mybaties的dao层实现-接口代理方式代码实现

核心配置文件-------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="development">
        <environment id="development">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"></property>
                <property name="url" value="jdbc:mysql://localhost:3306/test"></property>
                <property name="username" value="root"></property>
                <property name="password" value="123456"></property>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="com.itheima.mapper/UserMapper.xml"></mapper>
    </mappers>
</configuration>

映射配置文件-------UserMapper.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="com.itheima.mapper.UserMapper">
    <select id="findByCondition" parameterType="com.itheima.domain.User" resultType="com.itheima.domain.User">
        select * from user  where id=#{id} and username=#{username};
    </select>
</mapper>

创建实体类User并为其添加getter/setter方法以及toString()用法

package com.itheima.domain;

/**
 * @UpdateRemark: 更新说明
 * @Version: 1.0
 */

public class User {
    private int id;
    private int age;
    private String username;
    private String PASSWORD;
    private String email;
    private String sex;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    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 getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }


    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", age=" + age +
                ", username='" + username + '\'' +
                ", PASSWORD='" + PASSWORD + '\'' +
                ", email='" + email + '\'' +
                ", sex='" + sex + '\'' +
                '}';
    }
}

mapper下创建接口 UserMapper

package com.itheima.mapper;

import com.itheima.domain.User;

import java.util.List;

/**

 * @UpdateRemark: 更新说明
 * @Version: 1.0
 */
public interface UserMapper {
    public List<User> findByCondition(User user);
}

test下创建测试Demo
mybaties框架生成的userMapper接口的实现类

UserMapper mapper = sqlSession.getMapper(UserMapper.class);

package com.itheima.test;

import com.itheima.domain.User;
import com.itheima.mapper.UserMapper;
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.junit.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

/**

 * @UpdateRemark: 更新说明
 * @Version: 1.0
 */

public class Demo {
    @Test
public void test1() throws IOException {
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = sessionFactory.openSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        User user = new User();
        user.setId(1);
       user.setUsername("张老师");
        List<User> byCondition = mapper.findByCondition(user);
        System.out.println(byCondition);
    }
}

另外涉及到mysql、@test、mybaties、log4j所以在pom文件中我们需要引入相对应的坐标

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>Mybaties</artifactId>
        <groupId>Mybaties</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>a</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>
    <dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.32</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.1</version>

        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
    </dependencies>

</project>

Running~

最后强调一下。Coding时要注意开头我写的需要注意的地方，方法名，接口名，Namespace等 如果出现SQL syntax，那么你就需要看一下映射配置文件中你的SQL语句是否规范，以及命名等地方寻找问题

Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax;

我不能保证我所说的都是对的，但我能保证每一篇都是用心去写的，我始终认同: “分享的越多，你的价值增值越大”，我们一同在分享中进步，在分享中成长，越努力越幸运。再分享一句话“十年前你是谁，一年前你是谁，甚至昨天你是谁，都不重要。重要的是，今天你是谁，以及明天你将成为谁。”
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