返回值分类：
@RequestMapping("testModelAndView")
public ModelAndView testModelAndView(){
//创建 ModelAndView 对象
ModelAndView mv = new ModelAndView();
System.out.println("testModelAndView执行了……");
// 模拟从数据库中查询出User对象
User user = new User();
user.setUsername("jljl");
user.setPassword("456");
user.setAge(22);
//把 user 对象存储到 mv 对象中，也会把 user 对象存入到 request 对象
mv.addObject("user",user);
//跳转到哪个页面,ModelAndView会找到视图解析器，找到其对应的目录下的页面
mv.setViewName("success");
return mv;
}
SpringMVC 框架提供的 转发 和 重定向
/**
* 使用关键字的方式进行转发或者重定向
* @return
*/
@RequestMapping("testForwardOrRedict")
public String testForwardOrRedict(){
System.out.println("testForwardOrRedict执行了……");
//请求的转发
//return "forward:/WEB-INF/pages/success.jsp";
//重定向
return "redirect:/index.jsp";
}
ResponseBody 响应 json 数据
<!--前端控制器，哪些静态资源不拦截-->
<mvc:resources location="/js/" mapping="/js/**"/>
<!--新的设置方式，可以设置不拦截所有静态资源-->
<!--<mvc:default-servlet-handler/>-->
<script src="${pageContext.request.contextPath}/js/jquery-3.1.1.min.js"></script>
<script>
//页面加载，绑定单击事件
$(function () {
$("#btn").click(function () {
//发送ajax请求
$.ajax({
url:"${pageContext.request.contextPath}/user/testAjax",
contentType:"application/json;charset=utf-8",
data:'{"username":"jinlu","password":"123","age":22}',
dataType:"json",
type:"post",
success:function (data) {
//data：服务器响应的 json 数据，进行解析
}
});
});
});
</script>
<button id="btn">发送 ajax 请求</button>
/**
* 模拟异步请求响应
*/
@RequestMapping("testAjax")
public void testAjax(@RequestBody String body){
System.out.println("testAjax执行了……");
System.out.println(body);
}
响应 json 数据格式
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.9.0</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>2.9.0</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-annotations</artifactId>
<version>2.9.0</version>
</dependency>
<script>
//页面加载，绑定单击事件
$(function () {
$("#btn").click(function () {
//alert("hello btn");
//发送ajax请求
$.ajax({
url:"${pageContext.request.contextPath}/user/testAjax",
contentType:"application/json;charset=utf-8",
data:'{"username":"jinlu","password":"123","age":22}',
dataType:"json",
type:"post",
success:function (data) {
//data：服务器响应的 json 数据，进行解析
alert(data);
alert(data.username);
alert(data.password);
alert(data.age);
}
});
});
});
</script>
@RequestMapping("testAjax")
public @ResponseBody User testAjax(@RequestBody User user){
System.out.println("testAjax执行了……");
//客户端发送ajax请求，传的是json字符串，后端把json字符串封装到user对象
System.out.println(user);
//做响应，模拟查询数据库
user.setUsername("LULU");
user.setAge(40);
//做响应
return user;
}
<!--传统方法文件上传的jar包-->
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.4</version>
</dependency>
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.6</version>
</dependency>
<form action="user/fileUpload1" method="post" enctype="multipart/form-data">
选择文件：<input type="file" name="upload" /><br/>
<input type="submit" value="上传"/>
</form>
@RequestMapping("/fileUpload1")
public String fileUpload1(HttpServletRequest request) throws Exception {
System.out.println("fileUpload1执行了……");
//使用fileupload组件完成文件上传
//上传的位置
String path = request.getSession().getServletContext().getRealPath("/uploads");
//判断，该路径是否存在
File file = new File(path);
if (!file.exists()){
//创建该文件夹
file.mkdirs();
}
//解析request对象，获取上传文件项
DiskFileItemFactory factory = new DiskFileItemFactory(); //磁盘文件
ServletFileUpload upload = new ServletFileUpload(factory);
//解析request
List<FileItem> items = upload.parseRequest(request);
//遍历
for (FileItem item: items) {
//进行判断，当前item对象是否是上传文件项
if (item.isFormField()){
//说明是普通表单项
}else{
//说明是上传文件项
//获取上传文件的名称
String filename = item.getName();
//把文件名称设置唯一值，uuid
String uuid = UUID.randomUUID().toString().replace("-", "");
filename = uuid + "_" + filename;
//完成上传文件
item.write(new File(path,filename));
//删除临时文件(>10kb会删掉，<10kb内存会保存临时文件，所以要删除掉)
item.delete();
}
}
return "success";
}
<!--配置文件解析器,id 必须为"multipartResolver"-->
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<!--文件最大大小-->
<property name="maxUploadSize" value="10485760"/>
</bean>
/**
* SpringMVC 文件上传
* @param request
* @return
* @throws Exception
*/
@RequestMapping("/fileUpload2")
public String fileUpload2(HttpServletRequest request, MultipartFile upload) throws IOException {
System.out.println("fileUpload2执行了……");
//上传的位置
String path = request.getSession().getServletContext().getRealPath("/uploads/");
//判断路径是否存在
File file = new File(path);
if (!file.exists()){
file.mkdirs();
}
//获取上传文件的名称
String filename = upload.getOriginalFilename();
//设置唯一值，uuid
String uuid = UUID.randomUUID().toString().replace("-","");
filename = uuid + "_" + filename;
//完成文件上传
upload.transferTo(new File(path,filename));
return "success";
}
springMVC 跨服务器方式文件上传
依赖注入：
<!--SpringMVC跨服务器方式上传文件依赖的包-->
<dependency>
<groupId>com.sun.jersey</groupId>
<artifactId>jersey-core</artifactId>
<version>1.18.1</version>
</dependency>
<dependency>
<groupId>com.sun.jersey</groupId>
<artifactId>jersey-client</artifactId>
<version>1.18.1</version>
</dependency>
后台控制：
/**
* 跨服务器文件上传
* @param upload
* @return
* @throws IOException
*/
@RequestMapping("/fileUpload3")
public String fileUpload3(MultipartFile upload) throws IOException {
System.out.println("fileUpload3执行了……");
//定义上传文件服务器路径
String path = "http://localhost:9990/uploads/";
//说明上传文件项
//获取上传文件的名称
String filename = upload.getOriginalFilename();
//设置唯一值，uuid
String uuid = UUID.randomUUID().toString().replace("-","");
filename = uuid + "_" + filename;
//完成文件上传，跨服务器文件上传
//1.创建客户端对象
Client client = Client.create();
//2.和图片服务器进行连接
WebResource webResource = client.resource(path + filename);
//3.上传文件
webResource.put(upload.getBytes());
return "success";
}
上传失败，出现错误HTTP Status 500 - Request processing failed; nested exception is com.sun.jersey.api.client.UniformInterfaceException: PUT http://localhost:9090/uploads/69f070620aa54e2f97a2c62299e02d14_1715-9.jpg returned a response status of 403 Forbidden
原因是跨服务器上传文件，但是文件不能写入，需要在 tomcat 目录下conf文件夹下的 web.xml 的<servlet> 配置中加入：
<init-param>
<param-name>readonly</param-name>
<param-value>false</param-value>
</init-param>
/**
* 自定义异常类
*/
public class SysException extends Exception {
//存储提示信息
private String message;
@Override
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public SysException(String message) {
this.message = message;
}
}
HandlerExceptionResolver/**
* 异常处理器
*/
public class SysExceptionResolver implements HandlerExceptionResolver {
/**
* 处理异常业务逻辑
* @param httpServletRequest
* @param httpServletResponse
* @param o
* @param e
* @return
*/
@Nullable
@Override
public ModelAndView resolveException(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, @Nullable Object o, Exception e) {
//获取异常对象
SysException sysException = null;
if (e instanceof SysException){
sysException = (SysException) e;
}else {
sysException = new SysException("系统正在维护……");
}
//创建ModelAndView 对象
ModelAndView mv = new ModelAndView();
mv.addObject("errorMsg",sysException.getMessage());
mv.setViewName("error");
return mv;
}
}
<!--配置异常处理器-->
<bean id="sysExceptionResolver" class="com.ssm.exception.SysExceptionResolver"/>
@RequestMapping("/testException")
public String testException() throws SysException {
System.out.println("testException执行了...");
try {
//模拟异常
int i = 10/0;
} catch (Exception e) {
//打印异常信息
e.printStackTrace();
//抛出自定义异常信息
throw new SysException("查询所有用户信息出错……");
}
return "success";
}
拦截器类似于Servlet 中的过滤器 Filter，用于对处理器进行预处理和后处理。
拦截器 & 过滤器
流程：
HandlerInterceptor 接口public class MyInterceptor implements HandlerInterceptor {
/**
* 预处理，controller方法执行前
* return true 放行，执行下一拦截器，如果没有，执行controller中的方法
* return false 不放行
* @param request
* @param response
* @param handler
* @return
* @throws Exception
*/
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
System.out.println("MyInterceptor执行了...");
return true;
}
/**
* 后处理方法
* @param request
* @param response
* @param handler
* @param modelAndView
* @throws Exception
*/
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable ModelAndView modelAndView) throws Exception {
System.out.println("MyInterceptor执行了...后");
// request.getRequestDispatcher("/WEB-INF/pages/error.jsp").forward(request,response);
}
/**
* success.jsp执行之后才会执行
* @param request
* @param response
* @param handler
* @param ex
* @throws Exception
*/
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable Exception ex) throws Exception {
System.out.println("MyInterceptor执行了...最后");
}
}
<mvc:interceptors>
<mvc:interceptor>
<!--要拦截的具体方法-->
<mvc:mapping path="/user/*"/>
<!--不要拦截的方法-->
<!--<mvc:exclude-mapping path=""/>-->
<!--配置拦截器对象-->
<bean class="com.ssm.interceptor.MyInterceptor"/>
</mvc:interceptor>
</mvc:interceptors>