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framework学习笔记day12---SpringMVC

2022-01-04 16:34:19  阅读：134  来源： 互联网

标签：String SpringMVC --- framework json user println new public


Restful风格介绍

  • WebAPI

    • 如果一个URL返回的不包含HTML，而是数据，那么这个URL就是一个WebAPI（web接 口）

  • Restful

    • 按照Rest风格访问WebAPI的一种方式

  • Restful风格

    • ①不同CRUD操作采用不同的请求方式
    • ②后台的响应数据采用JSON格式

HiddenHttpMethodFilter过滤器

  • 概述

    • form表单只支持get、post请求，如果要支持put、delete就需要使用HiddenHttpMethodFilter过滤器

  • 代码实现

    <!--post 2 put-->
<form th:action="@{/rest/post2Put}" method="post">
    <input type="hidden" name="_method" value="put">
    消息:<input type="text" name="msg"><br>
    <button type="submit">提交</button>
</form>

<!--post 2 delete-->
<form th:action="@{/rest/post2Delete}" method="post">
    <input type="hidden" name="_method" value="delete">
    消息:<input type="text" name="msg"><br>
    <button type="submit">提交</button>
</form>

    //@RequestMapping(path = "/rest/post2Put",method = RequestMethod.PUT)
@PutMapping("/rest/post2Put")
public String post2Put(String msg){
    System.out.println("msg = " + msg);
    return "demo01";
}

@DeleteMapping("/rest/post2Delete")
public String post2Delete(String msg){
    System.out.println("msg = " + msg);
    return "demo01";
}

  • 注意事项

    • 只能使用post模拟put、delete

Restful风格查询用户

  • 需求

    • 根据id查询用户记录

  • 分析

    http://localhost:8080/framework27/user/selectUserById?id=1 : 之前
http://localhost:8080/framework27/user/1 : 现在 , GET请求

  • 代码实现

    <a th:href="@{/user/1}">Restful风格查询用户</a>

    @GetMapping("/user/{userId}")
public String selectUserById(@PathVariable Integer userId){
    System.out.println("userId = " + userId);
    return "demo02";
}

Restful风格删除用户

  • 需求

    • 根据id删除用户记录

  • 分析

    http://localhost:8080/framework27/user/deleteUserById?id=1 : 之前
http://localhost:8080/framework27/user/1 : 现在 , DELETE请求

  • 代码实现

    @DeleteMapping("/user/{userId}")
public String deleteUserById(@PathVariable Integer userId){
    System.out.println("deleteUserById userId = " + userId);
    return "demo02";
}

    <body>


<div id="app">

    <!--post 2 delete-->
    <form method="post" id="deleteUserForm">
        <input type="hidden" name="_method" value="delete">

    </form>

    <a id="myA" th:href="@{/user/1}" @click.prevent="deleteUserById()">Restful风格删除用户</a>
</div>


</body>
<script th:src="@{/js/vue.js}"></script>
<script>


    //3,form表单根据a标签的href属性值发起请求
    var vue = new Vue({
        el: "#app",
        data: {},
        methods: {
            //1,点击a标签
            deleteUserById() {
                console.log("deleteUserById");
                //2,触发form表单
                var formEle = document.getElementById("deleteUserForm");
                var aEle = document.getElementById("myA");
                //3,form表单根据a标签的href属性值发起请求
                formEle.setAttribute("action", aEle.getAttribute("href"));
                formEle.submit();
            }
        }
    })


</script>

​

Restful风格添加用户

  • 需求

    • 添加用户记录

  • 分析

    http://localhost:8080/framework27/user/addUser?userName=root&userPwd=root : 之前 
http://localhost:8080/framework27/user?userName=root&userPwd=root: 现在 , POST请求

  • 代码实现

    @PostMapping("/user")
public String addUser(User inputUser){
    System.out.println("addUser user = " + inputUser);
    return "demo04";
}

    <form th:action="@{/user}" method="post" >
    <input type="text" name="userName" ><br>
    <input type="text" name="userPwd" ><br>
    <input type="submit" value="提交">
</form>

Restful风格登录功能

  • 需求

    • 登录功能

  • 分析

    http://localhost:8080/framework27/user/login?userName=root&userPwd=root : 之前,post
http://localhost:8080/framework27/user?userName=root&userPwd=root: 现在 , POST请求

  • 代码实现

    @PostMapping("/user/login")
public String login(User inputUser){
    System.out.println("login user = " + inputUser);
    return "demo05";
}

    <form th:action="@{/user/login}" method="post" >
    <input type="text" name="userName" ><br>
    <input type="text" name="userPwd" ><br>
    <input type="submit" value="提交">
</form>

​

Restful风格修改用户功能

  • 需求

    • 根据id修改用户记录

  • 分析

    http://localhost:8080/framework27/user/updateUserById?userId=1&userName=root&userPwd=root : 之前,post
http://localhost:8080/framework27/user?userId=1&userName=root&userPwd=root : 现在 , PUT请求

  • 代码实现

    @PutMapping("/user")
public String updateUserById(User inputUser){
    System.out.println("updateUserById user = " + inputUser);
    return "demo04";
}

    <form th:action="@{/user}" method="post" >
    <input type="hidden" name="_method" value="put">
    <input type="hidden" name="userId" value="250">
    <input type="text" name="userName" ><br>
    <input type="text" name="userPwd" ><br>
    <input type="submit" value="提交">
</form>

​

SpringMVC获取AJAX发送的普通参数

  • 代码实现

    <body>
<div id="app">
    <form th:action="@{/ajax/getParamter}" method="post" @submit.prevent="getParamter()">

        <input type="text" name="userName" v-model="user.userName"><br>
        <input type="text" name="userPwd" v-model="user.userPwd"><br>
        <input type="submit" value="提交">
    </form>
</div>

</body>
<script th:src="@{/js/axios.js}"></script>
<script th:src="@{/js/vue.js}"></script>
<script>

    var vue = new Vue({
        el: "#app",
        data: {
            user: {
                userId: 500,
                userName: "",
                userPwd: ""
            }
        },
        methods: {
            getParamter() {
                var _this = this;
                //发起异步请求 /ajax/getParamter
                axios({
                    method: "get",
                    url: "/framework27/ajax/getParamter",
                    params: {
                        userId: _this.user.userId,
                        userName: _this.user.userName,
                        userPwd: _this.user.userPwd
                    }
                }).then(function (res) {
                    var data = res.data;
                    console.log(data);

                })
            }
        }
    })

</script>

    @RequestMapping("/ajax/getParamter")
public void getParamter(User user, HttpServletResponse response) throws IOException {
    System.out.println("user = " + user);
    ResultVO resultVO = new ResultVO(true, "操作成功!", null);
    //resultVO 2 json字符串
    response.setContentType("application/json;charset=utf-8");
    String jsonStr = new ObjectMapper().writeValueAsString(resultVO);
    response.getWriter().write(jsonStr);
}

SpringMVC获取AJAX发送的请求体json

  • 代码实现1

    <body>
<div id="app">
    <form th:action="@{/ajax/getParamter}" method="post" @submit.prevent="getParamter()">
        <!--<input type="hidden" name="userId" value="250" v-model="user.userId">-->
        <input type="text" name="userName" v-model="user.userName"><br>
        <input type="text" name="userPwd" v-model="user.userPwd"><br>
        <input type="submit" value="提交">
    </form>
</div>

</body>
<script th:src="@{/js/axios.js}"></script>
<script th:src="@{/js/vue.js}"></script>
<script>

    var vue = new Vue({
        el: "#app",
        data: {
            user: {
                userId: 500,
                userName: "",
                userPwd: ""
            }
        },
        methods: {
            getParamter() {
                var _this = this;
                //发起异步请求 /ajax/getParamter
                axios({
                    method: "post",
                    url: "/framework27/ajax/getParamter2",
                    data: {
                        userId: _this.user.userId,
                        userName: _this.user.userName,
                        userPwd: _this.user.userPwd
                    }
                }).then(function (res) {
                    console.log(res);
                })
            }
        }
    })

</script>

    @RequestMapping("/ajax/getParamter2")
public void getParamter2(HttpServletRequest request, HttpServletResponse response) throws IOException {
    //①读取请求正文json
    BufferedReader bufferedReader = request.getReader();
    String content = null;
    StringBuffer sb = new StringBuffer();
    while ((content = bufferedReader.readLine()) != null) {
        sb.append(content);
    }
    String inputJsonStr = sb.toString();
    //②jsonStr 2 javabean
    User user = new ObjectMapper().readValue(inputJsonStr, User.class);
    System.out.println("user = " + user);

    ResultVO resultVO = new ResultVO(true, "操作成功!", null);
    //resultVO 2 json字符串
    response.setContentType("application/json;charset=utf-8");
    String jsonStr = new ObjectMapper().writeValueAsString(resultVO);
    response.getWriter().write(jsonStr);
}

  • 代码实现2

    @RequestMapping("/ajax/getParamter3")
public void getParamter3(@RequestBody String inputJsonStr, HttpServletResponse response) throws IOException {
    //①读取请求正文json
    System.out.println("inputJsonStr = " + inputJsonStr);
    //② jsonStr2 javabean
    User user = new ObjectMapper().readValue(inputJsonStr, User.class);
    System.out.println("user = " + user);

    ResultVO resultVO = new ResultVO(true, "操作成功!", null);
    //resultVO 2 json字符串
    response.setContentType("application/json;charset=utf-8");
    String jsonStr = new ObjectMapper().writeValueAsString(resultVO);
    response.getWriter().write(jsonStr);
}

  • 代码实现3(推荐)

    @RequestMapping("/ajax/getParamter4")
public void getParamter4(@RequestBody User user, HttpServletResponse response) throws IOException {
    //①读取请求正文json
    //②jsonStr 2 javabean
    System.out.println("user = " + user);

    ResultVO resultVO = new ResultVO(true, "操作成功!", null);
    //resultVO 2 json字符串
    response.setContentType("application/json;charset=utf-8");
    String jsonStr = new ObjectMapper().writeValueAsString(resultVO);
    response.getWriter().write(jsonStr);
}

SpringMVC响应json字符串

  • 概述

    • @ResponseBody : 将Handler方法的返回值作为响应正文返回给浏览器；如果返回值是一个javabean对象会自动将其转换为json字符串；同时也解决响应正文中文乱码问题。

  • 代码实现1

    @RequestMapping("/ajax/testResponse1")
public void testResponse1(@RequestBody User user, HttpServletResponse response) throws IOException {
    //①读取请求正文json
    //②jsonStr 2 javabean
    System.out.println("user = " + user);

    response.setContentType("application/json;charset=utf-8");
    ResultVO resultVO = new ResultVO(true, "操作成功!", null);
    //① resultVO 2 json字符串
    String jsonStr = new ObjectMapper().writeValueAsString(resultVO);
    //② json字符串作为响应正文返回给客户端
    response.getWriter().write(jsonStr);
}

  • 代码实现2

    @ResponseBody
@RequestMapping("/ajax/testResponse2")
public String testResponse2(@RequestBody User user, HttpServletResponse response) throws IOException {
    //①读取请求正文json
    //②jsonStr 2 javabean
    System.out.println("user = " + user);

    ResultVO resultVO = new ResultVO(true, "操作成功!", null);
    //① resultVO 2 json字符串
    String jsonStr = new ObjectMapper().writeValueAsString(resultVO);
    //② json字符串作为响应正文返回给客户端
    return jsonStr;//以前，默认应该是逻辑视图名称；返回是一个json字符串并且是响应正文。
}

  • 代码实现3(推荐)

    @ResponseBody
@RequestMapping("/ajax/testResponse3")
public ResultVO testResponse3(@RequestBody User user, HttpServletResponse response) throws IOException {
    //①读取请求正文json
    //②jsonStr 2 javabean
    System.out.println("user = " + user);
    return new ResultVO(true, "操作成功!", null);//以前，默认应该是逻辑视图名称；返回是一个json字符串并且是响应正文。
}

异常映射概述

  • 概述
    • 一个项目中会包含很多个模块，各个模块需要分工完成。如果张三负责的模块按照 A 方案处 理异常，李四负责的模块按照 B 方法处理异常……各个模块处理异常的思路、代码、命名细 节都不一样，那么就会让整个项目非常混乱。
    • 将异常类型和某个具体的视图关联起来，建立映射关系。可以通过 SpringMVC 框架来帮助 我们管理异常。
  • 好处
    • 让异常控制和核心业务解耦，二者各自维护，结构性更好
    • 整个项目层面使用同一套规则来管理异常

注解开发异常处理器

  • 以前

    @RequestMapping("/exception/testException1")
public String testException1(int num) {
    try {
        if (num == 1) {
            String str = null;
            System.out.println(str.length());

        } else if (num == 2) {
            System.out.println(1 / 0);
        }
    } catch (NullPointerException e) {
        e.printStackTrace();
        return "error1";
    } catch (ArithmeticException e) {
        e.printStackTrace();
        return "error2";
    }
    return "index";
}

  • 现在

    @RequestMapping("/exception/testException2")
public String testException2(int num) {
    if (num == 1) {
        String str = null;
        System.out.println(str.length());
    } else if (num == 2) {
        System.out.println(1 / 0);
    }
    return "index";
}

    @ControllerAdvice
public class MyExceptionAdvice {


    @ExceptionHandler(NullPointerException.class)
    public String handleNullPointerException(){
        System.out.println("MyExceptionAdvice handleNullPointerException");
        return "error1";
    }

    @ExceptionHandler(ArithmeticException.class)
    public String handleArithmeticException(){
        System.out.println("MyExceptionAdvice handleArithmeticException");
        return "error2";
    }


}

异常处理解决方案

  • 代码实现

    @ResponseBody
@RequestMapping("/exception/testException3")
public ResultVO testException3(int num) {
    try {
        if (num == 1) {
            String str = null;
            System.out.println(str.length());
        } else if (num == 2) {
            System.out.println(1 / 0);
        } else if (num == 3) {
            //业务异常 (用户输入有问题) ，比如：输入为空、格式不对...
            throw new MyBusinessException("你老实点~~~");
        }
    } catch (ArithmeticException e) {
        e.printStackTrace();
        throw new MySystemException("系统异常！");
    } catch (NullPointerException e) {
        e.printStackTrace();
        throw new MySystemException("系统异常！");
    }
    return new ResultVO(true, "操作成功!", null);
}

    @ControllerAdvice
public class MyExceptionAdvice {

    @ResponseBody
    @ExceptionHandler(MyBusinessException.class)
    public ResultVO handleBusinessException(Exception e) {
        //提示用户
        return new ResultVO(false, "操作失败!", e.getMessage());
    }


    @ResponseBody
    @ExceptionHandler(MySystemException.class)
    public ResultVO handleSystemException(Exception e) {
        //安抚用户

        //发送消息给开发人员

        //记录日志
        return new ResultVO(false, "操作失败!", e);
    }

}

​

Spring、MyBatis、SpringMVC整合

  • 开发步骤

    • ①引入相关依赖

    • ②Spring+MyBatis (mapper接口代理)

      • 1.1,定义service接口及其实现子类
      • 1.2,定义mapper接口
      • 1.3,编写spring-core.xml
        • 扫描注解
        • 扫描所有的mapper接口代理对象
        • 配置SqlSessionFactoryBean
        • 配置DruidDataSource
      • 1.4,测试通过

    • ③整合SpringMVC

      • 方式一,编写web.xml
        • 配置DispatcherServlet
          • 加载spring-mvc.xml
        • 配置ContextLoaderListener
          • 加载spring-core.xml
      • 方式二,编写web.xml
        • 配置DispatcherServlet
          • 加载spring-mvc.xml
          • 加载spring-core.xml

    • ③整合SpringMVC

      <!--方式一-->
<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:spring-core.xml</param-value>
</context-param>

<listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>


<servlet>
    <servlet-name>mvc</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:spring-mvc.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
    <servlet-name>mvc</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>

      <!--方式二-->
<servlet>
    <servlet-name>mvc</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:spring-*.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
    <servlet-name>mvc</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>

​

标签：String,SpringMVC,---,framework,json,user,println,new,public
来源： https://blog.csdn.net/Wynb1020/article/details/122305589

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