Spring Boot CRUD-Beispiel mit MySQL

In diesem Beispiel erfahren Sie, wie Sie Spring Boot Data JPA verwenden, um Operationen zum Einfügen, Aktualisieren, Löschen und Auswählen von Datenbanktabellen in MySQL-Datenbanktabellen zu implementieren. Mit Spring Boot Data JPA wurde der Datenbanktabellen-Operationsbefehl in eine Methode verpackt, Sie müssen nur eine Java-Schnittstelle erstellen, die die grundlegende Spring Boot Data JPA-Repository-Schnittstelle erweitert (z. B. CrudRepository ), dann müssen Sie nur die Datenbanktabellen-Operationsmethode definieren (z. B. findBy , deleteBy, usw.) in der benutzerdefinierten Repository-Schnittstelle, und der Methodenname muss speziellen Benennungsregeln folgen. Sie müssen keine SQL-Befehle in der Repository-Schnittstelle schreiben.

1. MySQL-Datenbanktabelle erstellen.

1. Erstellen Sie eine MySQL-Datenbank mit dem Namen dev2qa_example . Die Standardsortierung der Datenbank sollte utf8 – utf8_bin sein .

   CREATE SCHEMA `dev2qa_example` DEFAULT CHARACTER SET utf8 COLLATE utf8_bin ;

2. Erstellen Sie eine Tabelle user_account im obigen dev2qa_example Datenbank mit der folgenden SQL-Anweisung. Die ID Spalte sollte AI sein ( Inkrement automatisieren ), andernfalls wird ein Fehler Spring Boot JPA Table 'dbname.hibernate_sequence' Doesn't Exist ausgegeben.

   CREATE TABLE `dev2qa_example`.`user_account` (
     `id` INT NOT NULL AUTO_INCREMENT,
     `user_name` VARCHAR(100) NULL,
     `password` VARCHAR(100) NULL,
     `email` VARCHAR(100) NULL,
     PRIMARY KEY (`id`))
   ENGINE = InnoDB
   DEFAULT CHARACTER SET = utf8
   COLLATE = utf8_bin;
   

2. Spring Boot-Projekt erstellen.

1. Starten Sie die Spring Tool Suite, klicken Sie auf Datei –> Neu –> Spring Starter-Projekt Menüpunkt zum Öffnen unter New Spring Starter Project Magier. Geben Sie verwandte Projektinformationen wie unten ein. Und klicken Sie auf die Schaltfläche Weiter.
   
2. Fügen Sie JPA hinzu , MySQL, und Web Bibliotheken im Assistenten für Abhängigkeiten. Und klicken Sie auf Fertig stellen Schaltfläche, um die Projektinitialisierung abzuschließen.
   

3. Spring Boot JPA CRUD-Beispielprojektdateien.

Unten sind die Quelldateien in diesem Projekt. Wir werden sie nach und nach vorstellen.

C:\WORKSPACE\WORK\DEV2QA.COM-EXAMPLE-CODE\SPRINGBOOT\SPRINGBOOTCRUDMYSQL
│   pom.xml
└───src
    ├───main
    │   ├───java
    │   │   └───com
    │   │       └───dev2qa
    │   │           └───example
    │   │               │   SpringBootCrudMySqlApplication.java
    │   │               │
    │   │               ├───controller
    │   │               │       UserAccountController.java
    │   │               │
    │   │               ├───entity
    │   │               │       UserAccount.java
    │   │               │
    │   │               └───repository
    │   │                       UserAccountRepository.java
    │   │
    │   └───resources
    │           application.properties
    │
    └───test
        └───java
            └───com
                └───dev2qa
                        SpringBootCrudMySqlApplicationTests.java

3.1 SpringBootCrudMySqlApplication.java

Dies ist das Spring-Boot-Beispiel, das mit der Java-Klasse beginnt. Es wird zuerst in der Spring Boot-Anwendung geladen und ausgeführt.

package com.dev2qa.example;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

//@SpringBootApplication
@Configuration
@ComponentScan(basePackages = { "com.dev2qa.example" })
@EnableAutoConfiguration
public class SpringBootCrudMySqlApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringBootCrudMySqlApplication.class, args);
    }
}

3.2 UserAccountController.java

Dies ist die Spring-MVC-Controller-Java-Klasse, die die Benutzeranforderungs-URL der Verarbeitungsmethode zuordnet.

package com.dev2qa.example.controller;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;

import com.dev2qa.example.entity.UserAccount;
import com.dev2qa.example.repository.UserAccountRepository;

@Controller
@RequestMapping(path = "/userAccount")
public class UserAccountController {

    @Autowired
    UserAccountRepository userAccountRepository;

    /*
     * Mapping url exmaple:
     * https://localhost:8080/userAccount/add?userName=Jerry&password=888888&email=
     * jexample@sqldat.com
     * https://localhost:8080/userAccount/add?userName=Richard&password=888888&email=
     * example@sqldat.com
     */
    @GetMapping(path = "/add")
    @ResponseBody
    public String addUser(@RequestParam String userName, @RequestParam String password, @RequestParam String email) {

        UserAccount userAccount = new UserAccount();
        userAccount.setUsername(userName);
        userAccount.setPassword(password);
        userAccount.setEmail(email);

        userAccountRepository.save(userAccount);

        String ret = "User account has been added, user name = " + userName + ", password = " + password + ", email = "
                + email;

        return ret;

    }

    /*
     * Mapping url exmaple: https://localhost:8080/userAccount/findAll
     */
    @GetMapping(path = "/findAll")
    @ResponseBody
    public String findAllUser() {

        StringBuffer retBuf = new StringBuffer();

        List<UserAccount> userAccountList = (List<UserAccount>) userAccountRepository.findAll();

        if (userAccountList != null) {
            for (UserAccount userAccount : userAccountList) {
                retBuf.append("user name = ");
                retBuf.append(userAccount.getUsername());
                retBuf.append(", password = ");
                retBuf.append(userAccount.getPassword());
                retBuf.append(", email = ");
                retBuf.append(userAccount.getEmail());
                retBuf.append("\r\n");
            }
        }

        if (retBuf.length() == 0) {
            retBuf.append("No record find.");
        } else {
            retBuf.insert(0, "<pre>");
            retBuf.append("</pre>");
        }

        return retBuf.toString();
    }

    /*
     * Mapping url exmaple:
     * https://localhost:8080/userAccount/findByName?userName=Jerry
     */
    @GetMapping(path = "/findByName")
    @ResponseBody
    public String findByName(@RequestParam String userName) {

        StringBuffer retBuf = new StringBuffer();

        List<UserAccount> userAccountList = (List<UserAccount>) userAccountRepository.findByUsername(userName);

        if (userAccountList != null) {
            for (UserAccount userAccount : userAccountList) {
                retBuf.append("user name = ");
                retBuf.append(userAccount.getUsername());
                retBuf.append(", password = ");
                retBuf.append(userAccount.getPassword());
                retBuf.append(", email = ");
                retBuf.append(userAccount.getEmail());
                retBuf.append("\r\n");
            }
        }

        if (retBuf.length() == 0) {
            retBuf.append("No record find.");
        }

        return retBuf.toString();
    }

    /*
     * Mapping url exmaple:
     * https://localhost:8080/userAccount/findByNameAndPassword?userName=Jerry&
     * password=888888
     */
    @GetMapping(path = "/findByNameAndPassword")
    @ResponseBody
    public String findByNameAndPassword(@RequestParam String userName, @RequestParam String password) {

        StringBuffer retBuf = new StringBuffer();

        List<UserAccount> userAccountList = (List<UserAccount>) userAccountRepository
                .findByUsernameAndPassword(userName, password);

        if (userAccountList != null) {
            for (UserAccount userAccount : userAccountList) {
                retBuf.append("user name = ");
                retBuf.append(userAccount.getUsername());
                retBuf.append(", password = ");
                retBuf.append(userAccount.getPassword());
                retBuf.append(", email = ");
                retBuf.append(userAccount.getEmail());
                retBuf.append("<br/>");
            }
        }

        if (retBuf.length() == 0) {
            retBuf.append("No record find.");
        }

        return retBuf.toString();
    }

    /*
     * Mapping url exmaple:
     * https://localhost:8080/userAccount/updateUser?userName=Jerry&password=hello&
     * example@sqldat.com
     */
    @GetMapping(path = "/updateUser")
    @ResponseBody
    public String updateUser(@RequestParam String userName, @RequestParam String password, @RequestParam String email) {

        StringBuffer retBuf = new StringBuffer();

        List<UserAccount> userAccountList = userAccountRepository.findByUsername(userName);

        if (userAccountList != null) {
            for (UserAccount userAccount : userAccountList) {
                userAccount.setUsername(userName);
                userAccount.setPassword(password);
                userAccount.setEmail(email);
                userAccountRepository.save(userAccount);
            }
        }

        retBuf.append("User data update successfully.");

        return retBuf.toString();
    }

    /*
     * Mapping url exmaple:
     * https://localhost:8080/userAccount/deleteByUserName?userName=Richard
     */
    @GetMapping(path = "/deleteByUserName")
    @ResponseBody
    public String deleteByUserName(@RequestParam String userName) {

        StringBuffer retBuf = new StringBuffer();

        userAccountRepository.deleteByUsername(userName);

        retBuf.append("User data has been deleted successfully.");

        return retBuf.toString();
    }

    /*
     * Mapping url exmaple:
     * https://localhost:8080/userAccount/deleteByUserNameAndPassword?userName=
     * Richard&password=888888
     */
    @GetMapping(path = "/deleteByUserNameAndPassword")
    @ResponseBody
    public String deleteByUserNameAndPassword(@RequestParam String userName, @RequestParam String password) {

        StringBuffer retBuf = new StringBuffer();

        userAccountRepository.deleteByUsernameAndPassword(userName, password);

        retBuf.append("User data has been deleted successfully.");

        return retBuf.toString();
    }

}

package com.dev2qa.example.entity;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

/* Map this entity class to user_account table. */
@Entity(name = "user_account")
public class UserAccount {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @javax.persistence.Column(name = "user_name")
    private String username;

    private String password;

    private String email;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

}

package com.dev2qa.example.repository;

import java.util.List;

import org.springframework.data.repository.CrudRepository;
import org.springframework.transaction.annotation.Transactional;

import com.dev2qa.example.entity.UserAccount;

public interface UserAccountRepository extends CrudRepository<UserAccount, Long> {

    /*
     * Get user list by user name. Please note the format should be
     * findBy<column_name>.
     */
    List<UserAccount> findByUsername(String username);

    /*
     * Get user list by user name and password. Please note the format should be
     * findBy<column_name_1>And<column_name_2>.
     */
    List<UserAccount> findByUsernameAndPassword(String username, String password);

    @Transactional
    void deleteByUsernameAndPassword(String username, String password);

    @Transactional
    void deleteByUsername(String username);

}

# MySQL jdbc connection url.
spring.datasource.url=jdbc:mysql://localhost:3306/dev2qa_example
# MySQL jdbc driver class name.
spring.datasource.driverClassName=com.mysql.cj.jdbc.Driver
# MySQL database username and password
spring.datasource.username=root
spring.datasource.password=root

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="https://maven.apache.org/POM/4.0.0" xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="https://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.example</groupId>
    <artifactId>SpringBootCRUDMySQL</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>SpringBootCRUDMySQL</name>
    <description>Spring boot access mysql with crud operation.</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.0.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</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>