Spring 注解面面通之 @PathVariable_综合

??@PathVariable用于将请求URI模板变量映射到控制器处理方法的参数中。

??注解解析

??① value：

????绑定的参数名称，参数值为String类型。

??② name：

????绑定的参数名称，参数值为String类型。name和value可以同时使用，但两者的值需一致，否则会出现错误。

attribute 'name' and its alias 'value' are present with values of [XXX] and [XXX], but only one is permitted
1

??③ required：

????URI中是否必须包含指定的值，默认值为true。

????required为true时，如果URI中缺少指定的值，则会抛出异常。

????required为false时，如果URI中缺少指定的值，则会返回null。

??注解示例

??1) 建Controller，用来演示@PathVariable使用方法。

package com.arhorchin.securitit.webannotations;import java.util.Map;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.servlet.ModelAndView;import com.alibaba.fastjson.JSON;/*** @author Securitit.* @note 演示@SessionAttribute使用方法.*/
@Controller
@RequestMapping("/WebAnnotations")
public class PathVariableController {
    /*** logger.*/private Logger logger = LoggerFactory.getLogger(PathVariableController.class);/*** 跳转页面.*/@RequestMapping(value = "/PathVariable.html",method = RequestMethod.GET)public ModelAndView pathVariableHtml(HttpServletRequest req, HttpServletResponse res, ModelMap modelMap)throws Exception {
    return new ModelAndView("webannotations/PathVariable", modelMap);}/*** 从请求路径中以Map解析方法参数.*/@ResponseBody@RequestMapping(value = "/{Province}/{City}/PathVariableMap.do",method = RequestMethod.GET)public String pathVariableMap(@PathVariable Map<String, String> pathVariableMap) throws Exception {
    logger.info("Current value of PathVariable is " + JSON.toJSONString(pathVariableMap));return "Current value of PathVariable is " + JSON.toJSONString(pathVariableMap);}/*** 从请求路径中以单键值形式解析方法参数.*/@ResponseBody@RequestMapping(value = "/{Province}/{City}/PathVariableSingle.do",method = RequestMethod.GET)public String PathVariableSingle(@PathVariable("Province") String province, @PathVariable("City") String city)throws Exception {
    logger.info("Current value of PathVariable [Province] is " + province + " | [City] is " + city);return "Current value of PathVariable [Province] is " + province + " | [City] is " + city;}/*** 从请求路径中以单键值形式解析方法参数.*/@ResponseBody@RequestMapping(value = {
     "/{Province}/{City}/PathVariableSingleRequiredTrue.do", "/PathVariableSingleRequiredTrue.do" },method = RequestMethod.GET)public String PathVariableSingleRequiredTrue(@PathVariable(value = "Province",required = true) String province,@PathVariable(value = "City",required = true) String city)throws Exception {
    logger.info("Current value of PathVariable(required = true) [Province] is " + province + " | [City] is " + city);return "Current value of PathVariable(required = true) [Province] is " + province + " | [City] is " + city;}/*** 从请求路径中以单键值形式解析方法参数.*/@ResponseBody@RequestMapping(value = {
     "/{Province}/{City}/PathVariableSingleRequiredFalse.do", "/PathVariableSingleRequiredFalse.do" },method = RequestMethod.GET)public String PathVariableSingleRequiredFalse(@PathVariable(value = "Province",required = false) String province,@PathVariable(value = "City",required = false) String city)throws Exception {
    logger.info("Current value of PathVariable(required = false) [Province] is " + province + " | [City] is " + city);return "Current value of PathVariable(required = false) [Province] is " + province + " | [City] is " + city;}}

??2) 建html，用来演示PathVariableController示例。

<!doctype html>
<html lang="en"><head><meta charset="UTF-8"><meta name="Author" content="Securitit"><meta name="Keywords" content="-"><meta name="Description" content="Securitit @PathVariable 测试页面"><title>@PathVariable 测试页面</title></head><body><a href="http://localhost:9199/spring-annotations/WebAnnotations/LiNing/DaLian/PathVariableMap.do" target="_blank">点击链接，@PathVariable进行参数绑定，后端以Map解析方法参数.</a><br /><br /><a href="http://localhost:9199/spring-annotations/WebAnnotations/LiNing/DaLian/PathVariableSingle.do" target="_blank">点击链接，@PathVariable进行参数绑定，以单键值形式解析方法参数.</a><br /><br /><a href="http://localhost:9199/spring-annotations/WebAnnotations/PathVariableSingleRequiredTrue.do" target="_blank">点击链接，@PathVariable进行参数绑定，以单键值形式解析方法参数.required=true，未传值时抛出异常.</a><br /><br /><a href="http://localhost:9199/spring-annotations/WebAnnotations/PathVariableSingleRequiredFalse.do" target="_blank">点击链接，@PathVariable进行参数绑定，以单键值形式解析方法参数.required=false，未传值时返回null.</a></body>
</html>