1、整合druid数据源

1.1 单数据源配置

<dependency>
   <groupId>com.alibaba</groupId>
   <artifactId>druid-spring-boot-starter</artifactId>
   <version>1.1.10</version>
</dependency>
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@Configuration
public class DruidConfig {
    @ConfigurationProperties(prefix = "spring.datasource")
    @Bean
    public DataSource druid(){
        return new DruidDataSource();
    }
    //配置Druid的监控
//1、配置一个管理后台的Servlet
    @Bean
    public ServletRegistrationBean statViewServlet(){
        ServletRegistrationBean bean = new ServletRegistrationBean(new StatViewServlet(),
                "/druid/*");
        Map<String,String> initParams = new HashMap<>();
        initParams.put("loginUsername","admin");
        initParams.put("loginPassword","123456");
        initParams.put("allow","");//默认就是允许所有访问
        initParams.put("deny","192.168.15.21");
        bean.setInitParameters(initParams);
        return bean;
    }
    //2、配置一个web监控的filter
    @Bean
    public FilterRegistrationBean webStatFilter(){
        FilterRegistrationBean bean = new FilterRegistrationBean();
        bean.setFilter(new WebStatFilter());
        Map<String,String> initParams = new HashMap<>();
        initParams.put("exclusions","*.js,*.css,/druid/*");
        bean.setInitParameters(initParams);
        bean.setUrlPatterns(Arrays.asList("/*"));
        return bean;
    }
}

spring.datasource.druid.initial-size=10
spring.datasource.druid.min-idle=10
spring.datasource.druid.max-active=15
spring.datasource.druid.filters=stat,wall,log4j2
spring.datasource.druid.filter.config.enabled=true
spring.datasource.druid.filter.stat.enabled=true
spring.datasource.druid.filter.stat.db-type=mysql
spring.datasource.druid.filter.stat.log-slow-sql=true
spring.datasource.druid.filter.stat.slow-sql-millis=2000
spring.datasource.druid.filter.wall.enabled=true
spring.datasource.druid.filter.wall.db-type=mysql
spring.datasource.druid.filter.wall.config.delete-allow=true
spring.datasource.druid.filter.wall.config.drop-table-allow=false
spring.datasource.druid.filter.log4j2.enabled=true
spring.datasource.druid.stat-view-servlet.enabled=true
spring.datasource.druid.stat-view-servlet.url-pattern=/druid/*
spring.datasource.druid.stat-view-servlet.login-username=admin
spring.datasource.druid.stat-view-servlet.login-password=admin@zt3000
spring.datasource.druid.stat-view-servlet.use-global-data-source-stat=true
spring.datasource.druid.web-stat-filter.enabled=true
spring.datasource.druid.web-stat-filter.exclusions=*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*
spring.datasource.druid.aop-patterns=com.xxxxxxxxxxx.bmp.dao.*
spring.datasource.druid.driver-class-name=com.mysql.jdbc.Driver

1.2 多数据源配置

spring:
 # 数据源配置
  datasource:
    ds1: #数据源1
      driver-class-name: com.mysql.jdbc.Driver # mysql的驱动你可以配置别的关系型数据库
      url: jdbc:mysql://ip:3306/db1 #数据源地址
      username: root # 用户名
      password: root # 密码
    ds2: # 数据源2
      driver-class-name: com.mysql.jdbc.Driver # mysql的驱动你可以配置别的关系型数据库
      url: jdbc:mysql://ip:3307/db2#数据源地址
      username: root # 用户名
      password: root # 密码
/**
 * 多数据源配置
 */
@Configuration
public class DataSourceConfig {
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    //主数据源配置 ds1数据源
    @Primary
    @Bean(name = "ds1DataSourceProperties")
    @ConfigurationProperties(prefix = "spring.datasource.ds1")
    public DataSourceProperties ds1DataSourceProperties() {
        return new DataSourceProperties();
    }
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    //主数据源 ds1数据源
    @Primary
    @Bean(name = "ds1DataSource")
    public DataSource ds1DataSource(@Qualifier("ds1DataSourceProperties") DataSourceProperties dataSourceProperties) {
        return dataSourceProperties.initializeDataSourceBuilder().build();
    }
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    //第二个ds2数据源配置
    @Bean(name = "ds2DataSourceProperties")
    @ConfigurationProperties(prefix = "spring.datasource.ds2")
    public DataSourceProperties ds2DataSourceProperties() {
        return new DataSourceProperties();
    }
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    //第二个ds2数据源
    @Bean("ds2DataSource")
    public DataSource ds2DataSource(@Qualifier("ds2DataSourceProperties") DataSourceProperties dataSourceProperties) {
        return dataSourceProperties.initializeDataSourceBuilder().build();
    }
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}

2、整合Mybatis

2.1 简单整合

2.1.1 添加依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.0.0</version>
</dependency>
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid-spring-boot-starter</artifactId>
    <version>1.1.10</version>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.28</version>
    <scope>runtime</scope>
</dependency>

2.1.2 配置数据源

spring.datasource.url=jdbc:mysql:///testdb?useUnicode=true&characterEncoding=utf-8
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource

2.1.3 创建Mapper （基于注解）

public interface UserMapper {
    @Select("select * from user")
    List<User> getAllUsers();
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    @Results({
            @Result(property = "id", column = "id"),
            @Result(property = "username", column = "u"),
            @Result(property = "address", column = "a")
    })
    @Select("select username as u,address as a,id as id from user where id=#{id}")
    User getUserById(Long id);
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    @Select("select * from user where username like concat(‘%‘,#{name},‘%‘)")
    List<User> getUsersByName(String name);
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    @Insert({"insert into user(username,address) values(#{username},#{address})"})
    @SelectKey(statement = "select last_insert_id()", keyProperty = "id", before = false, resultType = Integer.class)
    Integer addUser(User user);
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    @Update("update user set username=#{username},address=#{address} where id=#{id}")
    Integer updateUserById(User user);
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    @Delete("delete from user where id=#{id}")
    Integer deleteUserById(Integer id);
}

2.1.4 创建Mapper (基于XML文件)

public interface UserMapper {
    List<User> getAllUser();
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    Integer addUser(User user);
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    Integer updateUserById(User user);
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    Integer deleteUserById(Integer id);
}

<?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.boot.mybatis.mapper.UserMapper">
    <select id="getAllUser" resultType="org.sang.mybatis.model.User">
        select * from t_user;
    </select>
    <insert id="addUser" parameterType="org.sang.mybatis.model.User">
        insert into user (username,address) values (#{username},#{address});
    </insert>
    <update id="updateUserById" parameterType="org.sang.mybatis.model.User">
        update user set username=#{username},address=#{address} where id=#{id}
    </update>
    <delete id="deleteUserById">
        delete from user where id=#{id}
    </delete>
</mapper>

2.1.5 Mapper配置文件位置

2.1.5.1 放到UserMapper类同级

必须配置资源插件，因为boot默认只会加载resources的目录文件

<build>
    <resources>
        <resource>
            <directory>src/main/java</directory>
            <includes>
                <include>**/*.xml</include>
            </includes>
        </resource>
        <resource>
            <directory>src/main/resources</directory>
        </resource>
    </resources>
</build>

2.1.5.1 放到resources文件夹中指定的目录

在application.properties中告诉mybatis去哪里扫描mapper：

mybatis.mapper-locations=classpath:mapper/*.xml

2.2 逆向工程

2.2.1 添加逆向工程插件

<plugin>
        <groupId>org.mybatis.generator</groupId>
        <artifactId>mybatis-generator-maven-plugin</artifactId>
        <version>1.4.0</version>
        <configuration>
            <configurationFile>src/main/resources/generatorConfig.xml</configurationFile>
            <verbose>true</verbose>
            <overwrite>true</overwrite>
        </configuration>
    </plugin>

2.2.2 指定逆向工程配置文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration
        PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
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<generatorConfiguration>
    <classPathEntry
            location="D:\installed\devtools\maven\repository\mysql\mysql-connector-java\5.1.38\mysql-connector-java-5.1.38.jar"/>
    <context id="mySQL" targetRuntime="MyBatis3">
        <commentGenerator>
            <property name="suppressDate" value="true"/>
            <property name="suppressAllComments" value="true"/>
        </commentGenerator>
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        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://localhost:3306/2pc" userId="root"
                        password="123">
        </jdbcConnection>
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        <javaTypeResolver>
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>
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        <!--实体生成的配置-->
        <javaModelGenerator targetPackage="com.mmren.edu.domain"
                            targetProject=".\src\main\java">
            <property name="enableSubPackages" value="true"/>
            <property name="trimStrings" value="true"/>
        </javaModelGenerator>
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        <!--mapper接口生成配置-->
        <sqlMapGenerator targetPackage="com.mmren.edu.mapper"
                         targetProject=".\src\main\java">
            <property name="enableSubPackages" value="true"/>
        </sqlMapGenerator>
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        <!--mapper对应的映射文件生成配置-->
        <javaClientGenerator type="XMLMAPPER"
                             targetPackage="com.mmren.edu.mapper" targetProject=".\src\main\java">
            <property name="enableSubPackages" value="true"/>
        </javaClientGenerator>
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        <!--表对应实体名称的配置-->
        <table tableName="t_order" domainObjectName="OrderInfo"
               enableCountByExample="false"
               enableUpdateByExample="false"
               enableDeleteByExample="false"
               enableSelectByExample="false"
               selectByExampleQueryId="false"/>
    </context>
</generatorConfiguration>

生成实体，mapper，mapper配置文件

2.3 通用Mapper

通用Mapper就是为了解决单表增删改查，基于Mybatis的插件。开发人员不需要编写SQL，不需要在DAO中增加方法，只要写好实体类，就能支持相应的增删改查方法。

2.3.1 添加依赖

<dependency>
    <groupId>tk.mybatis</groupId>
    <artifactId>mapper-spring-boot-starter</artifactId>
    <version>2.1.5</version>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.38</version>
</dependency>

2.3.2 添加实体

@Table(name="t_user") // 配置实体映射的表名
public class User implements Serializable {
    private static final long serialVersionUID = -37900582537861695L;
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    @Id // 必须配置不配置，如果使用通过ID查询的时候会把所有字段当作条件进行查询
    private Integer userId;
    
    private String userName;
    
    private Integer userAge;
    
    private Date userBirth;
    
    private Date createTime;
    
    private Date updateTime;
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    public Integer getUserId() {
        return userId;
    }
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    public void setUserId(Integer userId) {
        this.userId = userId;
    }
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    public String getUserName() {
        return userName;
    }
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    public void setUserName(String userName) {
        this.userName = userName;
    }
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    public Integer getUserAge() {
        return userAge;
    }
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    public void setUserAge(Integer userAge) {
        this.userAge = userAge;
    }
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    public Date getUserBirth() {
        return userBirth;
    }
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    public void setUserBirth(Date userBirth) {
        this.userBirth = userBirth;
    }
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    public Date getCreateTime() {
        return createTime;
    }
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    public void setCreateTime(Date createTime) {
        this.createTime = createTime;
    }
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    public Date getUpdateTime() {
        return updateTime;
    }
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    public void setUpdateTime(Date updateTime) {
        this.updateTime = updateTime;
    }
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}

2.3.3 配置Mapper

@Component
@org.apache.ibatis.annotations.Mapper
public interface UserMapper extends Mapper<User> {
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}

2.3.4 配置数据源

spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql:///test1?useSSL=false
    username: root
    password: 123
mybatis:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

2.3.5 编写测试用例

/**
 * 欢迎来到牧码人教育，做Java我们是专业的
 *
 * @创建人： 牧码人教育-Gerry
 * @创建时间： 2020-4-21
 * @功能描述：
 */
public class MapperTests extends DemoApplicationTests {
    @Autowired
    private UserMapper userMapper;
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    ///////////////////////// 查询 测试 /////////////////////
    // 测试根据ID查询，必须在注解字段标记@Id
    @Test
    public void testSelectById() throws Exception {
        User user = userMapper.selectByPrimaryKey(30001);
        convertToJson(user);
    }
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    // 测试根据指定的列进行查询
    @Test
    public void testSelectByColumns() throws Exception {
        // 创建查询条件对象
        Example example = new Example(User.class);
        example.and().andEqualTo("userName","牧码人")
                .andEqualTo("updateTime","2020-04-21 23:42:13.0");
       /* Example.Criteria criteria = example.createCriteria();
        criteria.andEqualTo("userName","牧码人")
                .andEqualTo("updateTime","2020-04-21 23:42:13.0");*/
        User user = userMapper.selectOneByExample(example);
        convertToJson(user);
    }
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    // 测试模糊查询后排序
    @Test
    public void testSelectByColumnsForLike() throws Exception {
        // 创建查询条件对象
        Example example = new Example(User.class);
        example.and().andLike("userName","%人%")
                .andBetween("userAge",1,100);
        example.orderBy("userId").desc();
       /* Example.Criteria criteria = example.createCriteria();
        criteria.andEqualTo("userName","牧码人")
                .andEqualTo("updateTime","2020-04-21 23:42:13.0");*/
        List<User> users = userMapper.selectByExample(example);
        convertToJson(users);
    }
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    // 自定义SQL语句查询
    @Test
    public void testSelectByCustomSql() throws Exception {
        // 创建查询条件对象
        Example example = new Example(User.class);
        example.and().andLike("userName","%人%")
                .andBetween("userAge",1,100)
                // 自定义拼接的SQL
                .andCondition("create_time=","2020-04-22 00:13:58")
                // 自定义SQL语句
                .andCondition("update_time=‘2020-04-22 00:13:58‘");
        example.orderBy("userId").desc();
        List<User> users = userMapper.selectByExample(example);
        convertToJson(users);
    }
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    // 分页查询(全部)
    @Test
    public void testSelectByPage() throws Exception {
        RowBounds rowBounds = new RowBounds(((1-1)*2),2);
        List<User