java——mybatis——Mybatis注解开发——@Select查询——查询所有数据

野性酷女 2024-03-31 14:58 119阅读 0赞

pom.xml配置：

<?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">
        <modelVersion>4.0.0</modelVersion>
    
        <groupId>org.example</groupId>
        <artifactId>sunxl</artifactId>
        <version>1.0-SNAPSHOT</version>
    
        <properties>
            <maven.compiler.source>8</maven.compiler.source>
            <maven.compiler.target>8</maven.compiler.target>
        </properties>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>
    
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.27</version>
        </dependency>
    
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.1</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>2.17.2</version>
        </dependency>
    </dependencies>
    </project>

![8961dc6ff07291e40667089a0d2d4672.png][]

mybatis-config.xml配置：

<?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>
    
        <typeAliases>
            <package name="com.sunxl.pojo"/>
        </typeAliases>
        
        <environments default="development">
            <environment id="development">
                
                <transactionManager type="JDBC" />
                <dataSource type="POOLED">
                    
                    <property name="driver" value="com.mysql.jdbc.Driver" />
                    
                    <property name="url" value="jdbc:mysql://localhost:3306/mysql8?characterEncoding=utf8" />
                    <property name="username" value="root" />
                    <property name="password" value="123456" />
                </dataSource>
            </environment>
        </environments>
        
        <mappers>
            <package name="com.sunxl.dao"></package>
        </mappers>
    </configuration>

![611676602bcdac9969ebe6ae5f97802e.png][]

user的pojo类：

package com.sunxl.pojo;
    
    public class User {
    
        Integer id;
        String name;
        Integer age;
    
        public Integer getId() {
            return id;
        }
    
        public void setId(Integer id) {
            this.id = id;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public Integer getAge() {
            return age;
        }
    
        public void setAge(Integer age) {
            this.age = age;
        }
    
        @Override
        public String toString() {
            return "Users{" +
                    "id=" + id +
                    ", name='" + name + '\'' +
                    ", age=" + age +
                    '}';
        }
    
    }

![f328d52b98d3707528cb7c07e6d4f8b0.png][]

DAO接口文件：

package com.sunxl.dao;
    
    import com.sunxl.pojo.User;
    import org.apache.ibatis.annotations.Select;
    
    import java.util.List;
    
    public interface UserDao {
    
        @Select("select * from users")
        List<User> findAll();
    
    //    int saveUser(User user);
    //
    //    int updateUser(User user);
    //
    //    int deleteUser(Integer id);
    //
    //    User findById(Integer id);
    //
    //    List<User> findByName(String name);
    //
    //    int findTotal();
    //
    //    int saveInsertUser(User user);
    
    }

![798f6a5f3f23087346545c2157ec2fae.png][]

测试结果：

import com.sunxl.dao.UserDao;
    import com.sunxl.pojo.User;
    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 java.io.IOException;
    import java.io.InputStream;
    import java.util.List;
    
    public class MybatisTest {
    
        public static void main(String[] args) throws IOException {
    
            InputStream config = Resources.getResourceAsStream("mybatis-config.xml");
    
            SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
            SqlSessionFactory factory = builder.build(config);
            SqlSession ss = factory.openSession();
            UserDao userdao = ss.getMapper(UserDao.class);
    
            
            List<User> users = userdao.findAll();
    
            for (User user: users){
                System.out.println(user);
            }
    
            
            ss.commit();
            ss.close();
            config.close();
    
    
        }
    }

![612081138cc314312621c8200493bcc5.png][]

![b935a11ec35e1481aa212c4be1320acf.png][]

表结构：

![9bdeac3a0b7746ee9a48b49dd6da3283.png][]

[8961dc6ff07291e40667089a0d2d4672.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/23572631721943489fdd3c6cc4f84f83.png
[611676602bcdac9969ebe6ae5f97802e.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/1ed4d1f4caa84bd5a4e9ecc6ccc5b918.png
[f328d52b98d3707528cb7c07e6d4f8b0.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/5c5274ca4e4143708d6102d586277582.png
[798f6a5f3f23087346545c2157ec2fae.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/0e2f7783c36140819cb51f206f9db6ab.png
[612081138cc314312621c8200493bcc5.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/2adeac46c24b41a78fd5c1bd46ccb30a.png
[b935a11ec35e1481aa212c4be1320acf.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/e3620df7c25e4665b8eb6ddb65944eb5.png
[9bdeac3a0b7746ee9a48b49dd6da3283.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/646eff08684a427e8ca5476645e2f3c7.png