手写简易版SpringIoc、SpringMvc

清疚 2022-12-18 13:55 234阅读 0赞

# 1 工程目录 #

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM0MTI1OTk5_size_16_color_FFFFFF_t_70_pic_center]

# 2 pom #

<properties>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>javax.servlet</groupId>
                <artifactId>javax.servlet-api</artifactId>
                <version>3.1.0</version>
                <scope>provided</scope>
            </dependency>
    
        </dependencies>
    
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.1</version>
                    <configuration>
                        <source>1.8</source>
                        <target>1.8</target>
                    </configuration>
                </plugin>
                <plugin>
                    <groupId>org.apache.tomcat.maven</groupId>
                    <artifactId>tomcat7-maven-plugin</artifactId>
                    <version>2.2</version>
                    <configuration>
                        <path>/</path>
                        <port>8080</port>
                    </configuration>
                </plugin>
            </plugins>
        </build>

# 3 web.xml #

<!DOCTYPE web-app PUBLIC
            "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
            "http://java.sun.com/dtd/web-app_2_3.dtd" >
    
    <web-app>
        <display-name>Rosh Created Web Application</display-name>
    
    
        <servlet>
            <servlet-name>roshmvc</servlet-name>
            <servlet-class>com.rosh.mvcframework.servlet.RoshDispatcherServlet</servlet-class>
            <init-param>
                <param-name>contextConfigLocation</param-name>
                <param-value>application.properties</param-value>
            </init-param>
            <load-on-startup>1</load-on-startup>
        </servlet>
    
    
        <servlet-mapping>
            <servlet-name>roshmvc</servlet-name>
            <url-pattern>/*</url-pattern> </servlet-mapping> </web-app>

# 4 application.properties #

scanPackage=com.rosh.demo

# 5 注解 #

@Target({ ElementType.TYPE})
    @Retention(RetentionPolicy.RUNTIME)
    @Documented
    public @interface RoshService { 
        String value() default "";
    }
    
    @Target({ ElementType.PARAMETER})
    @Retention(RetentionPolicy.RUNTIME)
    @Documented
    public @interface RoshRequestParam { 
        String value() default "";
    }
    
    @Target({ ElementType.TYPE,ElementType.METHOD})
    @Retention(RetentionPolicy.RUNTIME)
    @Documented
    public @interface RoshRequestMapping { 
        String value() default "";
    }
    
    
    @Target({ ElementType.TYPE})
    @Retention(RetentionPolicy.RUNTIME)
    @Documented
    public @interface RoshController { 
    
        String value() default "";
    }
    
    @Target({ ElementType.FIELD})
    @Retention(RetentionPolicy.RUNTIME)
    @Documented
    public @interface RoshAutowired { 
        String value() default "";
    }

# 6 RoshDispatcherServlet #

package com.rosh.mvcframework.servlet;
    
    import com.rosh.mvcframework.annotation.RoshAutowired;
    import com.rosh.mvcframework.annotation.RoshController;
    import com.rosh.mvcframework.annotation.RoshRequestMapping;
    import com.rosh.mvcframework.annotation.RoshService;
    
    import javax.servlet.ServletConfig;
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.File;
    import java.io.IOException;
    import java.io.InputStream;
    import java.lang.reflect.Field;
    import java.lang.reflect.Method;
    import java.net.URL;
    import java.util.*;
    
    public class RoshDispatcherServlet extends HttpServlet { 
    
    
        private Properties contextConfig = new Properties();
    
        private List<String> classNames = new ArrayList<>();
    
        private Map<String, Object> ioc = new HashMap<>();
    
        private Map<String, Method> handlerMapping = new HashMap<>();
    
    
        @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 
            this.doPost(req, resp);
        }
    
        @Override
        protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 
    
            //调用
            try { 
                doDispatch(req, resp);
            } catch (Exception e) { 
                e.printStackTrace();
            }
    
        }
    
        private void doDispatch(HttpServletRequest req, HttpServletResponse resp) throws Exception { 
    
            //绝对路径
            String url = req.getRequestURI();
            //相对路径
            String contextPath = req.getContextPath();
            url = url.replaceAll(contextPath, "").replaceAll("/+", "/");
    
            if (this.handlerMapping.containsKey(url)) { 
    
                Method method = this.handlerMapping.get(url);
                //beanname
                String beanName = toLowerFirstCase(method.getDeclaringClass().getSimpleName());
                //参数
                Map<String, String[]> parameterMap = req.getParameterMap();
    
                method.invoke(ioc.get(beanName), new Object[]{ req, resp, parameterMap.get("name")[0]});
            } else { 
                resp.getWriter().write("404 Not Found!!!!");
            }
    
    
        }
    
    
        @Override
        public void init(ServletConfig config) throws ServletException { 
    
            //1 加载配置文件
            doLoadConfig(config.getInitParameter("contextConfigLocation"));
            //2 扫描相关类
            doScanner(contextConfig.getProperty("scanPackage"));
            //3 初始化扫描到的类，并且将他们放入到IOC容器中
            doInstance();
            //4 完成依赖注入
            doAutowired();
            //5 初始化HandlerMapping
            initHandlerMapping();
    
            System.out.println("Rosh Spring framework is init.");
        }
    
        /** * 映射 */
        private void initHandlerMapping() { 
            if (!ioc.isEmpty()) { 
                for (Map.Entry<String, Object> entry : ioc.entrySet()) { 
                    Class<?> clazz = entry.getValue().getClass();
                    if (clazz.isAnnotationPresent(RoshController.class)) { 
                        String baseUrl = "";
                        if (clazz.isAnnotationPresent(RoshRequestMapping.class)) { 
                            RoshRequestMapping requestMapping = clazz.getAnnotation(RoshRequestMapping.class);
                            baseUrl = requestMapping.value();
                        }
                        //获取所有public 方法
                        Method[] methods = clazz.getMethods();
                        for (Method method : methods) { 
                            if (method.isAnnotationPresent(RoshRequestMapping.class)) { 
                                RoshRequestMapping requestMapping = method.getAnnotation(RoshRequestMapping.class);
                                String url = (baseUrl + "/" + requestMapping.value()).replaceAll("/+", "/");
                                handlerMapping.put(url, method);
                            }
                        }
    
                    }
    
                }
            }
    
    
        }
    
        /** * 自动注入 */
        private void doAutowired() { 
            if (!ioc.isEmpty()) { 
    
                for (Map.Entry<String, Object> entry : ioc.entrySet()) { 
                    //所有字段
                    Field[] fields = entry.getValue().getClass().getDeclaredFields();
                    for (Field field : fields) { 
                        if (field.isAnnotationPresent(RoshAutowired.class)) { 
                            RoshAutowired autowired = field.getAnnotation(RoshAutowired.class);
                            String beanName = autowired.value();
                            if ("".endsWith(beanName)) { 
                                beanName = field.getType().getName();
                            }
                            field.setAccessible(true);
                            try { 
                                //反射机制，动态赋值
                                field.set(entry.getValue(), ioc.get(beanName));
                            } catch (IllegalAccessException e) { 
                                e.printStackTrace();
                            }
                        }
                    }
                }
            }
    
    
        }
    
        /** * 初始化 */
        private void doInstance() { 
    
            if (classNames.isEmpty()) { 
                return;
            }
    
            try { 
                for (String className : classNames) { 
                    Class<?> clazz = Class.forName(className);
                    //判断注解
                    if (clazz.isAnnotationPresent(RoshController.class)) { 
                        Object o = clazz.newInstance();
                        String beanName = toLowerFirstCase(clazz.getSimpleName());
                        ioc.put(beanName, o);
                    } else if (clazz.isAnnotationPresent(RoshService.class)) { 
    
                        //1 默认beanName
                        String beanName = toLowerFirstCase(clazz.getSimpleName());
                        //2 自定义beanName
                        RoshService roshService = clazz.getAnnotation(RoshService.class);
                        if (!"".endsWith(roshService.value())) { 
                            beanName = roshService.value();
                        }
                        Object o = clazz.newInstance();
                        ioc.put(beanName, o);
                        //3 根据类型自动赋值
                        for (Class<?> i : clazz.getInterfaces()) { 
                            if (!ioc.containsKey(i.getName())) { 
                                ioc.put(i.getName(), o);
                            }
                        }
                    }
                }
            } catch (Exception e) { 
                e.printStackTrace();
            }
    
        }
    
        private String toLowerFirstCase(String simpleName) { 
            char[] chars = simpleName.toCharArray();
            chars[0] += 32;
            return String.valueOf(chars);
        }
    
        /** * 扫描出相关的类 */
        private void doScanner(String scanPackage) { 
            //获取类文件url
            URL url = this.getClass().getClassLoader().getResource(scanPackage.replaceAll("\\.", "/"));
            //读取当前类文件
            File rootFile = new File(url.getFile());
            //遍历
            for (File file : rootFile.listFiles()) { 
                if (file.isDirectory()) { 
                    doScanner(scanPackage + "." + file.getName());
                } else { 
                    if (!file.getName().endsWith(".class")) { 
                        continue;
                    }
                    //获取类名
                    String className = scanPackage + "." + file.getName().replace(".class", "");
                    classNames.add(className);
                }
    
            }
    
        }
    
        /** * 加载配置文件 */
        private void doLoadConfig(String contextConfigLocation) { 
            InputStream is = this.getClass().getClassLoader().getResourceAsStream(contextConfigLocation);
            try { 
                contextConfig.load(is);
            } catch (IOException e) { 
                e.printStackTrace();
            } finally { 
                if (is != null) { 
                    try { 
                        is.close();
                    } catch (IOException e) { 
                        e.printStackTrace();
                    }
                }
            }
    
        }
    
    
    }

# 7 业务类 #

@RoshController
    @RoshRequestMapping("/student")
    public class StudentController { 
    
        @RoshAutowired
        private StudentService studentService;
    
    
        @RoshRequestMapping("/query")
        public void query(HttpServletRequest req, HttpServletResponse resp,
                          @RoshRequestParam("name") String name) { 
            String result = "<h1>My name is " + name + "</h1>";
            try { 
                resp.getWriter().write(result);
            } catch (IOException e) { 
                e.printStackTrace();
            }
        }
    
    
    }
    
    
    public interface StudentService { 
    }
    
    @RoshService
    public class StudentServiceImpl implements StudentService { 
    }

# 8 测试 #

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM0MTI1OTk5_size_16_color_FFFFFF_t_70_pic_center 1]

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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM0MTI1OTk5_size_16_color_FFFFFF_t_70_pic_center 1]: /images/20221122/49db2283924344728d2c2abc986c0866.png