數據庫事務操作 · springboot官方文檔中文版

# 管理交易本指南將引導您完成使用非侵入式事務包裝數據庫操作的過程。 ## 你會建立什么您將構建一個簡單的JDBC應用程序，在該應用程序中，您無需編寫即可使數據庫操作具有事務性 [專門的JDBC代碼](https://docs.oracle.com/javase/tutorial/jdbc/basics/transactions.html#commit_transactions) 。 ## 你需要什么 * 約15分鐘 * 最喜歡的文本編輯器或IDE * [JDK 1.8](http://www.oracle.com/technetwork/java/javase/downloads/index.html) 或更高版本 * [Gradle 4+](http://www.gradle.org/downloads) 或 [Maven 3.2+](https://maven.apache.org/download.cgi) * 您還可以將代碼直接導入到IDE中： * [彈簧工具套件（STS）](https://spring.io/guides/gs/sts) * [IntelliJ IDEA](https://spring.io/guides/gs/intellij-idea/) ## 如何完成本指南像大多數Spring 一樣 [入門指南](https://spring.io/guides) ，您可以從頭開始并完成每個步驟，也可以繞過您已經熟悉的基本設置步驟。無論哪種方式，您最終都可以使用代碼。要 **從頭開始** ，請繼續進行“ [從Spring Initializr開始”](https://spring.io/guides/gs/managing-transactions/#scratch) 。要 **跳過基礎知識** ，請執行以下操作： * [下載](https://github.com/spring-guides/gs-managing-transactions/archive/master.zip) 并解壓縮本指南的源存儲庫，或使用對其進行克隆 [Git](https://spring.io/understanding/Git) ： `git clone [https://github.com/spring-guides/gs-managing-transactions.git](https://github.com/spring-guides/gs-managing-transactions.git)` * 光盤進入 `gs-managing-transactions/initial` * 繼續 [創建預訂服務](https://spring.io/guides/gs/managing-transactions/#initial) 。 **完成后** ，您可以根據中的代碼檢查結果 `gs-managing-transactions/complete`. ## 從Spring Initializr開始如果您使用Maven，請訪問 [Spring Initializr](https://start.spring.io/#!type=maven-project&language=java&platformVersion=2.4.3.RELEASE&packaging=jar&jvmVersion=1.8&groupId=com.example&artifactId=managing-transactions&name=managing-transactions&description=Demo%20project%20for%20Spring%20Boot&packageName=com.example.managing-transactions&dependencies=data-jdbc,h2) 以生成具有所需依賴項的新項目（Spring Data JDBC和H2數據庫）。以下清單顯示了 `pom.xml` 選擇Maven時創建的文件： ~~~ <?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 https://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.4.3</version> <relativePath/>  </parent> <groupId>com.example</groupId> <artifactId>managing-transactions</artifactId> <version>0.0.1-SNAPSHOT</version> <name>managing-transactions</name> <description>Demo project for Spring Boot</description> <properties> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jdbc</artifactId> </dependency> <dependency> <groupId>com.h2database</groupId> <artifactId>h2</artifactId> <scope>runtime</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project> ~~~ 如果使用Gradle，請訪問 [Spring Initializr](https://start.spring.io/#!type=gradle-project&language=java&platformVersion=2.4.3.RELEASE&packaging=jar&jvmVersion=1.8&groupId=com.example&artifactId=managing-transactions&name=managing-transactions&description=Demo%20project%20for%20Spring%20Boot&packageName=com.example.managing-transactions&dependencies=data-jdbc,h2) 以生成具有所需依賴項的新項目（Spring Data JDBC和H2數據庫）。以下清單顯示了 `build.gradle` 選擇Gradle時創建的文件： ~~~ plugins { id 'org.springframework.boot' version '2.4.3' id 'io.spring.dependency-management' version '1.0.11.RELEASE' id 'java' } group = 'com.example' version = '0.0.1-SNAPSHOT' sourceCompatibility = '1.8' repositories { mavenCentral() } dependencies { implementation 'org.springframework.boot:spring-boot-starter-data-jdbc' runtimeOnly 'com.h2database:h2' testImplementation 'org.springframework.boot:spring-boot-starter-test' } test { useJUnitPlatform() } ~~~ ### 手動初始化（可選）如果要手動初始化項目而不是使用前面顯示的鏈接，請按照以下步驟操作： 1. 導航到 [https://start.spring.io](https://start.spring.io) 。該服務提取應用程序所需的所有依賴關系，并為您完成大部分設置。 2. 選擇Gradle或Maven以及您要使用的語言。本指南假定您選擇了Java。 3. 單擊 **Dependencies，** 然后選擇 **Spring Data JDBC** 和 **H2 Database** 。 4. 點擊 **生成** 。 5. 下載生成的ZIP文件，該文件是使用您的選擇配置的Web應用程序的存檔。如果您的IDE集成了Spring Initializr，則可以從IDE中完成此過程。 ## 創建預訂服務首先，您需要使用 `BookingService`類以創建基于JDBC的服務，該服務按名稱將人預訂到系統中。以下清單（來自 `src/main/java/com/example/managingtransactions/BookingService.java`）顯示了如何執行此操作： ~~~ package com.example.managingtransactions; import java.util.List; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.jdbc.core.JdbcTemplate; import org.springframework.stereotype.Component; import org.springframework.transaction.annotation.Transactional; @Component public class BookingService { private final static Logger logger = LoggerFactory.getLogger(BookingService.class); private final JdbcTemplate jdbcTemplate; public BookingService(JdbcTemplate jdbcTemplate) { this.jdbcTemplate = jdbcTemplate; } @Transactional public void book(String... persons) { for (String person : persons) { logger.info("Booking " + person + " in a seat..."); jdbcTemplate.update("insert into BOOKINGS(FIRST_NAME) values (?)", person); } } public List<String> findAllBookings() { return jdbcTemplate.query("select FIRST_NAME from BOOKINGS", (rs, rowNum) -> rs.getString("FIRST_NAME")); } } ~~~ 該代碼具有自動裝配 `JdbcTemplate`，這是一個方便的模板類，它完成其余代碼所需的所有數據庫交互。你也有一個 `book`可以預定多人的方法。它遍歷人員列表，并針對每個人員將該人員插入到 `BOOKINGS` 通過使用 `JdbcTemplate`。該方法被標記為 `@Transactional`，這意味著任何失敗都會導致整個操作回滾到其先前的狀態并重新引發原始異常。這意味著沒有人被添加到 `BOOKINGS` 如果添加一個人失敗。你也有一個 `findAllBookings`查詢數據庫的方法。從數據庫中提取的每一行都將轉換為 `String`，并且所有行都組裝成一個 `List`. ## 建立一個應用程序 Spring Initializr提供了一個應用程序類。在這種情況下，您無需修改??此應用程序類。以下清單（來自 `src/main/java/com/example/managingtransactions/ManagingTransactionsApplication.java`）顯示應用程序類 ~~~ package com.example.managingtransactions; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication public class ManagingTransactionsApplication { public static void main(String[] args) { SpringApplication.run(ManagingTransactionsApplication.class, args); } } ~~~ `@SpringBootApplication` 是一個方便注釋，它添加了以下所有內容： * `@Configuration`：將類標記為應用程序上下文的Bean定義的源。 * `@EnableAutoConfiguration`：告訴Spring Boot根據類路徑設置，其他bean和各種屬性設置開始添加bean。例如，如果 `spring-webmvc` 在類路徑上，此注釋將應用程序標記為Web應用程序并激活關鍵行為，例如設置 `DispatcherServlet`. * `@ComponentScan`：告訴Spring在服務器中尋找其他組件，配置和服務 `com/example` 包，讓它找到控制器。這 `main()` 方法使用Spring Boot的 `SpringApplication.run()`啟動應用程序的方法。您是否注意到沒有一行XML？沒有 `web.xml`文件。該Web應用程序是100％純Java，因此您無需處理任何管道或基礎結構。您的應用程序實際上具有零配置。 Spring Boot檢測 `spring-jdbc` 和 `h2` 在類路徑上并自動創建一個 `DataSource` 和一個 `JdbcTemplate`為你。由于此基礎結構現已可用，并且您沒有專用的配置，因此 `DataSourceTransactionManager`也為您創建。這是攔截帶有注釋的方法的組件 `@Transactional` （例如， `book` 方法開啟 `BookingService`）。這 `BookingService` 通過類路徑掃描檢測到。本指南中演示的另一個Spring Boot功能是 [在啟動時初始化架構的功能](https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#howto-initialize-a-database-using-spring-jdbc) 。以下文件（來自src / main / resources / schema.sql）定義了數據庫模式： ~~~ drop table BOOKINGS if exists; create table BOOKINGS(ID serial, FIRST_NAME varchar(5) NOT NULL); ~~~ 還有一個 [`CommandLineRunner`](https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-features-command-line-runner) 注入 `BookingService`并展示各種交易用例。以下清單（來自 `src/main/java/com/example/managingtransactions/AppRunner.java`）顯示了命令行運行器： ~~~ package com.example.managingtransactions; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.boot.CommandLineRunner; import org.springframework.stereotype.Component; import org.springframework.util.Assert; @Component class AppRunner implements CommandLineRunner { private final static Logger logger = LoggerFactory.getLogger(AppRunner.class); private final BookingService bookingService; public AppRunner(BookingService bookingService) { this.bookingService = bookingService; } @Override public void run(String... args) throws Exception { bookingService.book("Alice", "Bob", "Carol"); Assert.isTrue(bookingService.findAllBookings().size() == 3, "First booking should work with no problem"); logger.info("Alice, Bob and Carol have been booked"); try { bookingService.book("Chris", "Samuel"); } catch (RuntimeException e) { logger.info("v--- The following exception is expect because 'Samuel' is too " + "big for the DB ---v"); logger.error(e.getMessage()); } for (String person : bookingService.findAllBookings()) { logger.info("So far, " + person + " is booked."); } logger.info("You shouldn't see Chris or Samuel. Samuel violated DB constraints, " + "and Chris was rolled back in the same TX"); Assert.isTrue(bookingService.findAllBookings().size() == 3, "'Samuel' should have triggered a rollback"); try { bookingService.book("Buddy", null); } catch (RuntimeException e) { logger.info("v--- The following exception is expect because null is not " + "valid for the DB ---v"); logger.error(e.getMessage()); } for (String person : bookingService.findAllBookings()) { logger.info("So far, " + person + " is booked."); } logger.info("You shouldn't see Buddy or null. null violated DB constraints, and " + "Buddy was rolled back in the same TX"); Assert.isTrue(bookingService.findAllBookings().size() == 3, "'null' should have triggered a rollback"); } } ~~~ 您可以使用Gradle或Maven從命令行運行該應用程序。您還可以構建一個包含所有必需的依賴項，類和資源的可執行JAR文件，然后運行該文件。生成可執行jar使得在整個開發生命周期中，跨不同環境等等的情況下，都可以輕松地將服務作為應用程序進行發布，版本控制和部署。如果您使用Gradle，則可以通過使用以下命令運行該應用程序 `./gradlew bootRun`。或者，您可以通過使用以下命令構建JAR文件： `./gradlew build` 然后運行JAR文件，如下所示： ~~~ java -jar build/libs/gs-managing-transactions-0.1.0.jar ~~~ 如果您使用Maven，則可以通過使用以下命令運行該應用程序 `./mvnw spring-boot:run`。或者，您可以使用以下命令構建JAR文件： `./mvnw clean package` 然后運行JAR文件，如下所示： ~~~ java -jar target/gs-managing-transactions-0.1.0.jar ~~~ 此處描述的步驟將創建可運行的JAR。您還可以構建經典的WAR文件。您應該看到以下輸出： ~~~ 2019-09-19 14:05:25.111 INFO 51911 --- [ main] c.e.m.ManagingTransactionsApplication : Starting ManagingTransactionsApplication on Jays-MBP with PID 51911 (/Users/j/projects/guides/gs-managing-transactions/complete/target/classes started by j in /Users/j/projects/guides/gs-managing-transactions/complete) 2019-09-19 14:05:25.114 INFO 51911 --- [ main] c.e.m.ManagingTransactionsApplication : No active profile set, falling back to default profiles: default 2019-09-19 14:05:25.421 INFO 51911 --- [ main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data repositories in DEFAULT mode. 2019-09-19 14:05:25.438 INFO 51911 --- [ main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 13ms. Found 0 repository interfaces. 2019-09-19 14:05:25.678 INFO 51911 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting... 2019-09-19 14:05:25.833 INFO 51911 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Start completed. 2019-09-19 14:05:26.158 INFO 51911 --- [ main] c.e.m.ManagingTransactionsApplication : Started ManagingTransactionsApplication in 1.303 seconds (JVM running for 3.544) 2019-09-19 14:05:26.170 INFO 51911 --- [ main] c.e.managingtransactions.BookingService : Booking Alice in a seat... 2019-09-19 14:05:26.181 INFO 51911 --- [ main] c.e.managingtransactions.BookingService : Booking Bob in a seat... 2019-09-19 14:05:26.181 INFO 51911 --- [ main] c.e.managingtransactions.BookingService : Booking Carol in a seat... 2019-09-19 14:05:26.195 INFO 51911 --- [ main] c.e.managingtransactions.AppRunner : Alice, Bob and Carol have been booked 2019-09-19 14:05:26.196 INFO 51911 --- [ main] c.e.managingtransactions.BookingService : Booking Chris in a seat... 2019-09-19 14:05:26.196 INFO 51911 --- [ main] c.e.managingtransactions.BookingService : Booking Samuel in a seat... 2019-09-19 14:05:26.271 INFO 51911 --- [ main] c.e.managingtransactions.AppRunner : v--- The following exception is expect because 'Samuel' is too big for the DB ---v 2019-09-19 14:05:26.271 ERROR 51911 --- [ main] c.e.managingtransactions.AppRunner : PreparedStatementCallback; SQL [insert into BOOKINGS(FIRST_NAME) values (?)]; Value too long for column """FIRST_NAME"" VARCHAR(5) NOT NULL": "'Samuel' (6)"; SQL statement: insert into BOOKINGS(FIRST_NAME) values (?) [22001-199]; nested exception is org.h2.jdbc.JdbcSQLDataException: Value too long for column """FIRST_NAME"" VARCHAR(5) NOT NULL": "'Samuel' (6)"; SQL statement: insert into BOOKINGS(FIRST_NAME) values (?) [22001-199] 2019-09-19 14:05:26.271 INFO 51911 --- [ main] c.e.managingtransactions.AppRunner : So far, Alice is booked. 2019-09-19 14:05:26.271 INFO 51911 --- [ main] c.e.managingtransactions.AppRunner : So far, Bob is booked. 2019-09-19 14:05:26.271 INFO 51911 --- [ main] c.e.managingtransactions.AppRunner : So far, Carol is booked. 2019-09-19 14:05:26.271 INFO 51911 --- [ main] c.e.managingtransactions.AppRunner : You shouldn't see Chris or Samuel. Samuel violated DB constraints, and Chris was rolled back in the same TX 2019-09-19 14:05:26.272 INFO 51911 --- [ main] c.e.managingtransactions.BookingService : Booking Buddy in a seat... 2019-09-19 14:05:26.272 INFO 51911 --- [ main] c.e.managingtransactions.BookingService : Booking null in a seat... 2019-09-19 14:05:26.273 INFO 51911 --- [ main] c.e.managingtransactions.AppRunner : v--- The following exception is expect because null is not valid for the DB ---v 2019-09-19 14:05:26.273 ERROR 51911 --- [ main] c.e.managingtransactions.AppRunner : PreparedStatementCallback; SQL [insert into BOOKINGS(FIRST_NAME) values (?)]; NULL not allowed for column "FIRST_NAME"; SQL statement: insert into BOOKINGS(FIRST_NAME) values (?) [23502-199]; nested exception is org.h2.jdbc.JdbcSQLIntegrityConstraintViolationException: NULL not allowed for column "FIRST_NAME"; SQL statement: insert into BOOKINGS(FIRST_NAME) values (?) [23502-199] 2019-09-19 14:05:26.273 INFO 51911 --- [ main] c.e.managingtransactions.AppRunner : So far, Alice is booked. 2019-09-19 14:05:26.273 INFO 51911 --- [ main] c.e.managingtransactions.AppRunner : So far, Bob is booked. 2019-09-19 14:05:26.273 INFO 51911 --- [ main] c.e.managingtransactions.AppRunner : So far, Carol is booked. 2019-09-19 14:05:26.273 INFO 51911 --- [ main] c.e.managingtransactions.AppRunner : You shouldn't see Buddy or null. null violated DB constraints, and Buddy was rolled back in the same TX ~~~ 這 `BOOKINGS` 該表對兩個約束 `first_name` 柱子： * 名稱不能超過五個字符。 * 名稱不能為空。插入的前三個名稱是 `Alice`, `Bob`，和 `Carol`。該應用程序斷言三個人已添加到該表。如果那不起作用，則該應用程序可能會提早退出。接下來，完成另一項預訂 `Chris` 和 `Samuel`。塞繆爾（Samuel）的名稱故意過長，從而導致插入錯誤。交易行為規定 `Chris` 和 `Samuel`（即該事務中的所有值）應回滾。因此，該斷言表明了該表中應該仍然只有三個人。最后， `Buddy` 和 `null`被預訂。如輸出所示， `null` 也會導致回滾，從而保留了相同的三個人。 ## 概括恭喜你！您剛剛使用Spring開發了一個簡單的JDBC應用程序，該應用程序包裝了非介入式事務。