117 lines
3.6 KiB
Markdown
117 lines
3.6 KiB
Markdown
# R2DBC
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## Getting Started
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### 引入pom
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在spring boot项目中，如果要适配spring data r2dbc，可以引入如下pom依赖：
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```xml
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<dependency>
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<groupId>org.springframework.boot</groupId>
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<artifactId>spring-boot-starter-data-r2dbc</artifactId>
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</dependency>
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<dependency>
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<groupId>io.asyncer</groupId>
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<artifactId>r2dbc-mysql</artifactId>
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<version>1.4.1</version>
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</dependency>
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```
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### create pojo & create table
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之后，可以创建如下实体：
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```java
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public class Person {
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private final String id;
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private final String name;
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private final int age;
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public Person(String id, String name, int age) {
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this.id = id;
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this.name = name;
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this.age = age;
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}
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public String getId() {
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return id;
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}
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public String getName() {
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return name;
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}
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public int getAge() {
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return age;
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}
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@Override
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public String toString() {
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return "Person [id=" + id + ", name=" + name + ", age=" + age + "]";
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}
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}
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```
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创建table：
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```sql
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CREATE TABLE person(
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id VARCHAR(255) PRIMARY KEY,
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name VARCHAR(255),
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age INT
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);
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```
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### 声明ConnectionFactory
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```java
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@Configuration
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@Slf4j
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public class ConnectionFactoryConf extends AbstractR2dbcConfiguration {
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@Bean
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public ConnectionFactory connectionFactory() {
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// ConnectionFactories.get("jdbc:mysql://localhost:3306/innodb_demo?useSSL=false&rewriteBatchedStatements=true")
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// .
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ConnectionFactoryOptions options = ConnectionFactoryOptions.builder()
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.option(ConnectionFactoryOptions.HOST, "localhost")
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.option(ConnectionFactoryOptions.PORT, 3306)
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.option(ConnectionFactoryOptions.DRIVER, "mysql")
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.option(ConnectionFactoryOptions.USER, "rw_all_db")
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.option(ConnectionFactoryOptions.PASSWORD, "ab19971025")
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.option(ConnectionFactoryOptions.DATABASE, "asahi_schedule")
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.build();
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ConnectionPoolConfiguration poolConf = ConnectionPoolConfiguration.builder()
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.connectionFactory(ConnectionFactories.get(options))
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.maxSize(10)
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.validationQuery("SELECT 1")
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.build();
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return new ConnectionPool(poolConf);
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}
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}
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```
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在上述示例中，Conf类继承了AbstractR2dbcConfiguration类，相比于直接注入`connectionFactory`对象，通过AbstractR2dbcConfiguration注册能够提供ExceptionTranslator，将r2dbc中的异常翻译为DataAccessException。
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### 通过R2dbcEntityTemplate操作数据库
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通过entityTemplate操作数据库的示例如下：
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```java
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R2dbcEntityTemplate template = new R2dbcEntityTemplate(connectionFactory);
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template.getDatabaseClient().sql("CREATE TABLE person" +
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"(id VARCHAR(255) PRIMARY KEY," +
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"name VARCHAR(255)," +
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"age INT)")
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.fetch()
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.rowsUpdated()
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.as(StepVerifier::create)
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.expectNextCount(1)
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.verifyComplete();
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template.insert(Person.class)
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.using(new Person("joe", "Joe", 34))
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.as(StepVerifier::create)
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.expectNextCount(1)
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.verifyComplete();
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template.select(Person.class)
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.first()
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.doOnNext(it -> log.info(it))
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.as(StepVerifier::create)
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.expectNextCount(1)
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.verifyComplete();
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}
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```
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在上述示例中，pojo到table的映射会自动生效，并不需要额外的元数据。
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### Dialects
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spring data R2DBC会使用Dialect来对`特定数据库/driver的行为`进行封装。 |