玩转spring boot——AOP与表单验证

2022-10-01 18:09:59

前言

AOP在大多数的情况下的应用场景是：日志和验证。至于AOP的理论知识我就不做赘述。而AOP的通知类型有好几种，今天的例子我只选一个有代表意义的“环绕通知”来演示。

一、AOP入门

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>spring07</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>spring07</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-aop</artifactId>

        </dependency>

        <dependency>

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

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

        </dependency>

        <dependency>

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

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

            <optional>true</optional>

        </dependency>

    </dependencies>

    <build>

        <plugins>

            <plugin>

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

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

            </plugin>

        </plugins>

    </build>

</project>

pom.xml

修改入口类文件“App.java”：

package com.github.carter659.spring07;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication

public class App {

    public static void main(String[] args) {

        SpringApplication.run(App.class, args);

    }

}

App.java

控制器MainController：

package com.github.carter659.spring07;

import java.util.HashMap;

import java.util.Map;

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.ResponseBody;

@Controller

public class MainController {

    @GetMapping("/")

    public String index() {

        return "index";

    }

    @PostMapping("/save")

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

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

        map.put("msg", "ok");

        return map;

    }

}

我们拦截控制器中的返回Map的方法。

新建切面类文件“AopAspect.java”：

package com.github.carter659.spring07;

import java.util.HashMap;

import java.util.Map;

import org.aspectj.lang.ProceedingJoinPoint;

import org.aspectj.lang.annotation.Around;

import org.aspectj.lang.annotation.Aspect;

import org.springframework.stereotype.Component;

@Component

@Aspect

public class AopAspect {

    @Around("execution (java.util.Map com.github.carter659.spring07.MainController.*( .. ) ) ")

    public Object invoke(ProceedingJoinPoint point) {

        Map<String, Object> map = null;

        try {

            Object[] args = point.getArgs();

            Object val = point.proceed(args);

            map = (Map<String, Object>) val;

        } catch (Throwable e) {

            e.printStackTrace();

            map = new HashMap<>();

            map.put("msg", e.toString());

        }

        map.put("aop", "拦截了一个请求");

        return map;

    }

}

如果能拦截到MainController中的方法，则会在Map中put一对键值。

templates模板：

<!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AOP</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) {

        //保存

        $scope.save = function() {

            $http({

                url : '/save',

                method : 'POST'

            }).success(function(r) {

                $scope.result = JSON.stringify(r)

            });

        }

    });

    /*]]>*/

</script>

</head>

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

    <h1>玩转spring boot——结合AOP</h1>

    <h4>

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

    </h4>

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

    <br />

    <h3>调用结果：</h3>

    <p>{{result}}</p>

    <br />

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

</body>

</html>

index.html

运行效果：

点击调用按钮后：

二、表单验证

　　由于有了一节的AOP拦截，那么表单验证就完全可以实现了。但是，spring boot给我们提供了原生的表单验证实例。一些简单的验证，我建议实现spring boot自带的验证，因为它足够简单好用，而复杂的验证可以用AOP来实现。

参考：参考：https://spring.io/guides/gs/validating-form-input/

控制器：

package com.github.carter659.spring07;

import java.util.HashMap;

import java.util.Map;

import javax.validation.Valid;

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 {

    @GetMapping("/")

    public String index() {

        return "index";

    }

    @PostMapping("/save")

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

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

        map.put("msg", "ok");

        return map;

    }

    @PostMapping("/saveOrder")

    public @ResponseBody Map<String, Object> saveOrder(@RequestBody @Valid Order order) {

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

        map.put("msg", "ok");

        map.put("order", order);

        return map;

    }

}

MainController.java

在要验证的方法的参数中增加@Valid注解。

修改Order类：

package com.github.carter659.spring07;

import java.util.Date;

import javax.validation.constraints.Min;

import javax.validation.constraints.NotNull;

import javax.validation.constraints.Size;

/**

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

 *

 * @author 刘冬

 *

 */

public class Order {

    public String id;

    @NotNull

    @Size(min = 10, max = 20)

    public String no;

    @NotNull

    public Date date;

    @Min(100)

    @NotNull

    public Integer quantity;

    /**

     * 省略 get set

     */

}

增加这javax.validation.constraints包下的验证注解。

修改index.html：

<!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AOP与表单验证</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 = {

            no : 'no.1234567890',

            date : '2017-01-01',

            quantity : 100

        };

        $scope.errors = {

            no : '',

            date : '',

            quantity : ''

        };

        //保存

        $scope.save = function() {

            $http({

                url : '/save',

                method : 'POST'

            }).success(function(r) {

                $scope.result = JSON.stringify(r)

            });

        }

        $scope.saveOrder = function() {

            $http({

                url : '/saveOrder',

                method : 'POST',

                data : $scope.data

            }).success(function(r) {

                $scope.result = JSON.stringify(r)

            }).error(function(e) {

                $scope.result = JSON.stringify(e)

                $scope.errors.no = '';

                $scope.errors.date = '';

                $scope.errors.quantity = '';

                for ( var i in e.errors) {

                    var error = e.errors[i];

                    var field = $scope.errors[error.field];

                    if (field == undefined)

                        continue;

                    $scope.errors[error.field] = error.defaultMessage;

                }

            })

        }

    });

    /*]]>*/

</script>

</head>

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

    <h1>玩转spring boot——结合AOP与表单验证</h1>

    <h4>

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

    </h4>

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

    <br />

    <br />

    <input type="button" value="保存订单" ng-click="saveOrder()" />

    <br /> 订单信息：

    <br />

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

        <tr>

            <td>编号：</td>

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

            <td><font color="red" ng-show="errors.no">{{errors.no}}</font></td>

        </tr>

        <tr>

            <td>日期：</td>

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

            <td><font color="red" ng-show="errors.date">{{errors.date}}</font></td>

        </tr>

        <tr>

            <td>数量：</td>

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

            <td><font color="red" ng-show="errors.quantity">{{errors.quantity}}</font></td>

        </tr>

    </table>

    <br />

    <h3>调用结果：</h3>

    <p>{{result}}</p>

    <br />

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

</body>

</html>