java ssm框架学习——mybatis--1

发布时间：2023-05-16 17:00

MyBatis

MyBatis快速入门

PUBLIC "-//mybatis.org//DTD Config 3.0//EN"

"http://mybatis.org/dtd/mybatis-3-config.dtd">

1.2. 配置db.properties文件

jdbc.driver=com.mysql.jdbc.Driver

jdbc.url=jdbc\:mysql\://localhost\:3306/myfirstdb?characterEncoding\=utf-8

jdbc.username=root

jdbc.password=root

1.3. 配置log4j.properties文件

# Global logging configuration

log4j.rootLogger=DEBUG, stdout

# Console output...

log4j.appender.stdout=org.apache.log4j.ConsoleAppender

log4j.appender.stdout.layout=org.apache.log4j.PatternLayout

log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n

1.4. 创建bean类

public class User {

private Integer id;

private String username;

private String password;

private String sex;

2.1. 配置bean.xml

PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"

"http://mybatis.org/dtd/mybatis-3-mapper.dtd">

2.2. 配置文件中添加引用

2.3.1. bean.xml中定义查询的方法

2.3.2. 定义工厂测试准备方法

      
  // 会话工厂

private SqlSessionFactory sqlSessionFactory;

@Before

public void createSqlSessionFactory() throws IOException {

    // 配置文件

    String resource = "SqlMapConfig.xml";

    InputStream inputStream = Resources.getResourceAsStream(resource);

    // 使用SqlSessionFactoryBuilder从xml配置文件中创建SqlSessionFactory

    sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

2.3.3. 测试查询单个

@Test

public void testQuery() {

    SqlSession openSession = sqlSessionFactory.openSession();

    User user = openSession.selectOne("test.selectUserById", 5);

    System.out.println(user.toString());

    openSession.close();

2.3.4. 测试查询所有

@Test

public void testQueryList() {

    SqlSession openSession = sqlSessionFactory.openSession();

    List user = openSession.selectList("test.selectUser");

    for (User user2 : user) {

        System.out.println(user2.toString());

openSession.close();

2.3.5. 测试模糊查询

    insert into t_user

    (username,password,sex) values(#{username},#{password},#{sex});

@Test

public void testInsert() {

    SqlSession sqlSession = sqlSessionFactory.openSession();

    User user = new User("王五", "123", "男");

    sqlSession.insert("test.saveUser", user);

    sqlSession.commit();

    sqlSession.close();

2.3.6. 查询总结

#{}表示一个占位符号，
通过#{}可以实现preparedStatement向占位符中设置值，
自动进行java类型和jdbc类型转换，#{}括号中可以是value或其它名称
${}表示拼接sql串${}括号中只能是value。
传入的内容拼接在sql中且不进行jdbc类型转换。

parameterType：指定输入参数类型
resultType：指定输出结果类型

2.4. 测试添加

update t_user set

username=#{username},password=#{password},sex=#{sex} where id=#{id}

@Test

public void testUpdate() {

SqlSession sqlSession = sqlSessionFactory.openSession();

User user = new User("王小九", "1234", "女");

user.setId(5);

sqlSession.update("test.updateUser", user);

sqlSession.commit();

sqlSession.close();

2.5. 测试修改

delete from t_user where id=#{a}

@Test

public void testDelete() {

SqlSession sqlSession = sqlSessionFactory.openSession();

sqlSession.delete("test.deleteUser", 1);

sqlSession.commit();

sqlSession.close();

2.6. 测试删除

delete from t_user where id=#{a}

@Test

public void testDelete() {

SqlSession sqlSession = sqlSessionFactory.openSession();

sqlSession.delete("test.deleteUser", 1);

sqlSession.commit();

sqlSession.close();

2.7. 插入数据并获取id

        select

        LAST_INSERT_ID()

    insert into t_user

    (username,sex,age) values

    (#{username},#{sex},#{age});

2.8. 插入UUID类型的主键

        select

        uuid()

    insert into t_person

    (id,username,sex,age) values

    (#{id},#{username},#{sex},#{age});