java中接口的妙用（二）

深碍√TFBOYSˉ_ 2023-10-16 20:37 33阅读 0赞

java中接口的妙用（二）:

**1. 写在前面：**

本例子是另外一篇博文“java中接口的妙用（一）”的姊妹篇。在进行程序设计时，通常会进行模块划分，从顶层到底层；而且，尽可能使各个模块进行松耦合，这样，当修单个模块时，做到不影响其它模块。  
下面这个例子，演示了如何进行分层设计，并且使用interface（接口）来进行数据的转移。  
  
  
**2. 例子业务说明：**  
本例子只是从技术角度出发，来说明“分层后，如何用inteface在层与层之间架起数据传递（处理）的桥梁，从而达到低耦合的目的。  
本例子只有一个业务，计算两个数的桑，如果除数为0时，进行了处理（逐级上报）。本例分为三层：  
用户层：就是有main函数的类；  
业务层：只能被用户层调用，通过interface将结果返回给用户层；  
系统层：只能被业务层调用通过interface将结果返回给业务层。

**3. 全部代码如下：**

**1）用户层：**  
  
  
//文件：JavaTest.java  
package com.my.test;  
  
  
import com.common.func.GetFunc\_Name;  
import com.module.business.BusinessInterface;  
import com.module.business.BusinessProcess;  
  
  
public class **JavaTest** \{  
  
private BusinessInterfaceImp mBusinessInterfaceImp = new BusinessInterfaceImp();  
  
int dataRes = -1;  
  
public static void main(String args\[\]) \{  
JavaTest test = new JavaTest();  
test.InterfaceTest();  
\}  
  
// 测试函数  
public void InterfaceTest() \{  
BusinessProcess bp = new BusinessProcess(mBusinessInterfaceImp);  
int x = 5;  
int y =2;  
System.out.println("TestCase 001, input:"+ "x = " + x + ", y = " +y);  
//调用业务层  
bp.**BusinessDevide**(x, y);  
System.out.println("TestCase 001, dataRes:"+ dataRes);  
  
  
dataRes = -1; //为了测试，这个结果值再归-1；  
  
int x1 = 10;  
int y1 = 0;  
System.out.println("\\n");  
System.out.println("TestCase 002, input:"+ "x1 = " + x1 + ", y1 = " +y1);  
//调用业务层  
bp.BusinessDevide(x1, y1);  
System.out.println("TestCase 002, dataRes:"+ dataRes);  
\}  
  
  
//BusinessInterface的实现类  
  
  
public class BusinessInterfaceImp implements BusinessInterface\{  
  
  
public void onBusinessResult(int type, int data) \{  
System.out.println("onBusinessResult " + data);  
dataRes = data; //这样，我们就达到了我们要的结果。  
\}  
  
  
  
public void onBusinessError(int type) \{  
System.out.println("onBusinessError ");  
  
\}  
  
\}  
  
  
public void Func() \{  
String str = "c.opj";  
int sub = str.lastIndexOf("/");  
String s = str.substring(sub+1);  
  
System.out.println("Str:" + str);  
System.out.println("s:" + s);  
System.out.println(GetFunc\_Name.\_FILE\_());  
System.out.println(GetFunc\_Name.\_FUNC\_());  
System.out.println(GetFunc\_Name.\_LINE\_());  
System.out.println(GetFunc\_Name.\_TIME\_());  
  
\}  
  
  
  
  
\}  
  
  
**2） 业务层：**  
  
  
//文件1：BusinessInterface.java  
package com.module.business;  
  
  
public interface **BusinessInterface** \{  
  
  
public void onBusinessResult(int type, int data);  
  
public void onBusinessError(int type);  
  
  
  
  
\}  
  
  
//文件2：BusinessProcess.java  
  
  
package com.module.business;  
  
  
import java.text.SimpleDateFormat;  
import java.util.Date;  
  
  
import com.module.system.SystemInterface;  
import com.module.system.SystemModule;  
  
  
  
  
public class **BusinessProcess** \{  
public static int Business\_OK = 1;  
public static int Business\_Error = 2;  
  
BusinessInterface bListener;  
  
public BusinessProcess(BusinessInterface bListener) \{  
this.bListener = bListener;  
\}  
  
  
private SystemInterface SystemInterfaceImpl = new SystemInterface() \{  
  
  
public int onSystemProcess(int error, int res) \{  
if (error < 0) \{  
//错误，返回Business\_Error  
bListener.onBusinessError(error);  
return Business\_Error;  
\}  
//正确，则将res继续返回上层  
bListener.onBusinessResult(error, res);  
return Business\_OK;  
  
\}  
\};  
  
//test function  
public int BusinessDevide(int x, int y) \{  
SystemModule s = new SystemModule(SystemInterfaceImpl);  
//调用系统层  
return s.devide(x, y);  
\}  
  
  
\}  
  
  
**3). 系统层：**  
//文件1：SystemInterface.java  
package com.module.system;  
  
  
public interface **SystemInterface** \{  
  
public int onSystemProcess(int error, int data);  
  
  
\}  
  
  
//文件2：SystemModule.java  
package com.module.system;  
  
  
public class **SystemModule** \{  
  
  
SystemInterface sListener;  
  
public SystemModule(SystemInterface sListener) \{  
this.sListener = sListener;  
\}  
  
//系统层的真正的计算函数  
public int devide(int x, int y) \{  
int res = -100;  
try \{  
res = x/y;  
return sListener.onSystemProcess(1, res);  
  
\}catch(Exception e) \{  
e.printStackTrace();  
return sListener.onSystemProcess(-1,res);  
\}  
  
\}  
  
  
\}  
  
  
**4. 测试结果：**  
  
  
TestCase 001, input:x = 5, y = 2  
onBusinessResult 2  
TestCase 001, dataRes:2  
  
  
  
  
TestCase 002, input:x1 = 10, y1 = 0  
onBusinessError  
TestCase 002, dataRes:-1  
java.lang.ArithmeticException: / by zero  
at com.module.system.SystemModule.devide(SystemModule.java:18)  
at com.module.business.BusinessProcess.BusinessDevide(BusinessProcess.java:38)  
at com.my.test.JavaTest.InterfaceTest(JavaTest.java:33)  
at com.my.test.JavaTest.main(JavaTest.java:15)  
  
  
**5. 附上： 代码目录结构：**  
  
  
  
  
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[Center]: https://img-blog.csdn.net/20141030185839052?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvbGlyYW5rZQ==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center