项目理解（二）：Spring基础总结：Hello word-Thymeleaf-AOP-IOC

1. 写一个hello world：
   路径传参PathVariable RequestParam；请求传参method=RequestMethod.GET  ；

   //@RestController里面的方法都以JSON格式输出，不需要其它额外配置
   //@RestController  注解相当于@ResponseBody和@Controller合在一起的作用，如果web层
   // 的类上使用了@RestController注解，就代表这个类中所有的方法都会以JSON的形式返
   // 回，也相当于JSON的一种快捷返回方式
   //@Controller代表输出内容到页面
   @RestController
   public class IndexController {
   //  @RequestMapping提供路由信息；"/"路径的HTTP Request都会被映射到hello()方法上进行处理
   
   //web请求：controller----service-----DAO------Database
   //1通过路径传递
   //2通过请求参数传递
       @RequestMapping(path = {"/"} )
       @ResponseBody
       public String index(){
           return "Hello word!";
       }
   
       @RequestMapping(path = {"/","/index1"} , method = {RequestMethod.PUT})
       @ResponseBody
       public String index1(){
           return "Hello word!";
       }
   //
       @RequestMapping(path = {"/profile/{userId}"} )
       @ResponseBody
       public String profile(@PathVariable("userId") int userId){
           return String.format("profile page of %d", userId);
       }
       //
       @RequestMapping(path = {"/profile1/{userId}/{groupId}"} )
       @ResponseBody
       public String profile1(@PathVariable("userId") int userId, @PathVariable("groupId") String groupId){
           return String.format("profile page of %s ,k ;  %d", groupId, userId);
       }
   //
       @RequestMapping(path = {"/profile2/{userId}/{groupId}"} )
       @ResponseBody
       public String profile2(@PathVariable("userId") int userId, @PathVariable("groupId") String groupId,
                              @RequestParam("type") int type, @RequestParam("key") String key ){
           return String.format("profile page of %d, %s, t = %d, k = %s",userId, groupId ,type,key);
       }
   //
       @RequestMapping(path = {"/profile3/{userId}/{groupId}"} )
       @ResponseBody
       public String profile3(@PathVariable("userId") int userId, @PathVariable("groupId") String groupId,
                              @RequestParam(value = "type" , defaultValue = "1") int type ,
                              @RequestParam(value = "key" , defaultValue = "liu") String key ){
           return String.format("profile page of %s / %d, t:%d, k=%s", groupId, userId,type,key);
       }
   }
   

    

2. 单元测试：

   @RunWith(SpringRunner.class)
   @SpringBootTest
   public class WebControllerTest {
       private MockMvc mockMvc;
       @Before//在测试启动的时候优先执行，一般用作资源初始化
       public void setUp() throws Exception{
           mockMvc = MockMvcBuilders.standaloneSetup(new IndexController()).build();
       }
       @Test
       public void contextLoads() {
           System.out.println("Test!");
       }
       @Test
       public void getUser() throws Exception{
           String resposeString = mockMvc.perform(MockMvcRequestBuilders.
                   post("/getUser")).
                   andReturn().getResponse().getContentAsString();
           //获取请求的返回信息，并将返回信息转化为字符串，最后将请求的响应结果打印出来
           System.out.println("result: " + resposeString);
       }
       @Test
       public void getUsers() throws Exception{
           String resposeString = mockMvc.perform(MockMvcRequestBuilders.
                   get("/getUsersList")).
                   andReturn().getResponse().getContentAsString();
           //获取请求的返回信息，并将返回信息转化为字符串，最后将请求的响应结果打印出来
           System.out.println("results: " + resposeString);
       }
       @Test
       public void saveUsers() throws Exception{
           //数据校验
           mockMvc.perform(MockMvcRequestBuilders.post("/saveUser").
                   param("name", " ").param("age", "66").
                   param("pass","test")
           );
       }
   }

    

3. 数据校验：
    

   public class User {
   //    Hibernate Validator数据校验，包括了是否为空，长度，大小，特定格式等
       @NotEmpty(message = " 姓名不能为空")
       private String name;
       @Max(value = 100, message = " 年龄不能大于100岁")
       @Min(value = 20, message = " 年龄不能小于20岁")
       private int age;
       @NotEmpty(message = " 密码不能为空")
       @Length(min = 6,message = "密码长度不能小于6位")
       private String pass;
   
       public User(String name, int age, String pass) {
   
           this.name = name;
           this.age = age;
           this.pass = pass;
       }
       public String getName() {
           return name;
       }
       public int getAge() {
           return age;
       }
       public String getPass() {
           return pass;
       }
       public void setName(String name) {
           this.name = name;
       }
       public void setAge(int age) {
           this.age = age;
       }
       public void setPass(String pass) {
           this.pass = pass;
       }
   }

   在WebController中添加方法：saveUser

       @RequestMapping("/saveUser")
   //    BuildingResult参数检验的结果会存储在此对象中，可以根据属性来判断是否校验通过，校验不通过
   //    可以将错误信息打印出来
       public void saveUser(@Valid User user, BindingResult result ){
   //     @Valid参数前面添加@Valid注解，代表此对象使用了参数校验
           System.out.println("user:" + user);
           if(result.hasErrors()){
               List<ObjectError> list = result.getAllErrors();
               for(ObjectError error : list){
                   System.out.println(error.getCode()+"-" +error.getDefaultMessage());
               }
           }
       }

   
    
4. 自定义Filter：过滤器，可以在前端拦截所有用户的请求
   1实现Filter接口，实现其中的doFilter()方法：MyFilter类 ；MyFilter2类与MyFilter类相同。
   2添加@Configuration注解,将自定义Filter加入过滤链  WebConfiguration类

   public class MyFilter implements Filter {
   
       @Override
       public void init(FilterConfig filterConfig) throws ServletException {
   // TODO Auto-generated method stub
       }
   
       @Override
       public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse,
                            FilterChain filterChain) throws IOException, ServletException {
           HttpServletRequest request = (HttpServletRequest) servletRequest;
           System.out.println("this is MyFilter, url: " + request.getRequestURI());
           filterChain.doFilter(servletRequest, servletResponse);
       }
   
       @Override
       public void destroy() {
       // TODO Auto-generated method stub
       }
   }

   @Configuration
   public class WebConfiguration {
       @Bean
       public FilterRegistrationBean testFilterRegistration(){
           FilterRegistrationBean registration = new FilterRegistrationBean();
           registration.setFilter(new MyFilter());
           registration.addUrlPatterns("/*");
           registration.setOrder(6);
           return registration;
       }
       public FilterRegistrationBean test2FilterRegistration(){
           FilterRegistrationBean registration = new FilterRegistrationBean();
           registration.setFilter(new MyFilter2());
           registration.addUrlPatterns("/*");
           registration.setOrder(1);
           return registration;
       }
   }
   

    

5. 配置文件：application.properties中可以配置；或自己新增.properties配置文件（自定义配置文件）
   application.properties：

   neo.title=liu
   neo.description=technology
   
   spring.thymeleaf.cache=false

   other.properties:

6. other.title= keep smile
   other.blog=www.JD.com

    

7. 读取多个配置项：//定义一个NeoProperities对象，来接收所有以neo开头的配置内容

   NeoProperties.java
   @Component//定义为实例，方便在SpringBoot项目中引用
   @ConfigurationProperties(prefix = "neo")//定义一个NeoProperities对象，来接收所有以neo开头的配置内容
   public class NeoProperties {
       private String title;
       private String description;
   
       public String getTitle() {
           return title;
       }
   
       public String getDescription() {
           return description;
       }
   
       public void setTitle(String title) {
           this.title = title;
       }
   
       public void setDescription(String description) {
           this.description = description;
       }
   }
   
   otherProperties.java
   @Component//定义为实例，方便在SpringBoot项目中引用
   @ConfigurationProperties(prefix = "other")
   @PropertySource("classpath:other.properties")//多一个注解来指明配置文件地址
   public class otherProperties {
       private String title;
       private String blog;
   
       public String getTitle() {
           return title;
       }
   
       public  String getBlog() {
           return blog;
       }
   
       public void setTitle(String title) {
           this.title = title;
       }
   
       public void setBlog(String description) {
           this.blog = description;
       }
   }

   新建测试类进行测试：
    

   @RunWith(SpringRunner.class)
   @SpringBootTest
   public class PropertiesTest {
       @Value("${neo.title}")//会默认读取application.properties文件中的neo.title配置属性值，并赋给title
       private String title;//
       @Test
       public void testSingle(){
           Assert.assertEquals(title,"liu");//判断属性值是否与目标值一样
       }
   
       @Resource
       private NeoProperties properties;
       @Test
       public void testMore() throws Exception{
           System.out.println("title:"+properties.getTitle());
           System.out.println("description:"+properties.getDescription());
       }
   
       @Resource
       private otherProperties other;
       @Test
       public void testOther() throws Exception{
           System.out.println("title:"+ other.getTitle());
           System.out.println("blog:"+other.getBlog());
       }
   }
   

    

8. 模板引擎Thymeleaf基础使用：
   Thymeleaf旨在提供一个优雅的、高度可维护的创建模板的方式
   Thymeleaf 的作⽤域在 HTML 标签内，类似标签的⼀个属性来使⽤，这就是它的特点

   @Controller
   public class HelloController {
       @RequestMapping("/model")
       public String model(ModelMap map){
       map.addAttribute("message","http://www.JD.com");
       return "hello";//resolving template [hello],  when exist and  accessible
       }
   }

   上述会解析到resouces|templates|文件夹下的hello.html文件：
    

   <!DOCTYPE html>
   <html lang="en" xmlns:th="http://www.thymeleaf.org">
   #所有使⽤ Thymeleaf 的⻚⾯必须在 HTML 标签声明 Thymeleaf
   <head>
       <meta charset="UTF-8"></meta>
       <title>Hello</title>
   </head>
   <body>
   <h1  th:text="${message}">Hello World</h1>
   </body>
   </html>

   同理可得 （使用此模板）添加赋值、字符串拼接；条件判断If/unless; for循环；URL；三目运算；switch选择；等等功能。
   

   @Controller
   public class ExampleController {
   
   
       @RequestMapping("/if")
       public String ifunless(ModelMap map) {
           map.addAttribute("flag", "yes");
           return "if";
       }
   
       @RequestMapping("/list")
       public String list(ModelMap map) {
           map.addAttribute("users", getUserList());
           return "list";
   //        for循环：在页面中显示类似表格
       }
   
       @RequestMapping("/url")
       public String url(ModelMap map) {
           map.addAttribute("type", "liuzewei1996");
           map.addAttribute("pageId", "springcloud/2017/09/11/");
           map.addAttribute("img", "http://image.baidu.com");
           return "url";
       }
   
       @RequestMapping("/eq")
       public String eq(ModelMap map) {
           map.addAttribute("name", "neo");
           map.addAttribute("age", 30);
           map.addAttribute("flag", "yes");
           return "eq";
   //        三目运算符的使用
       }
   
       @RequestMapping("/switch")
       public String switchcase(ModelMap map) {
           map.addAttribute("sex", "woman");
           return "switch";
       }
   
       private List<User> getUserList(){
           List<User> list=new ArrayList<User>();
           User user1=new User("大牛",12,"123456");
           User user2=new User("小牛",6,"123563");
           User user3=new User("liu",66,"666666");
           list.add(user1);
           list.add(user2);
           list.add(user3);
           return  list;
       }
   
   }

   对应的HTML文件：
    

   <!DOCTYPE html>
   <html lang="en"  xmlns:th="http://www.thymeleaf.org">
   <head>
       <meta charset="UTF-8"></meta>
       <title>Example If/Unless </title>
   </head>
   <body>
   <div >
       <h1>If/Unless</h1>
       <a th:if="${flag == 'yes'}"  th:href="@{https://github.com/liuzewei1996}"> home </a>
       <br/>
       <a th:unless="${flag != 'no'}" th:href="@{http://www.JD.com/}" >JD</a>
   </div>
   </body>
   </html>
   
   
   <!DOCTYPE html>
   <html lang="en"  xmlns:th="http://www.thymeleaf.org">
   <head>
       <meta charset="UTF-8"></meta>
       <title>Example for </title>
   </head>
   <body>
   <div >
       <h1>for 循环</h1>
       <table>
           <tr  th:each="user,iterStat : ${users}">
               <td th:text="${user.name}">neo</td>
               <td th:text="${user.age}">6</td>
               <td th:text="${user.pass}">213</td>
               <td th:text="${iterStat.index}">index</td>
           </tr>
       </table>
   </div>
   </body>
   </html>
   
   
   
   <!DOCTYPE html>
   <html lang="en"  xmlns:th="http://www.thymeleaf.org">
   <head>
       <meta charset="UTF-8"></meta>
       <title>Example String </title>
   </head>
   <body>
       <div >
           <h1>text</h1>
           <p th:text="${userName}">neo</p>
           <span th:text="'Welcome to our application, ' + ${userName} + '!'"></span>
           <br/>
           <span th:text="|Welcome to our application, ${userName}!|"></span>
       </div>
   </body>
   </html>
   
   
   <!DOCTYPE html>
   <html lang="en"  xmlns:th="http://www.thymeleaf.org">
   <head>
       <meta charset="UTF-8"></meta>
       <title>Example switch </title>
   </head>
   <body>
   <div >
       <div th:switch="${sex}">
           <p th:case="'woman'">她是一个姑娘...</p>
           <p th:case="'man'">这是一个爷们!</p>
           <!-- *: case的默认的选项 -->
           <p th:case="*">未知性别的一个家伙。</p>
       </div>
   </div>
   </body>
   </html>
   
   <!DOCTYPE html>
   <html lang="en"  xmlns:th="http://www.thymeleaf.org">
   <head>
       <meta charset="UTF-8"></meta>
       <title>Example url </title>
   </head>
   <body>
   <div >
       <h1>URL</h1>
       <a  th:href="@{https://github.com/{type}(type=${type})}">link1</a>
       <br/>
       <a th:href="@{http://www.ityouknow.com/{pageId}/can-use-springcloud.html(pageId=${pageId})}">view</a>
       <br/>
       <div th:style="'background:url(' + @{${img}} + ');'">
           <br/><br/><br/>
       </div>
   </div>
   </body>
   </html>
   
   
   <!DOCTYPE html>
   <html lang="en"  xmlns:th="http://www.thymeleaf.org">
   <head>
       <meta charset="UTF-8"></meta>
       <title>Example gt eq  </title>
   </head>
   <body>
   <div >
       <h1>EQ</h1>
       <input th:value="${name}"/>
       <br/>
       <input th:value="${age gt 30 ? '中年':'年轻'}"/>
       <br/>
       <a th:if="${flag eq 'yes'}"  th:href="@{http://favorites.ren/}"> favorites </a>
   </div>
   </body>
   </html>

    

9. request/response:

       @RequestMapping("/request")
       @ResponseBody
       public String request(Model model, HttpServletResponse response,
                             HttpServletRequest request, HttpSession httpSession,
                             @CookieValue("JSESSIONID") String sessionId ){
           StringBuilder sb = new StringBuilder();
           sb.append("COOKIEVALUE:" +  sessionId);//方式一：可以通过注解的方式读取Cookie的值
           Enumeration<String> headerNames = request.getHeaderNames();
           while (headerNames.hasMoreElements()){
               String name = headerNames.nextElement();
               sb.append(name + ":" + request.getHeader(name) + "<br>");
           }
           if(request.getSession() != null){
               for(Cookie cookie : request.getCookies()){
                   sb.append("Cookie:"+ cookie.getName() + "value:" + cookie.getValue());
               }//方式二：此处读取Cookie的值（用户登录功能的实现可能用到这个值）
           }
   
           sb.append(request.getMethod()+"<br>");
           sb.append(request.getQueryString()+"<br>");
           sb.append(request.getPathInfo()+"<br>");
           sb.append(request.getRequestURL()+"<br>");
   
           //response是用来返回给用户的
           response.addHeader("Tianmensan", "hello");//字符串中不能有空格
           response.addCookie(new Cookie("username", "liu"));
           return sb.toString();
       }

    

10. 重定向（redirect）

        @RequestMapping(path = {"/redirect/{code}"}, method = {RequestMethod.GET})
    //    @ResponseBody//此行代码不需要
        public String redirect(@PathVariable("code") int code) {
            //重定向，页面的跳转
            return "redirect:/";//301跳转：永久转移、302跳转：临时转移
        }///  输入http://localhost:8080/redirect/301 直接跳转首页（http://localhost:8080），输出hello word
    
    
        @RequestMapping(path = {"/redirect/11/{code}"}, method = {RequestMethod.GET})
    //    @ResponseBody//此行代码不需要
        public String resee(@PathVariable("code") int code,
                            HttpSession httpSession) {
            //重定向，页面的跳转
            httpSession.setAttribute("msg", "jump to the massage");//可以将参数传递给要跳转的页面
            return "redirect:/";//301跳转：永久转移、302跳转：临时转移
        }

11. Error，错误异常处理

        @RequestMapping(path = {"/admin"}, method = {RequestMethod.GET})
        @ResponseBody
        public String admin(@RequestParam("key") String key){
            if("admin".equals(key)){
                return  "hello admin";
            }
            throw new IllegalArgumentException("参数不对");
        }
    
        @ExceptionHandler()//出现异常的处理函数
        @ResponseBody
        public String error(Exception e){
            return "error:" + e.getMessage();
        }

     

12. IOC：有很多个对象，通过依赖注入的方式将他们连接起来。控制反转。
    优点：无需关注变量的初始化；只要通过注解的方式来表示；

    @Controller
    public class SettingController {
    
        @Autowired//在用的地方这样依赖注入
        TestService testService;
    
        @RequestMapping(path = {"/setting"} ,method = {RequestMethod.GET})
        @ResponseBody
        public String setting(HttpSession httpSession){
            return "setting message" + testService.getMessage(12);
        }
    }
    
    @Service
    public class TestService {
        public String getMessage(int userId){
            return "test service:" + String.valueOf(userId);
        }
    }

     

13. AOP（面向切面的编程）

    @Aspect
    @Component
    public class LogAspect {
    //  面向切面编程
        public static final Logger logger = LoggerFactory.getLogger(LogAspect.class);
        @Before("execution(* com.example.templates.web.IndexController.*(..))")
        public void beforeMethod(JoinPoint joinPoint){
            StringBuilder sb = new StringBuilder();
            for(Object arg: joinPoint.getArgs()){//参数都保存到sb，后面打印出来
                sb.append("args:" + arg.toString() + "|");
            }
            logger.info("before method:"+ sb.toString());
            //在执行IndexController中任意方法是，先执行beforeMethod()
        }
    //*为通配符
        @After("execution(* com.example.templates.web.IndexController.*(..))")
        public void afterMethod(){
            logger.info("after method");//在执行IndexController中任意方法后，执行afterMethod()
        }
    }