        
            return gender;
        }
    
        public void setGender(String gender) {
        
            this.gender = gender;
        }
    
        public int getFlag() {
        
            return flag;
        }
    
        public void setFlag(int flag) {
        
            this.flag = flag;
        }
    
        public int getRole() {
        
            return role;
        }
    
        public void setRole(int role) {
        
            this.role = role;
        }
    
        public String getCode() {
        
            return code;
        }
    
        public void setCode(String code) {
        
            this.code = code;
        }
    
    
        @Override
        public String toString() {
        
            return "User{" +
                    "id=" + id +
                    ", username='" + username + '\'' +
                    ", password='" + password + '\'' +
                    ", email='" + email + '\'' +
                    ", gender='" + gender + '\'' +
                    ", flag=" + flag +
                    ", role=" + role +
                    ", code='" + code + '\'' +
                    '}';
        }
    
    }

#### 4，User.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="test">
        
        <select id="findUserById" parameterType="int" resultType="com.qianfeng.mybatis.pojo.User">
          SELECT * FROM tb_user WHERE id=#{id}
        </select>
        
        <select id="findUserByName" parameterType="string" resultType="person.david.mybatis.pojo.User">
    
            SELECT * FROM tb_user WHERE username like '%${value}%'
        </select>
        
        <insert id="insertUser" parameterType="person.david.mybatis.pojo.User">
            INSERT INTO tb_user (username,password,email,gender,flag,role,code) VALUES (#{username},#{password},#{email},#{gender},#{flag},#{role},#{code})
    
        </insert>
    	
        <insert id="insertUser1" parameterType="person.david.mybatis.pojo.User">
    
          <selectKey resultType="int" keyProperty="id" order="AFTER">
    
              SELECT LAST_INSERT_ID()
          </selectKey>
    
            INSERT INTO tb_user (iusername,password,email,gender,flag,role,code) VALUES (#{username},#{password},#{email},#{gender},#{flag},#{role},#{code})
    
        </insert>
    
        <insert id="insertUser2" parameterType="person.david.mybatis.pojo.TestPojo">
    
            <selectKey resultType="string" keyProperty="id" order="BEFORE">
    
                SELECT UUID()
            </selectKey>
    
            INSERT INTO db_test (id) VALUES (#{id})
    
        </insert>
    
        
        <delete id="dasdasd" parameterType="string">
            DELETE  from db_test where id =#{id}
    
        </delete>
    
    
        <update id="update" parameterType="person.david.mybatis.pojo.User">
    
          update tb_user set username=#{username} where id =#{id}
    
        </update>
    
    </mapper>

#### 5，测试类TestMain.class ####

public class TestMain {
        
    
        private SqlSessionFactory sqlSessionFactory;
    
        @Before
        public void before() throws IOException {
        
            InputStream inputStream= Resources.getResourceAsStream("SqlMapConfig.xml");//将配置文件通过io流的方式打开 /WEB-INF/classes
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);//创建sqlsession工厂
        }
    
        @Test
        public void test1() throws IOException {
        
            //如果创建对象加载sql语句
            //链接数据库
            InputStream inputStream= Resources.getResourceAsStream("SqlMapConfig.xml");//将配置文件通过io流的方式打开 /WEB-INF/classes
            SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);//创建sqlsession工厂
            //获取链接
            SqlSession sqlSession = sqlSessionFactory.openSession();//数据库的链接
            User user = sqlSession.selectOne("test.findUserById", 5);//调用sql. 参数1 的格式是 xml文件的 namespace.id
            System.err.println(user);
            sqlSession.close();//关闭链接
    
        }
     }