玩转spring boot——结合JPA入门

2022-10-01 18:15:03

参考官方例子：https://spring.io/guides/gs/accessing-data-jpa/

接着上篇内容

一、小试牛刀

创建maven项目后，修改pom.xml文件

<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">

    <modelVersion>4.0.0</modelVersion>

    <groupId>com.github.carter659</groupId>

    <artifactId>spring05</artifactId>

    <version>0.0.1-SNAPSHOT</version>

    <packaging>jar</packaging>

    <parent>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-starter-parent</artifactId>

        <version>1.4.2.RELEASE</version>

    </parent>

    <name>spring05</name>

    <url>http://maven.apache.org</url>

    <properties>

        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>

        <java.version>1.8</java.version>

    </properties>

    <dependencies>

        <dependency>

            <groupId>org.springframework.boot</groupId>

            <artifactId>spring-boot-starter-web</artifactId>

        </dependency>

        <dependency>

            <groupId>org.springframework.boot</groupId>

            <artifactId>spring-boot-devtools</artifactId>

            <optional>true</optional>

        </dependency>

        <dependency>

            <groupId>org.springframework.boot</groupId>

            <artifactId>spring-boot-starter-thymeleaf</artifactId>

        </dependency>

        <dependency>

            <groupId>org.springframework.boot</groupId>

            <artifactId>spring-boot-starter-data-jpa</artifactId>

        </dependency>

        <dependency>

            <groupId>mysql</groupId>

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

        </dependency>

        <dependency>

            <groupId>commons-dbcp</groupId>

            <artifactId>commons-dbcp</artifactId>

        </dependency>

    </dependencies>

    <build>

        <plugins>

            <plugin>

                <groupId>org.springframework.boot</groupId>

                <artifactId>spring-boot-maven-plugin</artifactId>

            </plugin>

        </plugins>

    </build>

</project>

pom.xml

多引入了JPA的依赖：

<dependency>

            <groupId>org.springframework.boot</groupId>

            <artifactId>spring-boot-starter-data-jpa</artifactId>

</dependency>

src/main/resources/application.properties和src/main/resources/templates/index.html保持上篇不变：

spring.datasource.initialize=false

spring.datasource.url=jdbc:mysql://localhost:3306/demo

spring.datasource.username=root

spring.datasource.password=

spring.datasource.driver-class-name=com.mysql.jdbc.Driver

application.properties

<!DOCTYPE html>

<html xmlns:th="http://www.thymeleaf.org">

<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />

<title>玩转spring boot——结合JPA</title>

<script src="//cdn.bootcss.com/angular.js/1.5.6/angular.min.js"></script>

<script type="text/javascript">

    /*<![CDATA[*/

    var app = angular.module('app', []);

    app.controller('MainController', function($rootScope, $scope, $http) {

        $scope.data = {};

        $scope.rows = [];

        //添加

        $scope.add = function() {

            $scope.data = {

                no : 'No.1234567890',

                quantity : 100,

                'date' : '2016-12-30'

            };

        }

        //编辑

        $scope.edit = function(id) {

            for ( var i in $scope.rows) {

                var row = $scope.rows[i];

                if (id == row.id) {

                    $scope.data = row;

                    return;

                }

            }

        }

        //移除

        $scope.remove = function(id) {

            for ( var i in $scope.rows) {

                var row = $scope.rows[i];

                if (id == row.id) {

                    $scope.rows.splice(i, 1);

                    return;

                }

            }

        }

        //保存

        $scope.save = function() {

            $http({

                url : '/save',

                method : 'POST',

                data : $scope.data

            }).success(function(r) {

                //保存成功后更新数据

                $scope.get(r.id);

            });

        }

        //删除

        $scope.del = function(id) {

            $http({

                url : '/delete?id=' + id,

                method : 'POST',

            }).success(function(r) {

                //删除成功后移除数据

                $scope.remove(r.id);

            });

        }

        //获取数据

        $scope.get = function(id) {

            $http({

                url : '/get?id=' + id,

                method : 'POST',

            }).success(function(data) {

                for ( var i in $scope.rows) {

                    var row = $scope.rows[i];

                    if (data.id == row.id) {

                        row.no = data.no;

                        row.date = data.date;

                        row.quantity = data.quantity;

                        return;

                    }

                }

                $scope.rows.push(data);

            });

        }

        //初始化载入数据

        $http({

            url : '/findAll',

            method : 'POST'

        }).success(function(rows) {

            for ( var i in rows) {

                var row = rows[i];

                $scope.rows.push(row);

            }

        });

    });

    /*]]>*/

</script>

</head>

<body ng-app="app" ng-controller="MainController">

    <h1>玩转spring boot——结合JPA</h1>

    <h4>

        <a href="http://www.cnblogs.com/GoodHelper/">from 刘冬的博客</a>

    </h4>

    <input type="button" value="添加" ng-click="add()" />

    <input type="button" value="保存" ng-click="save()" />

    <br />

    <br />

    <h3>清单信息：</h3>

    <input id="id" type="hidden" ng-model="data.id" />

    <table cellspacing="1" style="background-color: #a0c6e5">

        <tr>

            <td>编号：</td>

            <td><input id="no" ng-model="data.no" /></td>

            <td>日期：</td>

            <td><input id="date" ng-model="data.date" /></td>

            <td>数量：</td>

            <td><input id="quantity" ng-model="data.quantity" /></td>

        </tr>

    </table>

    <br />

    <h3>清单列表：</h3>

    <table cellspacing="1" style="background-color: #a0c6e5">

        <tr

            style="text-align: center; COLOR: #0076C8; BACKGROUND-COLOR: #F4FAFF; font-weight: bold">

            <td>操作</td>

            <td>编号</td>

            <td>日期</td>

            <td>数量</td>

        </tr>

        <tr ng-repeat="row in rows" bgcolor='#F4FAFF'>

            <td><input ng-click="edit(row.id)" value="编辑" type="button" /><input

                ng-click="del(row.id)" value="删除" type="button" /></td>

            <td>{{row.no}}</td>

            <td>{{row.date}}</td>

            <td>{{row.quantity}}</td>

        </tr>

    </table>

    <br />

    <a href="http://www.cnblogs.com/GoodHelper/">点击访问原版博客</a>

</body>

</html>

index.html

修改上篇的“Order.java”类：

package com.github.carter659.spring05;

import java.util.Date;

import javax.persistence.Column;

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.Id;

import javax.persistence.Table;

import javax.persistence.Temporal;

import javax.persistence.TemporalType;

import org.hibernate.annotations.GenericGenerator;

/**

 * 博客出处：http://www.cnblogs.com/GoodHelper/

 *

 * @author 刘冬

 *

 */

@Entity

@Table(name = "t_order")

public class Order {

    @Id

    @GeneratedValue(generator = "uuid")

    @GenericGenerator(name = "uuid", strategy = "uuid2")

    @Column(name = "order_id", length = 36)

    public String id;

    @Column(name = "order_no", length = 50)

    public String no;

    @Temporal(TemporalType.DATE)

    @Column(name = "order_date")

    public Date date;

    @Column(name = "quantity")

    public int quantity;

    /**

     * 省略 get set

     */

}

新建“OrderRepository.java”文件

package com.github.carter659.spring05;

import org.springframework.data.jpa.repository.JpaRepository;

/**

 * 博客出处：http://www.cnblogs.com/GoodHelper/

 *

 * @author 刘冬

 *

 */

public interface OrderRepository extends JpaRepository<Order, String> {

}

这个类实现了JpaRepository<>接口，此接口附带常用的增删改查到方法。

修改上篇的控制器“MainController.java”文件

package com.github.carter659.spring05;

import java.util.HashMap;

import java.util.Map;

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.PostMapping;

import org.springframework.web.bind.annotation.RequestBody;

import org.springframework.web.bind.annotation.ResponseBody;

/**

 * 博客出处：http://www.cnblogs.com/GoodHelper/

 *

 * @author 刘冬

 *

 */

@Controller

public class MainController {

    @Autowired

    private OrderRepository orderRepository;

    @GetMapping("/")

    public String index() {

        return "index";

    }

    /**

     * 持久化

     *

     * @param entity

     * @return

     */

    @PostMapping("/save")

    public @ResponseBody Map<String, Object> save(@RequestBody Order entity) {

        Map<String, Object> result = new HashMap<>();

        entity = orderRepository.save(entity);

        result.put("id", entity.id);

        return result;

    }

    /**

     * 获取对象

     *

     * @param id

     * @return

     */

    @PostMapping("/get")

    public @ResponseBody Object get(String id) {

        return orderRepository.findOne(id);

    }

    /**

     * 获取全部

     *

     * @return

     */

    @PostMapping("/findAll")

    public @ResponseBody Object findAll() {

        return orderRepository.findAll();

    }

    /**

     * 删除

     *

     * @param id

     * @return

     */

    @PostMapping("/delete")

    public @ResponseBody Map<String, Object> delete(String id) {

        Map<String, Object> result = new HashMap<>();

        orderRepository.delete(id);

        result.put("id", id);

        return result;

    }

}

有人会问，在控制器中直接依赖注入了OrderRepository，并没有OrderRepository接口的实现类。在没有写实现类的情况下不报错吗？答案是并不报错，因为这些事儿都交给了JPA去做。那么为什么要用JPA，答案也只有2个字“方便”。我写这个系列博客的目的就是为了体现“方便”二字，使用最方便的技术来快速开发项目。

言归正传，App.java类保持不变：

package com.github.carter659.spring05;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

/**

 * 博客出处：http://www.cnblogs.com/GoodHelper/

 *

 * @author 刘冬

 *

 */

@SpringBootApplication

public class App {

    public static void main(String[] args) {

        SpringApplication.run(App.class, args);

    }

}

App.java

完整的项目结构如下图所示：

运行效果如下图，我就不做说明了：

二、高级查询

修改“OrderRepository.java”：

package com.github.carter659.spring05;

import java.util.Date;

import java.util.List;

import org.springframework.data.jpa.repository.JpaRepository;

/**

 * 博客出处：http://www.cnblogs.com/GoodHelper/

 *

 * @author 刘冬

 *

 */

public interface OrderRepository extends JpaRepository<Order, String> {

    /**

     * like查询

     *

     * @param no

     * @return

     */

    List<Order> findAllByNoLike(String no);

    /**

     * between查询

     *

     * @param startDate

     * @param endDate

     * @return

     */

    List<Order> findAllByDateBetween(Date startDate, Date endDate);

    /**

     * 小于查询

     *

     * @param quantity

     * @return

     */

    List<Order> findAllByQuantityLessThan(int quantity);

}

package com.github.carter659.spring05;

import java.text.SimpleDateFormat;

import java.util.Date;

import java.util.HashMap;

import java.util.Map;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.beans.propertyeditors.CustomDateEditor;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.WebDataBinder;

import org.springframework.web.bind.annotation.GetMapping;

import org.springframework.web.bind.annotation.InitBinder;

import org.springframework.web.bind.annotation.PostMapping;

import org.springframework.web.bind.annotation.RequestBody;

import org.springframework.web.bind.annotation.RequestParam;

import org.springframework.web.bind.annotation.ResponseBody;

/**

 * 博客出处：http://www.cnblogs.com/GoodHelper/

 *

 * @author 刘冬

 *

 */

@Controller

public class MainController {

    @Autowired

    private OrderRepository orderRepository;

    /**

     * 处理日期类型

     *

     * @param binder

     */

    @InitBinder

    public void initBinder(WebDataBinder binder) {

        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");

        dateFormat.setLenient(false);

        binder.registerCustomEditor(Date.class, new CustomDateEditor(dateFormat, true));

    }

    @GetMapping("/")

    public String index() {

        return "index";

    }

    /**

     * 持久化

     *

     * @param entity

     * @return

     */

    @PostMapping("/save")

    public @ResponseBody Map<String, Object> save(@RequestBody Order entity) {

        Map<String, Object> result = new HashMap<>();

        entity = orderRepository.save(entity);

        result.put("id", entity.id);

        return result;

    }

    /**

     * 获取对象

     *

     * @param id

     * @return

     */

    @PostMapping("/get")

    public @ResponseBody Object get(String id) {

        return orderRepository.findOne(id);

    }

    /**

     * 获取全部

     *

     * @return

     */

    @PostMapping("/findAll")

    public @ResponseBody Object findAll() {

        return orderRepository.findAll();

    }

    /**

     * 删除

     *

     * @param id

     * @return

     */

    @PostMapping("/delete")

    public @ResponseBody Map<String, Object> delete(String id) {

        Map<String, Object> result = new HashMap<>();

        orderRepository.delete(id);

        result.put("id", id);

        return result;

    }

    /**

     * like查询

     *

     * @return

     */

    @PostMapping("/findAllByNoLike")

    public @ResponseBody Object findAllByNoLike(@RequestParam String no) {

        return orderRepository.findAllByNoLike("%" + no + "%");

    }

    /**

     * between查询

     *

     * @return

     */

    @PostMapping("/findAllByDateBetween")

    public @ResponseBody Object findAllByDateBetween(@RequestParam Date startDate, @RequestParam Date endDate) {

        return orderRepository.findAllByDateBetween(startDate, endDate);

    }

    /**

     * 小于查询

     *

     * @return

     */

    @PostMapping("/findAllByQuantityLessThan")

    public @ResponseBody Object findAllByQuantityLessThan(int quantity) {

        return orderRepository.findAllByQuantityLessThan(quantity);

    }

}

<!DOCTYPE html>

<html xmlns:th="http://www.thymeleaf.org">

<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />

<title>玩转spring boot——结合JPA</title>

<script src="//cdn.bootcss.com/angular.js/1.5.6/angular.min.js"></script>

<script type="text/javascript">

    /*<![CDATA[*/

    var app = angular.module('app', []);

    app

            .controller(

                    'MainController',

                    function($rootScope, $scope, $http) {

                        $scope.data = {};

                        $scope.rows = [];

                        //添加

                        $scope.add = function() {

                            $scope.data = {

                                no : 'No.1234567890',

                                quantity : 100,

                                'date' : '2016-12-30'

                            };

                        }

                        //编辑

                        $scope.edit = function(id) {

                            for ( var i in $scope.rows) {

                                var row = $scope.rows[i];

                                if (id == row.id) {

                                    $scope.data = row;

                                    return;

                                }

                            }

                        }

                        //移除

                        $scope.remove = function(id) {

                            for ( var i in $scope.rows) {

                                var row = $scope.rows[i];

                                if (id == row.id) {

                                    $scope.rows.splice(i, 1);

                                    return;

                                }

                            }

                        }

                        //保存

                        $scope.save = function() {

                            $http({

                                url : '/save',

                                method : 'POST',

                                data : $scope.data

                            }).success(function(r) {

                                //保存成功后更新数据

                                $scope.get(r.id);

                            });

                        }

                        //删除

                        $scope.del = function(id) {

                            $http({

                                url : '/delete?id=' + id,

                                method : 'POST',

                            }).success(function(r) {

                                //删除成功后移除数据

                                $scope.remove(r.id);

                            });

                        }

                        //获取数据

                        $scope.get = function(id) {

                            $http({

                                url : '/get?id=' + id,

                                method : 'POST',

                            }).success(function(data) {

                                for ( var i in $scope.rows) {

                                    var row = $scope.rows[i];

                                    if (data.id == row.id) {

                                        row.no = data.no;

                                        row.date = data.date;

                                        row.quantity = data.quantity;

                                        return;

                                    }

                                }

                                $scope.rows.push(data);

                            });

                        }

                        //初始化载入数据

                        $http({

                            url : '/findAll',

                            method : 'POST'

                        }).success(function(rows) {

                            for ( var i in rows) {

                                var row = rows[i];

                                $scope.rows.push(row);

                            }

                        });

                        $scope.findAllByNoLike = function() {

                            $http(

                                    {

                                        url : '/findAllByNoLike',

                                        method : 'POST',

                                        headers : {

                                            'Content-Type' : 'application/x-www-form-urlencoded'

                                        },

                                        data : 'no=' + $scope.no

                                    }).success(function(rows) {

                                $scope.rows = rows;

                            });

                        };

                        $scope.findAllByDateBetween = function() {

                            $http(

                                    {

                                        url : '/findAllByDateBetween',

                                        method : 'POST',

                                        headers : {

                                            'Content-Type' : 'application/x-www-form-urlencoded'

                                        },

                                        data : 'startDate=' + $scope.startDate

                                                + '&endDate=' + $scope.endDate

                                    }).success(function(rows) {

                                $scope.rows = rows;

                            });

                        };

                        $scope.findAllByQuantityLessThan = function() {

                            $http(

                                    {

                                        url : '/findAllByQuantityLessThan',

                                        method : 'POST',

                                        headers : {

                                            'Content-Type' : 'application/x-www-form-urlencoded'

                                        },

                                        data : 'quantity=' + $scope.quantity

                                    }).success(function(rows) {

                                $scope.rows = rows;

                            });

                        };

                    });

    /*]]>*/

</script>

</head>

<body ng-app="app" ng-controller="MainController">

    <h1>玩转spring boot——结合JPA</h1>

    <h4>

        <a href="http://www.cnblogs.com/GoodHelper/">from 刘冬的博客</a>

    </h4>

    <input type="button" value="添加" ng-click="add()" />

    <input type="button" value="保存" ng-click="save()" />

    <br />

    <br />

    <h3>订单信息：</h3>

    <input type="hidden" ng-model="data.id" />

    <table cellspacing="1" style="background-color: #a0c6e5">

        <tr>

            <td>编号：</td>

            <td><input ng-model="data.no" /></td>

            <td>日期：</td>

            <td><input ng-model="data.date" /></td>

            <td>数量：</td>

            <td><input ng-model="data.quantity" /></td>

        </tr>

    </table>

    <br />

    <h3>查询条件：</h3>

    <table cellspacing="1" style="background-color: #a0c6e5">

        <tr>

            <td>编号：</td>

            <td><input ng-model="no" /></td>

            <td><input type="button" ng-click="findAllByNoLike()"

                value="like查询" /></td>

        </tr>

        <tr>

            <td>日期：</td>

            <td>从<input ng-model="startDate" />至<input ng-model="endDate" /></td>

            <td><input type="button" ng-click="findAllByDateBetween()"

                value="between查询" /></td>

        </tr>

        <tr>

            <td>数量：</td>

            <td><input ng-model="quantity" /></td>

            <td><input type="button" ng-click="findAllByQuantityLessThan()"

                value="小于查询" /></td>

        </tr>

    </table>

    <br />

    <h3>订单列表：</h3>

    <table cellspacing="1" style="background-color: #a0c6e5">

        <tr

            style="text-align: center; COLOR: #0076C8; BACKGROUND-COLOR: #F4FAFF; font-weight: bold">

            <td>操作</td>

            <td>编号</td>

            <td>日期</td>

            <td>数量</td>

        </tr>

        <tr ng-repeat="row in rows" bgcolor='#F4FAFF'>

            <td><input ng-click="edit(row.id)" value="编辑" type="button" /><input

                ng-click="del(row.id)" value="删除" type="button" /></td>

            <td>{{row.no}}</td>

            <td>{{row.date}}</td>

            <td>{{row.quantity}}</td>

        </tr>

    </table>

    <br />

    <a href="http://www.cnblogs.com/GoodHelper/">点击访问原版博客</a>

</body>

</html>