您的位置:首页 > 编程语言 > ASP

干货分享:ASP.NET CORE(C#)与Spring Boot MVC(JAVA)异曲同工的编程方式总结

2019-07-13 19:00 981 查看

目录

  • ASP.NET CORE VS Spring Boot 框架部署类比篇:

    我(梦在旅途,http://zuowj.cnblogs.com; http://www.zuowenjun.cn)最近发表的一篇文章《.NET CORE与Spring Boot编写控制台程序应有的优雅姿势》看到都上48小时阅读排行榜(当然之前发表的文章也有哦!),说明关注.NET CORE及Spring Boot的人很多,也是目前的主流方向,于是我便决定系统性的总结一下C# 与JAVA 、ASP.NET CORE 与 Spring Boot MVC,让更多的人了解它们,消除之前可能存在的对.NET或JAVA的误解。

    本文目的是通过全面简述C# 与JAVA 在基础语法以及ASP.NET CORE 与 Spring Boot MVC的在框架规范、部署、运行的异曲同工的实现方式,让大家更多的了解C#与JAVA,本文不会刻意说哪门语言好,我认为这是没有意义的,更多的是了解每种语言的特点、优点以及不同语言的共性,掌握编程内功(如:面向对象、DI、AOP、设计模式、算法),这样才能让自己更能适应社会及未来的变化。

    本文主要以示例代码为主,辅以简单文字说明,不会细讲每个语法点,只会体现不同的实现方式而矣,全文无废话,全是干货,慢慢欣赏吧。

    (注:本文内容是使用Markdown编辑器进行编辑完成!)

    C# VS JAVA 基础语法类比篇:

    一、匿名类

    C#(直接new{},在{}中直接定义只读公开属性或委托方法,无需预先定义任何接口或类)
    #region 1.匿名类
    var helloWord = new
    {
    CodeBy = "C#匿名类",
    Output = new Action<string, string>((name, codeBy) =>
    {
    System.Console.WriteLine($"Welcome:{name},Hello Word!  by {codeBy}");
    })
    };
    
    helloWord.Output("梦在旅途", helloWord.CodeBy);
    #endregion
    JAVA(需要先定义接口或类,然后 new 接口或类的构造函数{},{}内实现接口方法或重写父类接口)
    //1.匿名类
    IHelloWord helloWord=new IHelloWord() {
    @Override
    public void output(String name) {
    System.out.printf("Welcome:%s,Hello Word!  by %s\n",name,getCodeBy());
    }
    
    @Override
    public String getCodeBy() {
    return "JAVA匿名类";
    }
    };
    
    helloWord.output("梦在旅途");
    
    public interface IHelloWord {
    void output(String name);
    String getCodeBy();
    }

    二、类型初始化

    C#(IList类型(Dictionary、List)直接在new 类型{},在{}内直接使用{key,value}或{value}方式添加集合元素,其实是隐式调用了add方法)
    #region 2.类型初始化
    
    Dictionary<string, string> map = new Dictionary<string, string>
    {
    { "key1","value1" },//(隐式自动调用add方法)
    { "key2", "value2" },
    { "key3", "value3" }
    };
    
    foreach (var item in map)
    {
    System.Console.WriteLine($"key:{item.Key},value:{item.Value}");
    }
    
    List<string> list = new List<string>
    {
    "list-item1",//(隐式自动调用add方法)
    "list-item2",
    "list-item3"
    };
    
    foreach (string item in list)
    {
    System.Console.WriteLine(item);
    }
    
    String[] strArr = { "arr1", "arr2", "arr3" };
    foreach (string item in strArr)
    {
    System.Console.WriteLine(item);
    }
    
    Person person = new Person
    {
    Name = "梦在旅途",
    Age = 23,
    Sex = "男"
    };
    
    string json = JsonConvert.SerializeObject(person);
    System.Console.WriteLine("Person json:" + json);
    
    #endregion
    JAVA(new集合类型{},并在{}内再次使用{},即{{赋值 }},在双大括号内进行赋值操作,省略类名,这个特点有点类似VB及VB.NET的with语句,大家有兴趣可以了解一下,数组的初始化与C#相同,都可以直接在定义数组的时候在{}中给定元素)
    //2.类型初始化
    Map<String,String> map=new HashMap(){
    {
    put("key1","value1");
    put("key2","value2");
    put("key3","value3");
    }
    };
    
    for (Map.Entry<String, String> item:map.entrySet()) {
    System.out.printf("key:%1$s,value:%2$s\n",item.getKey(),item.getValue());
    }
    
    List<String> list=new ArrayList(){
    {
    add("list-item1");
    add("list-item2");
    add("list-item3");
    }
    };
    
    for (String item :list) {
    System.out.printf("%s\n",item);
    }
    
    String[] strArr={"arr1","arr2","arr3"};
    
    for (String item :strArr) {
    System.out.printf("%s\n",item);
    }
    
    Person person=new Person(){
    {
    setName("zwj");
    setAge(32);
    setSex("男");
    }
    };
    
    ObjectMapper jsonMapper=new ObjectMapper();
    String json= jsonMapper.writeValueAsString(person);
    System.out.println("Person json:" + json);

    三、委托(方法引用)

    C#(委托定义使用delegate关键字,后面就跟方法答名定义【不含方法体】,可委托普通方法,静态方法,有很多的现成的预定义委托类型,如:Action<T0...T16>,Func<T0...T16,TOut>各有16个重载)
    #region 3.委托
    delegate void HelloDelegate(string name);//定义委托类型(重点是方法签名)
    
    //常规普通自定义委托类型及委托相应的方法
    HelloWord helloWordObj = new HelloWord();
    
    HelloDelegate helloDelegate = helloWordObj.Output; //委托实例方法
    helloDelegate.Invoke("梦在旅途");// OR helloDelegate("梦在旅途");
    
    HelloDelegate helloDelegate2 = HelloWord.OutputForStatic; //委托类的静态方法
    helloDelegate2.Invoke("zuowenjun"); // OR helloDelegate2("zuowenjun");
    
    //使用通用的已封装好的委托类型(如:Func、Action)并实例化
    Func<int, int, int> multiplyFunc = new Func<int, int, int>(delegate (int a, int b)
    {
    return a * b;
    });
    
    int x = 12, y = 25;
    int multiplyResult = multiplyFunc.Invoke(x, y); //OR multiplyFunc(x,y);
    System.Console.WriteLine($"{x}乘以{y}等于:{multiplyResult}");
    
    Action<string> helloAction = new Action<string>(delegate (string name)
    {
    System.Console.WriteLine($"hello,{name},how are you!");
    System.Console.WriteLine("learning keep moving!");
    });
    helloAction.Invoke("www.zuowenjun.cn");
    
    #endregion
    JAVA(定义委托需要先定义委托类型【即:函数式接口,规则:接口+@FunctionalInterface+一个方法定义】,然后就可以普通方法,静态方法,有很多的现成的预定义委托类型【即:函数式接口】,如:BiFunction,Consumer等)
    //3.委托
    
    HelloWord helloWordObj = new HelloWord();
    
    HelloWordDelegate helloWordDelegate = helloWordObj::output;
    helloWordDelegate.invoke("梦在旅途");
    
    HelloWordDelegate helloWordDelegate2 = HelloWord::outputForStatic;
    helloWordDelegate2.invoke("zuowenjun");
    
    //使用已封装好的委托方法(JAVA这边称:函数式接口,有很多详见:https://www.runoob.com/java/java8-functional-interfaces.html)
    BiFunction<Integer, Integer, Integer> multiplyFunc = new BiFunction<Integer, Integer, Integer>() {
    @Override
    public Integer apply(Integer i, Integer i2) {
    return i * i2;
    }
    };
    
    int x = 12, y = 25;
    int multiplyResult = multiplyFunc.apply(x, y);
    System.out.printf("%d乘以%d等于:%d%n", x, y, multiplyResult);
    
    Consumer<String> helloAction=new Consumer<String>() {
    @Override
    public void accept(String s) {
    System.out.printf("hello,%s,how are you!%n",s);
    System.out.printf("learning keep moving!%n");
    }
    };
    helloAction.accept("www.zuowenjun.cn");
    
    @FunctionalInterface
    public interface HelloWordDelegate {
    void  invoke(String name);
    }
    
    public class HelloWord implements IHelloWord {
    
    @Override
    public void output(String name) {
    System.out.printf("Welcome:%s,Hello Word!  by %s\n",name,getCodeBy());
    }
    
    public  static void outputForStatic(String name){
    System.out.printf("Welcome:%s,Hello Word!  by JAVA static\n",name);
    }
    
    @Override
    public String getCodeBy() {
    return "JAVA";
    }
    }

    四、Lambda表达式

    C#(使用(入参)=>{方法处理体},与要传入或要实例化的委托方法签名相同即可)
    #region 4.Lambda
    
    Func<int, int, int> multiplyFunc2 = new Func<int, int, int>((a, b) => a * b);
    
    int x2 = 12, y2 = 25;
    int multiplyResult2 = multiplyFunc2.Invoke(x2, y2); //OR multiplyFunc(x,y);
    System.Console.WriteLine($"{x2}乘以{y2}等于:{multiplyResult2}");
    
    Action<string> helloAction2 = new Action<string>(name =>
    {
    System.Console.WriteLine($"hello,{name},how are you!");
    System.Console.WriteLine("learning keep moving!");
    });
    
    helloAction2.Invoke("www.zuowenjun.cn");
    
    int[] intArr = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
    intArr = intArr.Where(i => i >= 5).ToArray();
    foreach (int i in intArr)
    {
    System.Console.WriteLine($"int-{i}");
    }
    
    string msg = "测试外部变量被Lambda引用";
    Action testMsgAction = () =>
    {
    msg += "--改变内容";
    System.Console.WriteLine("Lambda方法体中的值:" + msg);
    };
    testMsgAction();
    System.Console.WriteLine("原始值:" + msg);
    
    #endregion
    JAVA(使用(入参)->{方法处理体},与要传入或要实例化的方法签名相同,且传入或实例化的类型必需是函数式接口【可以理解为自定义的委托类型】,注意与C#不同,Lambda方法体内不能引用外部非final的变量,与C# Lambda有本质不同
    //4.Lambda
    
    BiFunction<Integer, Integer, Integer> multiplyFunc = (i1, i2) -> i1 * i2;
    
    int x = 12, y = 25;
    int multiplyResult = multiplyFunc.apply(x, y);
    System.out.printf("%d乘以%d等于:%d%n", x, y, multiplyResult);
    
    Consumer<String> helloAction= s -> {
    System.out.printf("hello,%s,how are you!%n",s);
    System.out.printf("learning keep moving!%n");
    };
    helloAction.accept("www.zuowenjun.cn");
    
    int[] intArr = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
    intArr= Arrays.stream(intArr).filter(value -> value>=5).toArray();
    for (int n : intArr) {
    System.out.printf("int-%d%n",n);
    }

    五、泛型

    C#(真泛型,不同的泛型类型参数视为不同的类型,有泛型接口,泛型类,泛型方法,泛型委托,泛型约束:in表示逆变【泛型参数父类型转子类型,属于消费者,一般用于入参】,out 表示协变【泛型参数子类型转父类型】,只有委托、接口才支持可变性)
    #region 5.泛型
    
    //常用泛型集合类型
    List<int> intList = new List<int> { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
    
    List<long> longList = new List<long> { 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L };
    
    Dictionary<string, string> dic = new Dictionary<string, string> {
    { "k1","v1"},{ "k2","v2"},{ "k3","v3"}
    };
    
    //泛型方法
    var demo = new DemoGenericClass();
    //demo.DisplayResult("学习永无止境"); 错误,因为约束是值类型
    demo.DisplayResult(ConsoleColor.DarkGreen);
    
    List<YellowPerson> yellowPersonList = new List<YellowPerson> {
    new YellowPerson(){ Name="zzz",Age=11,Sex="G"},
    new YellowPerson(){ Name="xxx",Age=22,Sex="B"}
    };
    
    //协变(泛型参数子类转父类)
    //public interface IEnumerable<out T>
    IEnumerable<YellowPerson> yellowPersons = yellowPersonList;
    IEnumerable<Person> persons = yellowPersons;//协变(子类到父类的转变) ,泛型参数 out标记,一般用于出参,这个正确的
    
    // List<Person> personList = yellowPersonList; 因为List是类,而且泛型参数并没有标记out,不适用协变,故这样转换是错误的
    
    foreach (var p in persons)
    {
    System.Console.WriteLine($"item :【Name={p.Name},Age={p.Age},Sex={p.Sex},Color={p.Color}】");
    }
    
    //逆变(泛型参数父类转子类)
    Action<object, object> showPlusResultAction = (d1, d2) => Console.WriteLine($"{d1}+{d2}={d1.ToString() + d2.ToString()}");
    
    Action<string, string> showStrPlusResultAction = showPlusResultAction;//逆变(父类到子类的转变),泛型参数 in标记,一般用于入参
    
    showPlusResultAction(55, 66);
    showStrPlusResultAction("你好", "中国");
    
    ShowMsg<Person> showMsg = new ShowMsg<Person>((p) =>
    {
    System.Console.WriteLine($"ShowMsg :【Name={p.Name},Age={p.Age},Sex={p.Sex},Color={p.Color}】");
    });
    //ShowMsg<HelloWord> showMsg2 = new ShowMsg<HelloWord>(...); 这样是不行的,因为泛型约束为需继承自Person
    
    showMsg.Invoke(new Person() { Name = "zuowenjun", Age = 33, Sex = "B" });
    showMsg.Invoke(new YellowPerson() { Name = "zuowenjun2", Age = 33, Sex = "B" });
    
    //综合演示:入参逆变,出参协变
    Func<Person, Person, string> getDataFunc = (x, y) => x.Name + y.Name;
    Func<YellowPerson, YellowPerson, object> getDataFunc2 = getDataFunc;
    object dataResult = getDataFunc2(new YellowPerson() { Name = "张三", Age = 33, Sex = "G" }, new YellowPerson() { Name = "赵六", Age = 33, Sex = "B" });
    System.Console.WriteLine($"getDataFunc2:{dataResult}");
    
    List<int> a = new List<int>();
    List<String> b = new List<string>();
    bool isEqual = (a.GetType() == b.GetType());
    System.Console.WriteLine($"List<int> 与 List<String> {(isEqual ? "is" : "not")} Equal ");//结果是不相等
    
    #endregion
    
    //以上示例需要用到的类
    
    public class BaseClass
    {
    /// <summary>
    /// 必需是用virtual标记的方法(即:虚方法)或abstract标记的方法(即:抽象方法)子类才能使用override进行重写
    /// </summary>
    /// <param name="name"></param>
    public virtual void SayHello(string name)
    {
    System.Console.WriteLine($"{nameof(BaseClass)} Say:{name},hello!");
    }
    
    }
    
    public class DemoGenericClass : BaseClass, IDisposable
    {
    public void DisplayResult<T>(T arg) where T : struct
    {
    System.Console.WriteLine($"DemoGenericClass.DisplayResult:{arg}");
    }
    
    public void Dispose()
    {
    System.Console.WriteLine("DemoGenericClass Disposed");
    }
    
    public override void SayHello(string name)
    {
    base.SayHello(name);
    System.Console.WriteLine($"{nameof(DemoGenericClass)} Say:{name},hello again!");
    }
    }
    
    public class Person
    {
    public virtual Color Color { get; }
    public string Name { get; set; }
    
    public int Age { get; set; }
    
    public string Sex { get; set; }
    
    }
    
    public class BlackPerson : Person
    {
    public override Color Color => Color.Black;
    }
    
    public class YellowPerson : Person
    {
    public override Color Color => Color.Yellow;
    }
    
    public class WhitePerson : Person
    {
    public override Color Color => Color.White;
    }
    JAVA(伪泛型,编译后类型参数擦除,同一个泛型类型不同的泛型参数类型相同,有泛型接口,泛型类,泛型方法,泛型约束:super限定下边界,逆变,用于入参,属于消费者,extends限定上边界,协变,用于出参,属于生产者,还有?通匹符)
    //常用泛型集合
    List<Integer> intList = new ArrayList(){
    {
    add(1);
    add(2);
    add(3);
    add(4);
    add(5);
    }
    };
    
    Map<String,String> map=new HashMap(){
    {
    put("k1","v1");
    put("k2","v2");
    put("k3","v3");
    }
    };
    
    //泛型方法
    DemoGenericClass demo=new DemoGenericClass();
    demo.displayResult(new YellowPerson(){{
    setName("zwj");setSex("B");setAge(33);
    }});
    
    List<Integer> a=new ArrayList<>();
    List<String> b=new ArrayList<>();
    boolean isEqual =(a.getClass()==b.getClass());
    System.out.printf("List<Integer>与List<String> %s Equal %n",isEqual?"is":"not"); //结果是相等,都是同一个List类型,不能使用instanceof判断泛型类型实例
    
    //协变、逆变(详见说明:https://www.jianshu.com/p/2bf15c5265c5 ,意义与C#相同)
    List<? super Person> persons=new ArrayList<>(); //super:限定下边界,逆变,用于入参
    persons.add(new Person(){
    {
    setName("张三");
    setAge(25);
    setSex("B");
    }
    });
    
    persons.add(new YellowPerson(){
    {
    setName("赵六");
    setAge(18);
    setSex("G");
    }
    });
    
    List<? extends Person> result= (List<? extends Person>) persons;//extends:限定上边界,协变,用于出参
    for (Person p:result){
    System.out.printf("Person list item:%s %n",p.toString());
    }
    
    //以上示例需要用到的类
    public class DemoGenericClass implements AutoCloseable
    {
    @Override
    public void close() throws Exception {
    System.out.println("DemoGenericClass closed");
    }
    
    public <T extends Person> void displayResult(T arg) //泛型约束(泛型参数上边界,协变)
    {
    System.out.printf("DemoGenericClass.DisplayResult:%s %n",arg.toString());
    }
    }
    
    public class Person {
    private String name;
    private int age;
    private String sex;
    
    public String getName() {
    return name;
    }
    
    public void setName(String name) {
    this.name = name;
    }
    
    public int getAge() {
    return age;
    }
    
    public void setAge(int age) {
    this.age = age;
    }
    
    public String getSex() {
    return sex;
    }
    
    public void setSex(String sex) {
    this.sex = sex;
    }
    
    @Override
    public String toString() {
    return String.format("Person=[Name:%s,Age:%d,Sex:%s] %n", name, age, sex);
    }
    }
    
    class YellowPerson extends Person {
    
    @Override
    public String toString() {
    return "YellowPerson#toString-"+ super.toString();
    }
    }

    六、自动释放

    C#(采用using包裹,要实现自动释放必需实现AutoCloseable接口)
    using (var demo2 = new DemoGenericClass()) //DemoGenericClass实现IDisposable接口
    {
    demo2.DisplayResult(123456);
    }
    JAVA(采用try包裹,要实现自动释放必需实现IDisposable接口)
    try(DemoGenericClass demo=new DemoGenericClass()) {
    demo.displayResult(new YellowPerson(){
    {
    setName("zuowenjun");
    setAge(33);
    setSex("B");
    }
    });
    }

    七、重写(override)

    C#(必需是用virtual标记的方法(即:虚方法)或abstract标记的方法(即:抽象方法)子类才能使用override进行重写,重写后父类的方法将被子类取代,若需在子类中执行父类被重写的方法,应使用base关键字,若父类方法非虚方法或抽象方法但又想“重写”怎么办?则只能使用new覆盖方法,覆盖方法与重写方法的不同之处在于,在父类中仍可以正常执行父类的方法而不会执行子类的覆盖方法,覆盖方法的方法签名、访问修饰符均没有严格限制,即使不相同仍不会报错,但IDE会有提示,如需真正覆盖父类方法,则应按照重写的规范来,只是使用new来修饰覆盖方法,但覆盖方法与重写方法有本质不同,一般情况下更建议使用重写方法)

    C#所有类的普通方法默认是密封方法(类似JAVA的final方法),是不允许被重写,可以理解为默认是不开放的,需要开放重写的方法必需使用virtual标记为虚方法(虚方法至少是protected及以上的访问权限),若重写后不想被后续的子类再次重写,则可以标记为sealed,即:密封方法

    public class BaseClass
    {
    /// <summary>
    /// 必需是用virtual标记的方法(即:虚方法)或abstract标记的方法(即:抽象方法)子类才能使用override进行重写
    /// </summary>
    /// <param name="name"></param>
    public virtual void SayHello(string name)
    {
    System.Console.WriteLine($"{nameof(BaseClass)} Say:{name},hello!");
    }
    
    }
    
    public class DemoGenericClass : BaseClass
    {
    public override void SayHello(string name)
    {
    base.SayHello(name);
    System.Console.WriteLine($"{nameof(DemoGenericClass)} Say:{name},hello again!");
    }
    }
    JAVA(非private 且非 final 修饰的普通方法默认均可在子类中进行重写,重写要求基本与C#相同,只是无需强制Override关键字,但建议仍使用@Override注解,以便IDE进行重写规范检查,重写后父类的方法将被子类取代,若需在子类中执行父类被重写的方法,应使用super关键字)

    JAVA所有类的普通方法默认是虚方法,都是可以被重写,可以理解为默认是开放重写的,若不想被重写则应标记为final ,即:最终方法(C#中称密封方法)

    public  class BaseClass{
    public  void  testOutput(String msg){
    System.out.println("output Msg:" + msg);
    }
    }
    
    public class DemoGenericClass extends BaseClass
    {
    @Override
    public  void  testOutput(String msg){
    super.testOutput(msg);
    System.out.println("output again Msg:" + msg);
    }
    }

    ASP.NET CORE VS Spring Boot 框架部署类比篇:

    一、引用依赖(包)

    C#(编辑csproj文件,可以通过PackageReference引用包、ProjectReference引用同一个解决方案下的其它项目,Reference引用本地DLL组件,csproj除了引用包以外,还可以通过在PropertyGroup元素下配置相关的属性,比如TargetFramework指定SDK框架版本等)

    .NET项目的包是NuGet包,可以从nuget.org上查找浏览所需的包,项目中引用依赖包,除了在csproj文件中使用PackageReference添加编辑外(具体用法参见:项目文件中的包引用 (PackageReference))还可以使用package manager控制台使用包管理命令,如:

    Install-Package ExcelEasyUtil -Version 1.0.0
    ,或者直接使用.NET CLI命令行工具,如:
    dotnet add package ExcelEasyUtil --version 1.0.0

    .NET有包、元包、框架 之分,详细了解:包、元包和框架

    <!--包引用-->
    <ItemGroup>
    <PackageReference Include="Autofac.Extras.DynamicProxy" Version="4.5.0" />
    <PackageReference Include="Autofac" Version="4.9.2" />
    <PackageReference Include="Microsoft.AspNetCore.App" />
    <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="2.1.1" />
    <PackageReference Include="Autofac.Extensions.DependencyInjection" Version="4.4.0" />
    </ItemGroup>
    
    <!--同一解方案下的项目引用-->
    <ItemGroup>
    <ProjectReference Include="..\StandardClassLib2019\StandardClassLib2019.csproj"  />
    </ItemGroup>
    
    <!--本地组件直接引用-->
    <ItemGroup>
    <Reference Include="KYExpress.Common">
    <HintPath>xxxx\xxxx.dll</HintPath>
    <Private>true</Private>
    </Reference>
    </ItemGroup>
    JAVA(编辑POM 文件,通过dependencies.dependency来声明引入多个依赖,根据scope可以指定依赖的有效作用范围)
    <dependencies>
    <!--maven包依赖-->
    <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter</artifactId>
    </dependency>
    
    <!--本地JAR包依赖(scope=system,systemPath=jar包存放目录)-->
    <dependency>
    <groupId>cn.zuowenjun.boot.mybatis.plugin</groupId>
    <artifactId>cn.zuowenjun.boot.mybatis.plugin</artifactId>
    <version>1.0</version>
    <scope>system</scope>
    <systemPath>${basedir}/src/main/libs/xxxxx.jar</systemPath>
    </dependency>
    
    <!--同一父项目Module之间依赖,注意这个必需先创建基于POM的父项目,然后各子Moudle 的POM 的parent指向父项目-->
    <dependency>
    <groupId>cn.zuowenjun.springboot</groupId>
    <artifactId>springboot-demo1</artifactId>
    <version>1.0-SNAPSHOT</version>
    </dependency>
    </dependencies>

    JAVA POM 依赖继承两种方式

    通过parent继承,如下所示:(如下是非常典型的spring boot的parent继承),项目将继承spring-boot-starter-parent POM中的所有设置及依赖(如:properties、dependencies等)

    <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.6.RELEASE</version>
    </parent>

    通过dependencyManagement继承,如下所示:(这是依赖管理,dependencyManagement里只是声明依赖,并不实现引入,因此子项目可按需显式的声明所需的依赖项。如果不在子项目中声明依赖,则不会从父项目中继承依赖,只有在子项目中声明了依赖项,且没有指定具体版本,才会从父项目中继承依赖项,(写了版本号相当于覆盖),version和scope都读取自父pom)

    <dependencyManagement>
    <dependencies>
    <dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-dependencies</artifactId>
    <version>Greenwich.SR2</version>
    <type>pom</type>
    <scope>import</scope>
    </dependency>
    </dependencies>
    </dependencyManagement>

    二、依赖注入 DI (IOC容器)

    C#(一般在Startup文件中ConfigureServices方法中按需注册依赖,注册依赖可以指定生命周期如:AddTransient【瞬时,即:每次都创建新实例】、AddScoped【作用域范围内】、AddSingleton【单例,仅实例化一次】,具体效果可以参见:在 ASP.NET Core 依赖注入
    //1.使用ASP.NET CORE默认的DI框架,在Startup文件中ConfigureServices方法中按需注册依赖
    public void ConfigureServices(IServiceCollection services)
    {
    //采用ASP.NET CORE默认的IOC容器注册
    services.AddTransient<IOperationTransient, Operation>();
    services.AddScoped<IOperationScoped, Operation>();
    services.AddSingleton<IOperationSingleton, Operation>();
    services.AddSingleton<IOperationSingletonInstance>(new Operation(Guid.Empty));
    }
    
    //2.在Controller中就可以直接采用构造函数注入或指明从IOC容器中获得实例[FromServices]
    [ApiController]
    [Route("api/[controller]")]
    public class DemoController : Controller
    {
    private readonly OperationService operationService;
    
    public DemoController(OperationService operationService)
    {
    this.operationService = operationService;
    }
    
    [Route("optid")]
    public object Operation([FromServices]OperationService optSrv){
    //TODO:方法体中直接使用operationService 或 入参optSrv均可
    }
    }
    
    //如上所需接口及类定义
    
    public interface IOperation
    {
    Guid OperationId { get; }
    }
    
    public interface IOperationTransient : IOperation
    {
    }
    
    public interface IOperationScoped : IOperation
    {
    }
    
    public interface IOperationSingleton : IOperation
    {
    }
    
    public interface IOperationSingletonInstance : IOperation
    {
    }
    
    public class Operation : IOperationTransient,
    IOperationScoped,
    IOperationSingleton,
    IOperationSingletonInstance
    {
    public Operation() : this(Guid.NewGuid())
    {
    }
    
    public Operation(Guid id)
    {
    OperationId = id;
    }
    
    public Guid OperationId { get; private set; }
    }
    
    public class OperationService
    {
    public OperationService(
    IOperationTransient transientOperation,
    IOperationScoped scopedOperation,
    IOperationSingleton singletonOperation,
    IOperationSingletonInstance instanceOperation)
    {
    TransientOperation = transientOperation;
    ScopedOperation = scopedOperation;
    SingletonOperation = singletonOperation;
    SingletonInstanceOperation = instanceOperation;
    }
    
    public IOperationTransient TransientOperation { get; }
    public IOperationScoped ScopedOperation { get; }
    public IOperationSingleton SingletonOperation { get; }
    public IOperationSingletonInstance SingletonInstanceOperation { get; }
    
    }

    C#使用第三方IOC容器,如:autofac,由第三方IOC容器接管并实现DI,示例如下:(autofac支持更多、更灵活的依赖注入场景)

    public IServiceProvider ConfigureServices(IServiceCollection services)
    {
    //采用ASP.NET CORE默认的IOC容器注册
    services.AddTransient<IOperationTransient, Operation>();
    services.AddScoped<IOperationScoped, Operation>();
    services.AddSingleton<IOperationSingleton, Operation>();
    services.AddSingleton<IOperationSingletonInstance>(new Operation(Guid.Empty));
    
    services.AddTransient<OperationService, OperationService>();
    
    var containerBuilder = new ContainerBuilder();
    containerBuilder.Populate(services); //交由autofac IOC容器管理
    
    var container = containerBuilder.Build();
    return new AutofacServiceProvider(container);//使用utofac IOC容器
    }
    JAVA(可以使用xml来进行Bean的依赖注册,也可使用注解方式来进行依赖注册,目前在DI方面更多的是流行注解注册及注入,故这里也以注解依赖注册及注入为简要说明,更多有关注解依赖注册及注入以及XML的依赖注册及注入详细说明,可查阅我之前的文章:JAVA WEB快速入门之通过一个简单的Spring项目了解Spring的核心(AOP、IOC)

    注解依赖注册一般可以通过自定义一个spring统一注册配置类,如代码中所示BeansConfig,这种一般对于集中注册Bean或Bean之间有先后依赖,先后顺序时比较有效果;另一种是直接在Bean上使用@Component注解(或其它专用含义的注解,如:@Repository、@Service,这些注解本身也标记了@Component注解)

    //1. 在自定义的spring统一注册配置类中注册相关Bean
    @Configuration
    public class BeansConfig {
    
    @Bean
    @Scope("prototype") //singleton,request,session
    @Order(1) //注册顺序
    public DemoBean demoBean(){
    return new DemoBean();
    }
    
    @Bean("demo") //定义名称
    @Order(2)
    public  DemoInterface demoInterface(){
    return  new DemoImplBean(demoBean()); //构造函数注入
    }
    }
    
    //2.在Controller中就可以直接通过属性注入或构造函数注入获得实例,并在ACTION中使用这些实例对象
    @RestController
    public class DemoController {
    
    @Autowired
    private  DemoBean demoBean;
    
    @Autowired
    @Qualifier("demo")//指定从IOC中解析的bean注册名
    private  DemoInterface demoInterface;
    
    @Autowired
    private  DemoBean2 demoBean2;
    
    @RequestMapping(path = "/demo/msg",method = RequestMethod.GET,produces = "application/json;charset=utf-8")
    public Object testMsg(@RequestParam(value = "m",required = false) String m){
    //TODO:可直接使用:demoBean、demoInterface、demoBean2这些私有字段,它们通过属性注入
    return "test msg:" + m;
    }
    
    }
    
    //以下是如上所需的类及接口定义
    
    public class DemoBean {
    
    }
    
    public interface DemoInterface {
    void showMsg(String msg);
    }
    
    public class DemoImplBean implements  DemoInterface {
    
    private  DemoBean demoBean;
    
    public  DemoImplBean(DemoBean demoBean){
    this.demoBean=demoBean;
    }
    
    @Override
    public void showMsg(String msg) {
    System.out.println("show msg:" + msg);
    }
    }
    
    //通过标记Component,交由spring IOC自动扫描注册
    @Component
    public class DemoBean2 {
    
    }

    三、过滤器、拦截器 AOP

    C#(在ASP.NET CORE中实现AOP常见有三种方式:第一种:添加ACTION过滤器(仅适用于MVC);第二种:使用第三方的AOP切面拦截器(如下文的AopInterceptor,可拦截指定的任意位置的虚方法),第三种:在请求管道中添加中间件(仅适用MVC))
    public IServiceProvider ConfigureServices(IServiceCollection services)
    {
    services.AddMvc(opt => opt.Filters.Add<AopFilter>() //第一种:添加过滤器,实现ACTION执行前后记录耗时
    ).SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
    
    var containerBuilder = new ContainerBuilder();
    containerBuilder.Populate(services);
    
    containerBuilder.RegisterType<AopInterceptor>();
    containerBuilder.RegisterType<OperationService>().InterceptedBy(typeof(AopInterceptor)).EnableClassInterceptors(); //第二种:启用autofac的AOP拦截
    
    var container = containerBuilder.Build();
    return new AutofacServiceProvider(container);
    
    }
    
    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
    if (env.IsDevelopment())
    {
    app.UseDeveloperExceptionPage();
    }
    
    //第三种:使用一个自定义的中间件,实现AOP的效果
    app.Use(async (ctx, next) =>
    {
    //如果为示例逻辑
    if (!ctx.Request.Query.TryGetValue("token", out var tokenVal) || tokenVal != "zuowenjun")
    {
    await ctx.Response.WriteAsync("验证token失败,禁止访问!");
    return;
    }
    
    ctx.Request.EnableBuffering();//启动用buffer,以便可以重置Position
    var requestReader = new StreamReader(ctx.Request.Body);
    
    var requestContent = requestReader.ReadToEnd();
    ctx.Request.Body.Position = 0; //需要重置为流开头,否则将导致后续的Model Binding失效等各种问题
    
    var originalResponseStream = ctx.Response.Body;//记录原始请求
    using (var ms = new MemoryStream())
    {
    ctx.Response.Body = ms;//因原始请求为只写流,故此处用自定义的内存流来接收响应流数据
    
    var watch = Stopwatch.StartNew();
    await next.Invoke();
    watch.Stop();
    
    ms.Position = 0;
    var responseReader = new StreamReader(ms);
    var responseContent = responseReader.ReadToEnd();
    
    string logMsg = $"execedTime:{ watch.ElapsedMilliseconds.ToString() }ms,Request,{requestContent},Response: { responseContent}";
    Logger.LogInformation(logMsg);
    
    ms.Position = 0;//恢复流位置为开头
    
    await ms.CopyToAsync(originalResponseStream); //将当前的流合并到原始流中
    ctx.Response.Body = originalResponseStream; //恢复原始响应流
    };
    });
    
    app.UseMvc();
    
    }
    
    /// <summary>
    /// Filter仅针对接入层(MVC)有效,底层服务若需使用AOP,则必需使用特定的AOP框架
    /// </summary>
    public class AopFilter : IActionFilter
    {
    private readonly Stopwatch stopWatch = new Stopwatch();
    
    public void OnActionExecuting(ActionExecutingContext context)
    {
    //执行前逻辑
    stopWatch.Start();
    }
    
    public void OnActionExecuted(ActionExecutedContext context)
    {
    //执行后逻辑
    stopWatch.Stop();
    var returnResult = context.Result;
    if (returnResult is ObjectResult)
    {
    var objResult = (returnResult as ObjectResult);
    objResult.Value = new { Original = objResult.Value, ElapsedTime = stopWatch.ElapsedMilliseconds.ToString() + "ms" };
    }
    else if (returnResult is JsonResult)
    {
    var jsonResult = (returnResult as JsonResult);
    jsonResult.Value = new { Original = jsonResult.Value, ElapsedTime = stopWatch.ElapsedMilliseconds.ToString() + "ms" };
    }
    }
    
    }
    JAVA(可以通过自定义Filter、HandlerInterceptor、MethodInterceptor 、around AOP增强等方式实现AOP拦截处理)
    //最先执行,由servlet拦截请求(适用WEB)
    @WebFilter(filterName = "demoFilter",urlPatterns = "/*")
    class  DemoFilter implements Filter {
    
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    //初始化
    }
    
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
    //过滤处理
    }
    
    @Override
    public void destroy() {
    //销毁之前执行
    }
    }
    
    //其次执行,由spring MVC拦截请求(适用Spring MVC)
    @Component
    public class DemoHandlerInterceptor implements HandlerInterceptor  {
    //也可继承自HandlerInterceptorAdapter
    
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
    //执行前
    
    return false;
    }
    
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
    //执行后,生成视图之前执行
    }
    
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
    //在DispatcherServlet完全处理完请求之后被调用,可用于清理资源
    }
    }
    
    //最后执行,拦截方法
    @Component
    class DemoMethodInterceptor implements MethodInterceptor{
    
    @Override
    public Object invoke(MethodInvocation methodInvocation) throws Throwable {
    return null;
    }
    }
    
    //方法拦截的另一种形式
    @Component
    @Aspect
    class AutoAspectJInterceptor {
    
    @Around("execution (*..controller.*.*(..))")
    public Object around(ProceedingJoinPoint point) throws Throwable{
    //执行前
    Object object = point.proceed();
    //执行后
    return object;
    }
    
    }

    特别说明:ASP.NET CORE中的Fitler 与Spring MVC中的MethodInterceptor类似,都是控制方法,而ASP.NET CORE中的请求管道中间件与Spring MVC中的Filter、HandlerInterceptor类似,都是控制请求过程。这点要搞清楚。

    四、配置读取

    C#(支持多种配置数据提供程序,支持多种获取配置信息的方式,详见:ASP.NET Core 中的配置
    //Configuration为IConfiguration实例对象
    Configuration.GetValue("key");//适用单个key-value
    Configuration.Get<TConfig>();//适用整个config文件映射为一个TConfig类型的对象
    Configuration.GetSection("key").GetChildren();//获取子项集合
    JAVA(支持多种配置数据源格式(yml,Properties),可通过@value、@ConfigurationProperties、Environment等常见方法来获取配置信息)
    //1.通过@value方式获取配置信息
    @Value("${zuowenjun.site}")
    public String zwjSite;
    
    //2.通过创建一个映射配置信息的Bean(ConfigProperties) 方式获取配置信息
    @Component
    @ConfigurationProperties()//如果有前缀,则可以设置prefix=XXX
    public static class Zuowenjun {
    
    private String site;
    private String skills;
    private String motto;
    
    public String getSite() {
    return site;
    }
    
    public void setSite(String site) {
    this.site = site;
    }
    
    public String getSkills() {
    return skills;
    }
    
    public void setSkills(String skills) {
    this.skills = skills;
    }
    
    public String getMotto() {
    return motto;
    }
    
    public void setMotto(String motto) {
    this.motto = motto;
    }
    
    }
    
    //3.通过Environment来直接获取配置信息
    environment.getProperty("zuowenjun.site");

    五、发布、部署、运行

    C#(ASP.NET CORE:除了如下使用.NET CLI命今进行发布打包,也可以使用VS或VS CODE可视化操作进行发布操作)

    dotnet publish --configuration Release

    JAVA(Spring MVC:除了如下使用MAVEN命令进行清理打包,还可以使用IDEA来进行打包,具体方法可参见:Springboot项目打包成jar运行2种方式

    mvn clean package;

    C#(ASP.NET CORE)、JAVA(Spring MVC)都可以:

    1. 都支持WINDOWS服务器、Linux服务器等多种平台服务器 部署运行

    2. 都支持使用命令行启动运行ASP.NET CORE 或Spring MVC应用,例如:

      dotnet aspnetcoreApp.dll --urls="http://*:5001"

      java -jar springmvcApp.jar --server.port=5001

    3. 都支持Jenkins CI&CD ,Docker、k8s虚拟化部署

    4. 都支持在Linux服务器中以守护进程方式运行,例如:

      nohup dotnet aspnetcoreApp.dll > aspnetcoreApp.out 2>&1 &

      nohup java -jar springmvcApp.jar > springmvcApp.out 2>&1 &

      //或者都使用Supervisor来构建守护进程,还提供管理UI,具体请参见网上相关资源

    好了,总结到此结束,愿能帮助到那些处于.NET 转JAVA 或JAVA 转.NET或者想多了解一门编程语言的朋友们,祝大家事业有成。今后将分享更多关于分布式、算法等方面的知识,不局限.NET或JAVA语言,敬请期待,谢谢!

    码字不易,若需转载及转载我之前的文章请注明出处,谢谢。

  • 内容来自用户分享和网络整理,不保证内容的准确性,如有侵权内容,可联系管理员处理 点击这里给我发消息
    标签: 
    相关文章推荐