package com.kang.controller;

public class HelloController implements Controller {
    @Override
    public ModelAndView handleRequest(HttpServletRequest httpServletRequest,
                                      HttpServletResponse httpServletResponse) 
        throws Exception {
        ModelAndView mv = new ModelAndView();
        //Controller，需要返回一个ModelAndView对象
        //1、编写业务代码
        String result = "HelloSpringMVC";
        mv.addObject("msg",result); //将结果写到msg属性中
        //2、视图跳转，指定要跳转的jsp页面名字
        mv.setViewName("test"); 
        return mv;
    }
}

@Controller
public class HelloController {
    @RequestMapping("/hello1")
    public String myController(Model model){
        model.addAttribute("msg","hello,MVC-Annocation");
        return "hello"; 
    }
}

//表示类中每个方法的请求前都要加路径/test
@RequestMapping("/test")
public class HelloController {
    @RequestMapping("/hello")
    public String myController(){}
}

@RequestMapping(value = "/hello",method = RequestMethod.POST)

//方式一：直接返回视图名给视图解析器
@Controller
public class HelloController implements Controller {
    @RequestMapping("/hello")
    public String myController(){
        //1.做一些数据处理
        //2.返回视图名
        return "test";
    }
}
//方式二：使用ModelAndView设置视图名
@Controller
public class HelloController implements Controller {
    @RequestMapping("/hello")
    public ModelAndView myController(){
        ModelAndView mv = new ModelAndView();
        //1.做一些数据处理
        //2.设置要跳转的视图名，并返回此对象
        mv.setViewName("test");
        return mv;
    }
}

@Controller
public class ModelTest {
    @RequestMapping("/test2")
    public String  test2(){
        //return "/WEB-INF/jsp/hello.jsp";  //请求转发
        //return "forward:/WEB-INF/jsp/hello.jsp"; //请求转发
        return "redirect:/index.jsp"; //重定向,重定向的页面需要确保能够通过url访问
    }
}

@Controller
public class ModelTest1 {
    @RequestMapping("/test3")
    public void test3(HttpServletRequest request, 
                     HttpServletResponse response) 
        throws ServletException, IOException {
        request.setAttribute("msg","ModelTest1");
        request.getRequestDispatcher("/WEB-INF/jsp/hello.jsp").
            forward(request,response);
    }
}

@Controller
@RequestMapping("/user")
public class UserController {
    @PostMapping("/t1")
    public String acceptData(String name, Model model){
        //1.接收前端参数
        System.out.println(name);
        //2.做一些处理
        model.addAttribute("msg",name);
        //3.视图跳转
        return "hello";
    }
}

@Controller
@RequestMapping("/user")
public class UserController {
    @GetMapping("/t1")
    public String acceptData(@RequestParam("username")String name, Model model){
        //1.接收前端参数
        System.out.println(name);
        //2.将返回的结果传递给前端
        model.addAttribute("msg",name);
        //3.视图跳转
        return "hello";
    }
}

public class User {
    private int id;
    private String name;
    private int age;
}

@Controller
@RequestMapping("/user")
public class UserController {
    @GetMapping("/t2")
    public String test2(User user, Model model){
        //1.接收前端参数
        System.out.println(user);
        //2.处理数据
        model.addAttribute("msg","accept user");
        //3.视图跳转
        return "hello";
    }

@Controller
public class MyController {
    @RequestMapping("/hello")
    public String test(Model model){
        //调用addAttribute方法写入数据
        model.addAttribute("msg","hello,SpringMVC");
        return "hello"; 
    }
}

@Controller
public class MyController {
    @RequestMapping("/hello")
    public String test(ModelMap modelMap){
        modelMap.addAttribute("msg","hello,SpringMVC");
        return "hello"; 
    }
}

public class ModelMap extends LinkedHashMap<String, Object> {
    public ModelMap() {}
    ...
}

@Controller
public class HelloController {
    @RequestMapping("/hello")
    public ModelAndView myController(){
        ModelAndView mv = new ModelAndView();
        mv.addObject("msg","hello,SpringMVC"); //添加数据
        mv.setViewName("hello"); //指定视图名
        return mv;
    }
}

public class ModelAndView {
    @Nullable
    private Object view;  //视图名
    @Nullable
    private ModelMap model;  //保存数据
    @Nullable
    private HttpStatus status;
    private boolean cleared = false;

    public ModelAndView() {}
    //设置要跳转的视图名
    public void setViewName(@Nullable String viewName) {
        this.view = viewName;
    }
    //添加数据
    public ModelAndView addObject(String attributeName, 
                                  @Nullable Object attributeValue) {
        this.getModelMap().addAttribute(attributeName, attributeValue);
        return this;
    }
    ...
}

String str = new Gson().toJson(new User(1,"张三",24));

User user = new Gson().fromJson(str,User.class);

public class User {
    private int id;
    private String name;
    private int age;
    ...
}

@Controller
public class UserController {}
    @ResponseBody
    @RequestMapping(value = "/json")
    public String test(){
        User user = new User(1,"John",24);
        String str = new Gson().toJson(user);
        return str;
    }
}

@RestController
public class UserController {
    @RequestMapping(value = "/json")
    public String test(){
        User user = new User(1,"John",24);
        String str = new Gson().toJson(user);
        return str;
    }
}

@Controller
public class RestFulController {
    @RequestMapping(value = "/add/{a}/{b}",method = RequestMethod.POST)
    public String test1(@PathVariable int a, @PathVariable int b, Model model){
        int res = a+b;
        model.addAttribute("msg","Result 1:"+res);
        return "restful";
    }
    //URL相同时，可以根据不同的请求调用不同的方法
    @GetMapping("/add/{a}/{b}")
    public String test2(@PathVariable int a, @PathVariable int b, Model model){
        int res = a*b;
        model.addAttribute("msg","Result 2:"+res);
        return "restful";
    }
}

public class MyInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, 
                             HttpServletResponse response, Object handler) 
        throws Exception {
        System.out.println("=========处理前要执行的操作=========");
        return true; //true表示放行，执行下一个拦截器
    }

    /*
    postHandle和afterCompletion一般用于日志处理之类的后续工作
     */
    @Override
    public void postHandle(HttpServletRequest request, 
                           HttpServletResponse response, Object handler, 
                           ModelAndView modelAndView) throws Exception {
        System.out.println("=========处理后要执行的操作=========");
    }

    @Override
    public void afterCompletion(HttpServletRequest request,
                                HttpServletResponse response, 
                                Object handler, Exception ex) throws Exception {
        System.out.println("=========清理=========");
    }
}

/*
简单起见，用户名为“admin”，密码为“123456”，模拟从数据库中查询到的结果。
*/
@RestController
public class AjaxController {
    //登陆验证处理
    @RequestMapping("/login")
    public String login(String name,String pwd){
        String msg = "";
        if(name !=null){
            if("admin".equals(name)){
                msg="ok";
            }else{
                msg = "用户名不存在";
            }
        }
        if(pwd!=null){
            if("123456".equals(pwd)){
                msg="ok";
            }else{
                msg = "密码错误";
            }
        }
        return msg;
    }
}

@RestController
public class FileController {
    //@RequestParam("file") 将name=file控件得到的文件封装成CommonsMultipartFile对象
    //批量上传CommonsMultipartFile则为数组即可
    @RequestMapping("/upload")
    public String fileUpload(@RequestParam("file") CommonsMultipartFile file, 
                             HttpServletRequest request) throws IOException {

        //获取文件名 : file.getOriginalFilename();
        String uploadFileName = file.getOriginalFilename();

        //如果文件名为空，直接回到首页
        if ("".equals(uploadFileName)) {
            return "redirect:/index.jsp";
        }
        System.out.println("上传文件名 : " + uploadFileName);

        //上传路径保存设置
        String path = request.getServletContext().getRealPath("/upload");
        //如果路径不存在，创建一个
        File realPath = new File(path);
        if (!realPath.exists()) {
            realPath.mkdir();
        }
        System.out.println("上传文件保存地址：" + realPath);
        InputStream is = file.getInputStream(); //文件输入流
        OutputStream os = new FileOutputStream(
            new File(realPath, uploadFileName)); //文件输出流

        //读取写出
        int len = 0;
        byte[] buffer = new byte[1024];
        while ((len = is.read(buffer)) != -1) {
            os.write(buffer, 0, len);
            os.flush();
        }
        os.close();
        is.close();
        return "redirect:/index.jsp";
    }

    /*
     * 方式二：采用file.Transto 来保存上传的文件
     */
    @RequestMapping("/upload2")
    public String  fileUpload2(@RequestParam("file") CommonsMultipartFile file,
                               HttpServletRequest request) throws IOException {

        //上传路径保存设置
        String path = request.getServletContext().getRealPath("/upload");
        File realPath = new File(path);
        if (!realPath.exists()){
            realPath.mkdir();
        }
        //上传文件地址
        System.out.println("上传文件保存地址："+realPath);

        //通过CommonsMultipartFile的方法直接写文件
        file.transferTo(new File(realPath +"/"+ file.getOriginalFilename()));
        return "redirect:/index.jsp";
    }
}

@RestController
public class FileController {
    @RequestMapping(value="/download")
    public String downloads(HttpServletResponse response, 
                            HttpServletRequest request) throws Exception{
        //要下载的文件地址
        String  path = request.getServletContext().getRealPath("/upload");
        String  fileName = "test.txt";

        //1、设置response 响应头
        response.reset(); //设置页面不缓存,清空buffer
        response.setCharacterEncoding("UTF-8"); //字符编码
        response.setContentType("multipart/form-data"); //二进制传输数据
        //设置响应头
        response.setHeader("Content-Disposition",
                "attachment;fileName="+ URLEncoder.encode(fileName, "UTF-8"));

        File file = new File(path,fileName);
        //2、 读取文件--输入流
        InputStream input=new FileInputStream(file);
        //3、 写出文件--输出流
        OutputStream out = response.getOutputStream();

        byte[] buff =new byte[1024];
        int index=0;
        //4、执行 写出操作
        while((index= input.read(buff))!= -1){
            out.write(buff, 0, index);
            out.flush();
        }
        out.close();
        input.close();
        return null;
    }
}