写简单的mvc框架实例讲解

import com.hebaibai.amvc.requesttype;
import java.lang.annotation.*;

/**
 * 表示这个类中的，添加了@request注解的method被映射为一个http地址。
 *
 * @author hjx
 */
@documented
@target({elementtype.method, elementtype.type})
@retention(retentionpolicy.runtime)
public @interface request {

  /**
   * 请求类型
   * 支持get，post，delete，put
   *
   * @return
   */
  requesttype[] type() default {requesttype.get, requesttype.post, requesttype.delete, requesttype.put};

  /**
   * 请求地址
   * 添加在class上时，会将value中的值添加在其他方法上的@request.value()的值前，作为基础地址。
   *
   * @return
   */
  string value() default "/";
}

{
 "annotationsupport": true,
 "annotationpackage": "com.hebaibai.demo.web",
// "mapping": [
//  {
//   "url": "/index",
//   "requesttype": [
//    "get"
//   ],
//   "method": "index",
//   "objectclass": "com.hebaibai.demo.web.indexcontroller",
//   "paramtypes": [
//    "java.lang.string",
//    "int"
//   ]
//  }
// ]
}

/**
 * 从给定的报名中找出所有的class
 *
 * @param packagename
 * @param classes
 */
@sneakythrows({ioexception.class})
public static void getclassbypackage(string packagename, set<class> classes) {
  assert.notnull(classes);
  string packagepath = packagename.replace(dot, slash);
  enumeration<url> resources = classutils.getclassloader().getresources(packagepath);
  while (resources.hasmoreelements()) {
    url url = resources.nextelement();
    //文件类型
    string protocol = url.getprotocol();
    string filepath = urldecoder.decode(url.getfile(), charset_utf_8);
    if (type_file.equals(protocol)) {
      getclassbyfilepath(packagename, filepath, classes);
    }
    if (type_jar.equals(protocol)) {
      //截取文件的路径
      filepath = filepath.substring(filepath.indexof(":") + 1, filepath.indexof("!"));
      getclassbyjarpath(packagename, filepath, classes);
    }
  }
}

/**
 * 在文件夹中递归找出该文件夹中在package中的class
 *
 * @param packagename
 * @param filepath
 * @param classes
 */
static void getclassbyfilepath(
  string packagename,
  string filepath,
  set<class> classes
) {
  file targetfile = new file(filepath);
  if (!targetfile.exists()) {
    return;
  }
  if (targetfile.isdirectory()) {
    file[] files = targetfile.listfiles();
    for (file file : files) {
      string path = file.getpath();
      getclassbyfilepath(packagename, path, classes);
    }
  } else {
    //如果是一个class文件
    boolean trueclass = filepath.endswith(class_mark);
    if (trueclass) {
      //提取完整的类名
      filepath = filepath.replace(slash, dot);
      int i = filepath.indexof(packagename);
      string classname = filepath.substring(i, filepath.length() - 6);
      //不是一个内部类
      boolean notinnerclass = classname.indexof("$") == -1;
      if (notinnerclass) {
        //根据类名加载class对象
        class aclass = classutils.forname(classname);
        if (aclass != null) {
          classes.add(aclass);
        }
      }
    }
  }
}

/**
 * 在jar文件中找出该文件夹中在package中的class
 *
 * @param packagename
 * @param filepath
 * @param classes
 */
@sneakythrows({ioexception.class})
static void getclassbyjarpath(
  string packagename,
  string filepath,
  set<class> classes
) {
  jarfile jarfile = new urljarfile(new file(filepath));
  enumeration<jarentry> entries = jarfile.entries();
  while (entries.hasmoreelements()) {
    jarentry jarentry = entries.nextelement();
    string jarentryname = jarentry.getname().replace(slash, dot);
    //在package下的class
    boolean trueclass = jarentryname.endswith(class_mark) && jarentryname.startswith(packagename);
    //不是一个内部类
    boolean notinnerclass = jarentryname.indexof("$") == -1;
    if (trueclass && notinnerclass) {
      string classname = jarentryname.substring(0, jarentryname.length() - 6);
      system.out.println(classname);
      //根据类名加载class对象
      class aclass = classutils.forname(classname);
      if (aclass != null) {
        classes.add(aclass);
      }
    }
  }
}

/**
 * 通过解析class 获取映射
 *
 * @param aclass
 * @return
 */
public list<urlmethodmapping> geturlmethodmappinglistbyclass(class<request> aclass) {
  list<urlmethodmapping> mappings = new arraylist<>();
  request request = aclass.getdeclaredannotation(request.class);
  if (request == null) {
    return mappings;
  }
  string basepath = request.value();
  for (method classmethod : aclass.getdeclaredmethods()) {
    urlmethodmapping urlmethodmapping = geturlmethodmappinglistbymethod(classmethod);
    if (urlmethodmapping == null) {
      continue;
    }
    //将添加在class上的request中的path作为基础路径
    string url = urlutils.makeurl(basepath + "/" + urlmethodmapping.geturl());
    urlmethodmapping.seturl(url);
    mappings.add(urlmethodmapping);
  }
  return mappings;
}

/**
 * 通过解析method 获取映射
 * 注解request不存在时跳出
 *
 * @param method
 * @return
 */
private urlmethodmapping geturlmethodmappinglistbymethod(method method) {
  request request = method.getdeclaredannotation(request.class);
  if (request == null) {
    return null;
  }
  class<?> declaringclass = method.getdeclaringclass();
  string path = request.value();
  for (char c : path.tochararray()) {
    assert.istrue(c != ' ', declaringclass + "." + method.getname() + "请求路径异常：" + path + " ！");
  }
  return geturlmethodmapping(
      path,
      request.type(),
      declaringclass,
      method,
      method.getparametertypes()
  );
}

private static final string slash = "/";

/**
 * 处理url
 * 1：去掉连接中相邻并重复的“/”,
 * 2：链接开头没有“/”,则添加。
 * 3：链接结尾有“/”，则去掉。
 *
 * @param url
 * @return
 */
public static string makeurl(@nonnull string url) {
  char[] chars = url.tochararray();
  stringbuilder newurl = new stringbuilder();
  if (!url.startswith(slash)) {
    newurl.append(slash);
  }
  for (int i = 0; i < chars.length; i++) {
    if (i != 0 && chars[i] == chars[i - 1] && chars[i] == '/') {
      continue;
    }
    if (i == chars.length - 1 && chars[i] == '/') {
      continue;
    }
    newurl.append(chars[i]);
  }
  return newurl.tostring();
}

/**
 * 使用注解来加载urlmethodmapping
 *
 * @param configjson
 */
private void addapplicationurlmappingbyannotationconfig(jsonobject configjson) {
  string annotationpackage = configjson.getstring(annotation_package_node);
  assert.notnull(annotationpackage, annotation_package_node + not_find);
  //获取添加了@request的类
  set<class> classes = new hashset<>();
  classutils.getclassbypackage(annotationpackage, classes);
  iterator<class> iterator = classes.iterator();
  while (iterator.hasnext()) {
    class aclass = iterator.next();
    list<urlmethodmapping> mappings = urlmethodmappingfactory.geturlmethodmappinglistbyclass(aclass);
    if (mappings.size() == 0) {
      continue;
    }
    for (urlmethodmapping mapping : mappings) {
      addapplicationurlmapping(mapping);
    }
  }
}

/**
 * 使用文件配置来加载urlmethodmapping
 * 配置中找不到的话不执行。
 *
 * @param configjson
 */
private void addapplicationurlmappingbyjsonconfig(jsonobject configjson) {
  jsonarray jsonarray = configjson.getjsonarray(mapping_node);
  if (jsonarray == null || jsonarray.size() == 0) {
    return;
  }
  for (int i = 0; i < jsonarray.size(); i++) {
    urlmethodmapping mapping = urlmethodmappingfactory.geturlmethodmappingbyjson(jsonarray.getjsonobject(i));
    addapplicationurlmapping(mapping);
  }
}

/**
 * 初始化配置
 */
@sneakythrows(ioexception.class)
protected void init() {
  string configfilename = applicationname + ".json";
  inputstream inputstream = classutils.getclassloader().getresourceasstream(configfilename);
  byte[] bytes = new byte[inputstream.available()];
  inputstream.read(bytes);
  string config = new string(bytes, "utf-8");
  //应用配置
  jsonobject configjson = jsonobject.parseobject(config);

  //todo:生成对象的工厂类（先默认为每次都new一个新的对象）
  this.objectfactory = new alwaysnewobjectfactory();
  //todo:不同的入参名称获取类（当前默认为asm）
  urlmethodmappingfactory.setparamnamegetter(new asmparamnamegetter());
  //通过文件配置加载
  addapplicationurlmappingbyjsonconfig(configjson);
  //是否开启注解支持
  boolean annotationsupport = configjson.getboolean(annotation_support_node);
  assert.notnull(annotationsupport, annotation_support_node + not_find);
  if (annotationsupport) {
    addapplicationurlmappingbyannotationconfig(configjson);
  }
}