java.lang.IllegalStateException: No primary or single public constructor found for interface javax.servlet.ServletContext - and no default constructor found either
// 获取ServletContext对象的方法二：从 IOC 容器中直接注入
@Autowired
private ServletContext servletContext;
@RequestMapping("/original/servlet/context/second/way")
public String originalServletContextSecondWay() {
logger.debug(this.servletContext.toString());
return "target";
}
4、原生对象和 IOC 容器关系
第二节 属性域
1、在整个应用中属性域的重要作用
2、请求域操作方式
①使用 Model 类型的形参
@RequestMapping("/attr/request/model")
public String testAttrRequestModel(
// 在形参位置声明Model类型变量，用于存储模型数据
Model model) {
// 我们将数据存入模型，SpringMVC 会帮我们把模型数据存入请求域
// 存入请求域这个动作也被称为暴露到请求域
model.addAttribute("requestScopeMessageModel","i am very happy[model]");
return "target";
}
②使用 ModelMap 类型的形参
@RequestMapping("/attr/request/model/map")
public String testAttrRequestModelMap(
// 在形参位置声明ModelMap类型变量，用于存储模型数据
ModelMap modelMap) {
// 我们将数据存入模型，SpringMVC 会帮我们把模型数据存入请求域
// 存入请求域这个动作也被称为暴露到请求域
modelMap.addAttribute("requestScopeMessageModelMap","i am very happy[model map]");
return "target";
}
③使用 Map 类型的形参
@RequestMapping("/attr/request/map")
public String testAttrRequestMap(
// 在形参位置声明Map类型变量，用于存储模型数据
Map map) {
// 我们将数据存入模型，SpringMVC 会帮我们把模型数据存入请求域
// 存入请求域这个动作也被称为暴露到请求域
map.put("requestScopeMessageMap", "i am very happy[map]");
return "target";
}
④使用原生 request 对象
@RequestMapping("/attr/request/original")
public String testAttrOriginalRequest(
// 拿到原生对象，就可以调用原生方法执行各种操作
HttpServletRequest request) {
request.setAttribute("requestScopeMessageOriginal", "i am very happy[original]");
return "target";
}
⑤使用 ModelAndView 对象
@RequestMapping("/attr/request/mav")
public ModelAndView testAttrByModelAndView() {
// 1.创建ModelAndView对象
ModelAndView modelAndView = new ModelAndView();
// 2.存入模型数据
modelAndView.addObject("requestScopeMessageMAV", "i am very happy[mav]");
// 3.设置视图名称
modelAndView.setViewName("target");
return modelAndView;
}
@Override
public void handleRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
Assert.state(this.servletContext != null, "No ServletContext set");
RequestDispatcher rd = this.servletContext.getNamedDispatcher(this.defaultServletName);
if (rd == null) {
throw new IllegalStateException("A RequestDispatcher could not be located for the default servlet '" +
this.defaultServletName + "'");
}
// 这里执行请求转发操作
rd.forward(request, response);
}
public class John {
private List seasonList;
public List getSeasonList() {
return seasonList;
}
public void setSeasonList(List seasonList) {
this.seasonList = seasonList;
}
}
handler方法
@RequestMapping("/form/redisplay/choose/multi")
public String chooseMulti(Model model) {
// 1.准备用来显示标签的数据
List seasonList = new ArrayList<>();
seasonList.add(new Season("spring", "春天"));
seasonList.add(new Season("summer", "夏天"));
seasonList.add(new Season("autumn", "秋天"));
seasonList.add(new Season("winter", "冬天"));
model.addAttribute("seasonList", seasonList);
// 2.准备用来回显表单的实体类数据
John john = new John();
List seasonListForRedisplay = new ArrayList<>();
seasonListForRedisplay.add(new Season("summer", "夏天"));
seasonListForRedisplay.add(new Season("winter", "冬天"));
model.addAttribute("seasonListForRedisplay", seasonListForRedisplay);
return "form-multi";
}
页面标签
注意：此时需要判断一个对象是否在集合中，那就需要重写equals()和hashCode()方法。
第六节 案例
1、准备工作
①创建实体类
public class Movie {
private String movieId;
private String movieName;
private Double moviePrice;
……
②创建Service
[1]接口
public interface MovieService {
List getAll();
Movie getMovieById(String movieId);
void saveMovie(Movie movie);
void updateMovie(Movie movie);
void removeMovieById(String movieId);
}
[2]接口的实现类
@Service
public class MovieServiceImpl implements MovieService {
private static Map movieMap;
static {
movieMap = new HashMap<>();
String movieId = null;
Movie movie = null;
movieId = UUID.randomUUID().toString().replace("-", "").toUpperCase();
movie = new Movie(movieId, "肖申克救赎", 10.0);
movieMap.put(movieId, movie);
movieId = UUID.randomUUID().toString().replace("-", "").toUpperCase();
movie = new Movie(movieId, "泰坦尼克号", 20.0);
movieMap.put(movieId, movie);
movieId = UUID.randomUUID().toString().replace("-", "").toUpperCase();
movie = new Movie(movieId, "审死官", 30.0);
movieMap.put(movieId, movie);
movieId = UUID.randomUUID().toString().replace("-", "").toUpperCase();
movie = new Movie(movieId, "大话西游之大圣娶亲", 40.0);
movieMap.put(movieId, movie);
movieId = UUID.randomUUID().toString().replace("-", "").toUpperCase();
movie = new Movie(movieId, "大话西游之仙履奇缘", 50.0);
movieMap.put(movieId, movie);
movieId = UUID.randomUUID().toString().replace("-", "").toUpperCase();
movie = new Movie(movieId, "功夫", 60.0);
movieMap.put(movieId, movie);
movieId = UUID.randomUUID().toString().replace("-", "").toUpperCase();
movie = new Movie(movieId, "大内密探凌凌漆", 70.0);
movieMap.put(movieId, movie);
movieId = UUID.randomUUID().toString().replace("-", "").toUpperCase();
movie = new Movie(movieId, "食神", 80.0);
movieMap.put(movieId, movie);
movieId = UUID.randomUUID().toString().replace("-", "").toUpperCase();
movie = new Movie(movieId, "西游降魔篇", 90.0);
movieMap.put(movieId, movie);
movieId = UUID.randomUUID().toString().replace("-", "").toUpperCase();
movie = new Movie(movieId, "西游伏妖篇", 11.0);
movieMap.put(movieId, movie);
movieId = UUID.randomUUID().toString().replace("-", "").toUpperCase();
movie = new Movie(movieId, "三傻大闹宝莱坞", 12.0);
movieMap.put(movieId, movie);
movieId = UUID.randomUUID().toString().replace("-", "").toUpperCase();
movie = new Movie(movieId, "唐人街探案", 13.0);
movieMap.put(movieId, movie);
movieId = UUID.randomUUID().toString().replace("-", "").toUpperCase();
movie = new Movie(movieId, "一个人的武林", 14.0);
movieMap.put(movieId, movie);
movieId = UUID.randomUUID().toString().replace("-", "").toUpperCase();
movie = new Movie(movieId, "罗马假日", 15.0);
movieMap.put(movieId, movie);
movieId = UUID.randomUUID().toString().replace("-", "").toUpperCase();
movie = new Movie(movieId, "花季雨季", 16.0);
movieMap.put(movieId, movie);
movieId = UUID.randomUUID().toString().replace("-", "").toUpperCase();
movie = new Movie(movieId, "夏洛特烦恼", 17.0);
movieMap.put(movieId, movie);
}
@Override
public List getAll() {
return new ArrayList<>(movieMap.values());
}
@Override
public Movie getMovieById(String movieId) {
return movieMap.get(movieId);
}
@Override
public void saveMovie(Movie movie) {
String movieId = UUID.randomUUID().toString().replace("-", "");
movie.setMovieId(movieId);
movieMap.put(movieId, movie);
}
@Override
public void updateMovie(Movie movie) {
String movieId = movie.getMovieId();
movieMap.put(movieId, movie);
}
@Override
public void removeMovieById(String movieId) {
movieMap.remove(movieId);
}
}
③测试Service
@SpringJUnitConfig(locations = {"classpath:spring-mvc.xml"})
public class MovieTest {
@Autowired
private MovieService movieService;
@Test
public void testServiceGetAll() {
List list = movieService.getAll();
for (Movie movie : list) {
System.out.println("movie = " + movie);
}
}
@Test
public void testServiceGetById() {
List movieList = movieService.getAll();
for (Movie movie : movieList) {
String movieId = movie.getMovieId();
Movie movieById = movieService.getMovieById(movieId);
System.out.println("movieById = " + movieById);
}
}
@Test
public void testGetOne() {
Movie movie = movieService.getMovieById("178E6B0B0DA14DC59141E06FFA620673");
System.out.println("movie = " + movie);
}
@Test
public void testServiceRemoveById() {
List movieList = movieService.getAll();
for (Movie movie : movieList) {
String movieId = movie.getMovieId();
movieService.removeMovieById(movieId);
}
movieList = movieService.getAll();
for (Movie movie : movieList) {
System.out.println("movie = " + movie);
}
}
@Test
public void testServiceSave() {
movieService.saveMovie(new Movie(null, "aa", 111.11));
List all = movieService.getAll();
for (Movie movie : all) {
System.out.println("movie = " + movie);
}
}
@Test
public void testServiceUpdate() {
List all = movieService.getAll();
for (Movie movie : all) {
String movieId = movie.getMovieId();
String movieName = movie.getMovieName() + "~";
Movie movieNew = new Movie(movieId, movieName, movie.getMoviePrice());
movieService.updateMovie(movieNew);
}
List movieList = movieService.getAll();
for (Movie movie : movieList) {
System.out.println("movie = " + movie);
}
}
}
