【mybatis】基础环境搭建

SQL脚本

CREATE TABLE `user`  (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `username` varchar(30) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
  `password` varchar(30) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
  `age` int(11) NULL DEFAULT NULL,
  `gender` varchar(6) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
  `addr` varchar(50) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 11 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = COMPACT;

INSERT INTO `user` VALUES (1, 'zhangsan', '123', 20, 'male', 'qd');
INSERT INTO `user` VALUES (2, 'lisi', '123', 21, 'male', 'bj');
INSERT INTO `user` VALUES (4, 'tom', '123', 19, 'male', 'nj');
INSERT INTO `user` VALUES (5, 'wangwu', '123', 20, 'male', 'sh');
INSERT INTO `user` VALUES (6, 'weihua', '111', 21, 'female', 'sz');

pom.xml

    4.0.0

    org.example
    mybatis02
    1.0-SNAPSHOT

    
        8
        8
    

    
        
            mysql
            mysql-connector-java
            5.1.47
        
        
            org.mybatis
            mybatis
            3.4.6
        
        
            
            junit
            junit
            4.13
            
            test
        
        
            
            log4j
            log4j
            1.2.17
        
    
    
    
        
            
                src/main/java
                
                    **/*.xml
                
            
        
    

创建表示用户的实体类User

package com.bean;
public class User {
    private Long id;
    private String username;
    private String password;
    private Integer age;
    private String gender;
    private String addr;
    
    //set、get
    //toString
}

log4j.properties

#
# Hibernate, Relational Persistence for Idiomatic Java
#
# License: GNU Lesser General Public License (LGPL), version 2.1 or later.
# See the lgpl.txt file in the root directory or .
#

### direct log messages to stdout ###
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.err
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n

### direct messages to file hibernate.log ###
#log4j.appender.file=org.apache.log4j.FileAppender
#log4j.appender.file.File=hibernate.log
#log4j.appender.file.layout=org.apache.log4j.PatternLayout
#log4j.appender.file.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n

### set log levels - for more verbose logging change 'info' to 'debug' ###

log4j.rootLogger=debug, stdout

这个文件编写不需要掌握，用的时候直接拷贝即可。

接口的名字我们一般命名为XxxMapper，所在的包命名为xxx.xxx.mapper，这是一种习惯。

当然也可以命名为XxxDao。

package com.mapper;
public interface UserMapper {
    List findAll();
}

    
        SELECT * FROM user
    

该文件在resources目录下

public class MyTest {
    private SqlSession sqlSession;
    private UserMapper userMapper;
    @Before
    public void init() throws IOException {
        //加载核心配置文件
        InputStream resourceAsStream = Resources.getResourceAsStream("SqlMapConfig.xml");
        //创建SqlSessionFactory
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(resourceAsStream);
        //获取连接
        sqlSession = factory.openSession();
        //创建接口的代理对象
        userMapper = sqlSession.getMapper(UserMapper.class);
    }

    @After
    public void destroy() {
        //关闭连接
        sqlSession.close();
    }

    @Test
    public void testFindById() {
        User user = userMapper.findById(1);
        System.out.println(user);
    }

    @Test
    public void testFindAll() {
        List users = userMapper.findAll();
        users.forEach(user -> System.out.println(user));
    }
}

运行测试方法，进行测试。