SSM(SpringMVC)

SpringMVC概述

将后端服务器Servlet拆分成三层，分别是web、service和dao

• web层主要由servlet来处理，负责页面请求和数据的收集以及响应结果给前端
• service层主要负责业务逻辑的处理
• dao层主要负责数据的增删改查操作

针对web层进行了优化，采用了MVC设计模式，将其设计为controller、view和Model

• controller负责请求和数据的接收，接收后将其转发给service进行业务处理
• service根据需要会调用dao对数据进行增删改查
• dao把数据处理完后将结果交给service,service再交给controller
• controller根据需求组装成Model和View,Model和View组合起来生成页面转发给前端浏览器

• 这样做的好处就是controller可以处理多个请求，并对请求进行分发，执行不同的业务操作。

  
  
  image.png

SpringMVC主要负责的就是

• controller如何接收请求和数据
• 如何将请求和数据转发给业务层
• 如何将响应数据转换成json发回到前端

SpringMVC入门案例

SpringMVC的制作过程和上述流程几乎是一致的，具体的实现流程是什么?
1.创建web工程(Maven结构)
2.设置tomcat服务器，加载web工程(tomcat插件)
3.导入坐标(SpringMVC+Servlet)
4.定义处理请求的功能类(UserController)
5.设置请求映射(配置映射关系)
6.将SpringMVC设定加载到Tomcat容器中

案例制作

创建Maven项目

image.png

导入jar包

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.itheima</groupId>
  <artifactId>springmvc_01_quickstart</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <dependencies>
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>3.1.0</version>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>5.2.10.RELEASE</version>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.tomcat.maven</groupId>
        <artifactId>tomcat7-maven-plugin</artifactId>
        <version>2.1</version>
        <configuration>
          <port>80</port>
          <path>/</path>
        </configuration>
      </plugin>
    </plugins>
  </build>


</project>

创建配置类

@Configuration
@ComponentScan("com.itheima.controller")
public class SpringMvcConfig {
}

创建Controller类

@Controller
public class UserController {

    //设置映射路径为/save，即外部访问路径
    @RequestMapping("/save")
    //设置当前操作返回结果为指定json数据（本质上是一个字符串信息）
    @ResponseBody
    public String save(){
        System.out.println("user save ...");
        return "{'info':'springmvc'}";
    }

    //设置映射路径为/delete，即外部访问路径
    @RequestMapping("/delete")
    @ResponseBody
    public String delete(){
        System.out.println("user save ...");
        return "{'info':'springmvc'}";
    }
}

使用配置类替换web.xml

public class ServletContainersInitConfig extends AbstractDispatcherServletInitializer {
    //加载springmvc配置类，产生springmvc容器（本质还是spring容器）
    protected WebApplicationContext createServletApplicationContext() {
        //初始化WebApplicationContext对象
        AnnotationConfigWebApplicationContext ctx = new AnnotationConfigWebApplicationContext();
        //加载指定配置类
        ctx.register(SpringMvcConfig.class);
        return ctx;
    }

    //设置由springmvc控制器处理的请求映射路径
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }

    //加载spring配置类
    protected WebApplicationContext createRootApplicationContext() {
        return null;
    }
}

配置Tomcat环境

image.png

bean加载控制

因为功能不同，如何避免Spring错误加载到SpringMVC的bean?

• 方式一:Spring加载的bean设定扫描范围为精准范围，例如service包、dao包等
• 方式二:Spring加载的bean设定扫描范围为com.itheima,排除掉controller包中的bean
• 方式三:不区分Spring与SpringMVC的环境，加载到同一个环境中[了解即可]

设置bean加载控制

• 方式一:修改Spring配置类，设定扫描范围为精准范围。

@ComponentScan({"com.itheima.service","com.itheima.dao"})

方式二:修改Spring配置类，设定扫描范围为com.itheima,排除掉controller包中的bean

@Configuration
@ComponentScan(value="com.itheima",
    excludeFilters=@ComponentScan.Filter(
   type = FilterType.ANNOTATION,
        classes = Controller.class
   )
)
public class SpringConfig {
}

• excludeFilters属性：设置扫描加载bean时，排除的过滤规则
• type属性：设置排除规则，当前使用按照bean定义时的注解类型进行排除
  ANNOTATION：按照注解排除
  ASSIGNABLE_TYPE:按照指定的类型过滤
  ASPECTJ:按照Aspectj表达式排除，基本上不会用
  REGEX:按照正则表达式排除
  CUSTOM:按照自定义规则排除
• classes属性：设置排除的具体注解类，当前设置排除@Controller定义的bean

有了Spring的配置类，要想在tomcat服务器启动将其加载，我们需要修改ServletContainersInitConfig

public class ServletContainersInitConfig extends 
AbstractDispatcherServletInitializer {
    protected WebApplicationContext createServletApplicationContext() {
        AnnotationConfigWebApplicationContext ctx = new 
AnnotationConfigWebApplicationContext();
        ctx.register(SpringMvcConfig.class);
        return ctx;
   }
    protected String[] getServletMappings() {
        return new String[]{"/"};
   }
    protected WebApplicationContext createRootApplicationContext() {
      AnnotationConfigWebApplicationContext ctx = new 
AnnotationConfigWebApplicationContext();
        ctx.register(SpringConfig.class);
        return ctx;
   }
}

对于上述的配置方式，Spring还提供了一种更简单的配置方式，可以不用再去创建AnnotationConfigWebApplicationContext对象，不用手register对应的配置类.

public class ServletContainersInitConfig extends 
AbstractAnnotationConfigDispatcherServletInitializer {
 
    protected Class<?>[] getRootConfigClasses() {
        return new Class[]{SpringConfig.class};
}
 
    protected Class<?>[] getServletConfigClasses() {
        return new Class[]{SpringMvcConfig.class};
   }
 
    protected String[] getServletMappings() {
        return new String[]{"/"};
   }
}

设置请求映射路径

• 修改Controller

@Controller
public class UserController {
 
    @RequestMapping("/user/save")
    @ResponseBody
    public String save(){
        System.out.println("user save ...");
        return "{'module':'user save'}";
   }
    
    @RequestMapping("/user/delete")
    @ResponseBody
    public String save(){
        System.out.println("user delete ...");
        return "{'module':'user delete'}";
   }
}
 
@Controller
public class BookController {
 
    @RequestMapping("/book/save")
    @ResponseBody
    public String save(){
        System.out.println("book save ...");
        return "{'module':'book save'}";
   }
}

优化路径配置

@Controller
@RequestMapping("/user")
public class UserController {
 
    @RequestMapping("/save")
    @ResponseBody
    public String save(){
        System.out.println("user save ...");
        return "{'module':'user save'}";
   }
    
    @RequestMapping("/delete")
    @ResponseBody
public String save(){
        System.out.println("user delete ...");
        return "{'module':'user delete'}";
   }
}
 
@Controller
@RequestMapping("/book")
public class BookController {
 
    @RequestMapping("/save")
    @ResponseBody
    public String save(){
        System.out.println("book save ...");
        return "{'module':'book save'}";
   }
}

请求参数

关于请求参数的传递与接收是和请求方式有关系的，目前比较常见的两种请求方式为：

• GET
• POST

http://localhost/commonParam?name=itcast

image.png

接收参数：

@Controller
public class UserController {
 
    @RequestMapping("/commonParam")
    @ResponseBody
    public String commonParam(String name){
        System.out.println("普通参数传递 name ==> "+name);
        return "{'module':'commonParam'}";
   }
}

GET发送多个参数

http://localhost/commonParam?name=itcast&age=15

image.png

接收参数：

@Controller
public class UserController {
 
    @RequestMapping("/commonParam")
    @ResponseBody
    public String commonParam(String name,int age){
        System.out.println("普通参数传递 name ==> "+name);
        System.out.println("普通参数传递 age ==> "+age);
        return "{'module':'commonParam'}";
   }
}

GET请求中文乱码

• 如果我们传递的参数中有中文，你会发现接收到的参数会出现中文乱码问题。
• 发送请求: http://localhost/commonParam?name=张三&age=18
  
  image.png

<build>
    <plugins>
      <plugin>
<groupId>org.apache.tomcat.maven</groupId>
        <artifactId>tomcat7-maven-plugin</artifactId>
        <version>2.1</version>
        <configuration>
          <port>80</port><!--tomcat端口号-->
          <path>/</path> <!--虚拟目录-->
          <uriEncoding>UTF-8</uriEncoding><!--访问路径编解码字符集-->
        </configuration>
      </plugin>
    </plugins>
  </build>

POST发送参数

• 发送请求与参数:

  
  
  image.png
• 接收参数：
  和GET一致，不用做任何修改

@Controller
public class UserController {
 
    @RequestMapping("/commonParam")
    @ResponseBody
    public String commonParam(String name,int age){
        System.out.println("普通参数传递 name ==> "+name);
        System.out.println("普通参数传递 age ==> "+age);
        return "{'module':'commonParam'}";
   }
}

POST请求中文乱码

image.png

控制台打印，会发现有中文乱码问题。

public class ServletContainersInitConfig extends 
AbstractAnnotationConfigDispatcherServletInitializer {
    protected Class<?>[] getRootConfigClasses() {
        return new Class[0];
   }
 
    protected Class<?>[] getServletConfigClasses() {
        return new Class[]{SpringMvcConfig.class};
   }
 
    protected String[] getServletMappings() {
        return new String[]{"/"};
   }
 
    //乱码处理
    @Override
    protected Filter[] getServletFilters() {
        CharacterEncodingFilter filter = new CharacterEncodingFilter();
        filter.setEncoding("UTF-8");
        return new Filter[]{filter};
   }
}

五种类型参数传递

普通参数

• 普通参数:url地址传参，地址参数名与形参变量名相同，定义形参即可接收参数。

  
  
  image.png

如果形参与地址参数名不一致该如何解决

• 发送请求与参数:

http://localhost/commonParamDifferentName?name=张三&age=18

• 后台接收参数:

@RequestMapping("/commonParamDifferentName")
@ResponseBody
public String commonParamDifferentName(String userName , int age){
    System.out.println("普通参数传递 userName ==> "+userName);
    System.out.println("普通参数传递 age ==> "+age);
    return "{'module':'common param different name'}";
}

• 因为前端给的是name ,后台接收使用的是userName ,两个名称对不上，导致接收数据失败:
• 解决方案:使用@RequestParam注解

@RequestMapping("/commonParamDifferentName")
    @ResponseBody
    public String commonParamDifferentName(@RequestPaam("name") String 
userName , int age){
        System.out.println("普通参数传递 userName ==> "+userName);
        System.out.println("普通参数传递 age ==> "+age);
        return "{'module':'common param different name'}";
   }

POJO类型参数

• POJO参数：请求参数名与形参对象属性名相同，定义POJO类型形参即可####接收参数

public class User {
    private String name;
    private int age;
    //setter...getter...略
}

image.png

后台接收参数:

//POJO参数：请求参数与形参对象中的属性对应即可完成参数传递
@RequestMapping("/pojoParam")
@ResponseBody
public String pojoParam(User user){
    System.out.println("pojo参数传递 user ==> "+user);
    return "{'module':'pojo param'}";
}

请求参数key的名称要和POJO中属性的名称一致，否则无法封装。

嵌套POJO类型参数

• 如果POJO对象中嵌套了其他的POJO类

public class Address {
    private String province;
    private String city;
    //setter...getter...略
}
public class User {
    private String name;
    private int age;
    private Address address;
    //setter...getter...略
}

• 发送请求和参数:

image.png

• 后台接收参数:

//POJO参数：请求参数与形参对象中的属性对应即可完成参数传递
@RequestMapping("/pojoParam")
@ResponseBody
public String pojoParam(User user){
    System.out.println("pojo参数传递 user ==> "+user);
    return "{'module':'pojo param'}";
}

请求参数key的名称要和POJO中属性的名称一致，否则无法封装

数组类型参数

数组类型参数

• 发送请求和参数

  
  
  image.png
• 后台接收参数:

//数组参数：同名请求参数可以直接映射到对应名称的形参数组对象中
    @RequestMapping("/arrayParam")
    @ResponseBody
    public String arrayParam(String[] likes){
        System.out.println("数组参数传递 likes ==> "+ Arrays.toString(likes));
        return "{'module':'array param'}";
   }

集合类型参数

image.png

• 后台接收参数:
• 使用@RequestParam注解

//集合参数：同名请求参数可以使用@RequestParam注解映射到对应名称的集合对象中作为数据
@RequestMapping("/listParam")
@ResponseBody
public String listParam(@RequestParam List<String> likes){
    System.out.println("集合参数传递 likes ==> "+ likes);
    return "{'module':'list param'}";
}

JSON数据传输参数

对于JSON数据类型，我们常见的有三种:

• json普通数组（["value1","value2","value3",...]）
• json对象（{key1:value1,key2:value2,...}）
• json对象数组（[{key1:value1,...},{key2:value2,...}]）

JSON普通数组

pom.xml添加依赖

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.9.0</version>
</dependency>

PostMan发送JSON数据

image.png

开启SpringMVC注解支持

• 在SpringMVC的配置类中开启SpringMVC的注解支持，这里面就包含了将JSON转换成对象的功能。

@Configuration
@ComponentScan("com.itheima.controller")
//开启json数据类型自动转换
@EnableWebMvc
public class SpringMvcConfig {
}

参数前添加@RequestBody

//使用@RequestBody注解将外部传递的json数组数据映射到形参的集合对象中作为数据
@RequestMapping("/listParamForJson")
@ResponseBody
public String listParamForJson(@RequestBody List<String> likes){
    System.out.println("list common(json)参数传递 list ==> "+likes);
    return "{'module':'list common for json param'}";
}

JSON对象数据

• 请求和数据的发送:

{
 "name":"itcast",
 "age":15
}

• 后端接收数据：

@RequestMapping("/pojoParamForJson")
@ResponseBody
public String pojoParamForJson(@RequestBody User user){
    System.out.println("pojo(json)参数传递 user ==> "+user);
    return "{'module':'pojo for json param'}";
}

• 如果想要address也有数据，我们需求修改前端传递的数据内容:

{
 "name":"itcast",
 "age":15,
    "address":{
        "province":"beijing",
        "city":"beijing"
   }
}

JSON对象数组

• 请求和数据的发送:

[
   {"name":"itcast","age":15},
   {"name":"itheima","age":12}
]

• 后端接收数据:

@RequestMapping("/listPojoParamForJson")
@ResponseBody
public String listPojoParamForJson(@RequestBody List<User> list){
    System.out.println("list pojo(json)参数传递 list ==> "+list);
    return "{'module':'list pojo for json param'}";
}

日期类型参数传递

编写方法接收日期数据

• 在UserController类中添加方法，把参数设置为日期类型

@RequestMapping("/dataParam")
@ResponseBody
public String dataParam(Date date)
    System.out.println("参数传递 date ==> "+date);
    return "{'module':'data param'}";
}

启动Tomcat服务器

• 查看控制台是否报错，如果有错误，先解决错误。

使用PostMan发送请求

• 使用PostMan发送GET请求，并设置date参数
• http://localhost/dataParam?date=2088/08/08

更换日期格式

@RequestMapping("/dataParam")
@ResponseBody
public String dataParam(Date date,
                        @DateTimeFormat(pattern="yyyy-MM-dd") Date date1)
    System.out.println("参数传递 date ==> "+date);
 System.out.println("参数传递 date1(yyyy-MM-dd) ==> "+date1);
    return "{'module':'data param'}";
}

携带时间的日期

@RequestMapping("/dataParam")
@ResponseBody
public String dataParam(Date date,
                        @DateTimeFormat(pattern="yyyy-MM-dd") Date date1,
                        @DateTimeFormat(pattern="yyyy/MM/dd HH:mm:ss") Date 
date2)
    System.out.println("参数传递 date ==> "+date);
 System.out.println("参数传递 date1(yyyy-MM-dd) ==> "+date1);
 System.out.println("参数传递 date2(yyyy/MM/dd HH:mm:ss) ==> "+date2);
    return "{'module':'data param'}";
}

响应

响应页面[了解]

设置返回页面

@Controller
public class UserController {
    
    @RequestMapping("/toJumpPage")
    //注意
    //1.此处不能添加@ResponseBody,如果加了该注入，会直接将page.jsp当字符串返回前端
    //2.方法需要返回String
    public String toJumpPage(){
        System.out.println("跳转页面");
        return "page.jsp";
   }
    
}

返回文本数据[了解]

设置返回文本内容

@Controller
public class UserController {
    
   @RequestMapping("/toText")
 //注意此处该注解就不能省略，如果省略了,会把response text当前页面名称去查找，如果没有
回报404错误
    @ResponseBody
    public String toText(){
        System.out.println("返回纯文本数据");
        return "response text";
   }
    
}

响应JSON数据

• 响应POJO对象

@Controller
public class UserController {
    
    @RequestMapping("/toJsonPOJO")
    @ResponseBody
    public User toJsonPOJO(){
        System.out.println("返回json对象数据");
        User user = new User();
        user.setName("itcast");
        user.setAge(15);
        return user;
   }
    
}

REST简介

• 传统风格资源描述形式
  http://localhost/user/getById?id=1 查询id为1的用户信息
  http://localhost/user/saveUser 保存用户信息

• REST风格描述形式
  http://localhost/user/1
  http://localhost/user

• 按照REST风格访问资源时使用行为动作区分对资源进行了何种操作
  http://localhost/users 查询全部用户信息 GET（查询）
  http://localhost/users/1 查询指定用户信息 GET（查询）
  http://localhost/users 添加用户信息 POST（新增/保存）
  http://localhost/users 修改用户信息 PUT（修改/更新）
  http://localhost/users/1 删除用户信息 DELETE（删除）

RESTful入门案例

修改RESTful风格

• 新增

@Controller
public class UserController {
 //设置当前请求方法为POST，表示REST风格中的添加操作
    @RequestMapping(value = "/users",method = RequestMethod.POST)
    @ResponseBody
    public String save() {
        System.out.println("user save...");
        return "{'module':'user save'}";
   }
}

• 删除

@Controller
public class UserController {
    //设置当前请求方法为DELETE，表示REST风格中的删除操作
 @RequestMapping(value = "/users",method = RequestMethod.DELETE)
    @ResponseBody
    public String delete(Integer id) {
        System.out.println("user delete..." + id);
        return "{'module':'user delete'}";
   }
}

传递路径参数

• 前端发送请求的时候使用: http://localhost/users/1 ,路径中的1就是我们想要传递的参数。
• 后端获取参数，需要做如下修改:
  修改@RequestMapping的value属性，将其中修改为/users/{id}，目的是和路径匹配在方法的形参前添加@PathVariable注解

@Controller
public class UserController {
    //设置当前请求方法为DELETE，表示REST风格中的删除操作
 @RequestMapping(value = "/users/{id}",method = RequestMethod.DELETE)
    @ResponseBody
    public String delete(@PathVariable Integer id) {
        System.out.println("user delete..." + id);
        return "{'module':'user delete'}";
   }
}

• 如果方法形参的名称和路径{}中的值不一致

  
  
  image.png

如果有多个参数需要传递该如何编写

• 前端发送请求的时候使用: http://localhost/users/1/tom ,路径中的1和tom就是我们想要传递的两个参数。

@Controller
public class UserController {
    //设置当前请求方法为DELETE，表示REST风格中的删除操作
 @RequestMapping(value = "/users/{id}/{name}",method = 
RequestMethod.DELETE)
    @ResponseBody
    public String delete(@PathVariable Integer id,@PathVariable String name) 
{
        System.out.println("user delete..." + id+","+name);
        return "{'module':'user delete'}";
   }
}

• 修改

@Controller
public class UserController {
    //设置当前请求方法为PUT，表示REST风格中的修改操作
    @RequestMapping(value = "/users",method = RequestMethod.PUT)
    @ResponseBody
    public String update(@RequestBody User user) {
        System.out.println("user update..." + user);
        return "{'module':'user update'}";
   }
}

• 查询所有

@Controller
public class UserController {
    //设置当前请求方法为GET，表示REST风格中的查询操作
    @RequestMapping(value = "/users" ,method = RequestMethod.GET)
    @ResponseBody
    public String getAll() {
        System.out.println("user getAll...");
        return "{'module':'user getAll'}";
   }
}

RESTful快速开发

• 问题1：每个方法的@RequestMapping注解中都定义了访问路径/books，重复性太高。
  将@RequestMapping提到类上面，用来定义所有方法共同的访问路径。
• 问题2：每个方法的@RequestMapping注解中都要使用method属性定义请求方式，重复性太高。
  使用@GetMapping @PostMapping @PutMapping @DeleteMapping代替
• 问题3：每个方法响应json都需要加上@ResponseBody注解，重复性太高。
  1.将ResponseBody提到类上面，让所有的方法都有@ResponseBody的功能 2.使用@RestController注解替换@Controller与@ResponseBody注解，简化书写

@RestController //@Controller + ReponseBody
@RequestMapping("/books")
public class BookController {
    
 //@RequestMapping(method = RequestMethod.POST)
    @PostMapping
    public String save(@RequestBody Book book){
        System.out.println("book save..." + book);
        return "{'module':'book save'}";
   }
 
    //@RequestMapping(value = "/{id}",method = RequestMethod.DELETE)
    @DeleteMapping("/{id}")
    public String delete(@PathVariable Integer id){
        System.out.println("book delete..." + id);
        return "{'module':'book delete'}";
   }
 
    //@RequestMapping(method = RequestMethod.PUT)
@PutMapping
    public String update(@RequestBody Book book){
        System.out.println("book update..." + book);
        return "{'module':'book update'}";
   }
 
    //@RequestMapping(value = "/{id}",method = RequestMethod.GET)
    @GetMapping("/{id}")
    public String getById(@PathVariable Integer id){
        System.out.println("book getById..." + id);
        return "{'module':'book getById'}";
   }
 
    //@RequestMapping(method = RequestMethod.GET)
    @GetMapping
    public String getAll(){
        System.out.println("book getAll...");
        return "{'module':'book getAll'}";
   }
    
}

SSM整合

整合配置

创建Maven的web项目

添加依赖

<?xml version="1.0" encoding="UTF-8"?>
 
<project xmlns="http://maven.apache.org/POM/4.0.0" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 
http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
 
  <groupId>com.itheima</groupId>
  <artifactId>springmvc_08_ssm</artifactId>
<version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>
 
  <dependencies>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>5.2.10.RELEASE</version>
    </dependency>
 
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>5.2.10.RELEASE</version>
    </dependency>
 
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-test</artifactId>
      <version>5.2.10.RELEASE</version>
    </dependency>
 
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.5.6</version>
    </dependency>
 
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>1.3.0</version>
    </dependency>
 
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.47</version>
    </dependency>
 
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>druid</artifactId>
      <version>1.1.16</version>
    </dependency>
 
    <dependency>
<groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
      <scope>test</scope>
    </dependency>
 
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>3.1.0</version>
      <scope>provided</scope>
    </dependency>
 
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.9.0</version>
    </dependency>
  </dependencies>
 
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.tomcat.maven</groupId>
        <artifactId>tomcat7-maven-plugin</artifactId>
        <version>2.1</version>
        <configuration>
          <port>80</port>
          <path>/</path>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

创建项目包结构

image.png

创建SpringConfig配置类

@Configuration
@ComponentScan({"com.itheima.service"})
@PropertySource("classpath:jdbc.properties")
@Import({JdbcConfig.class,MyBatisConfig.class})
@EnableTransactionManagement
public class SpringConfig {
}

创建JdbcConfig配置类

public class JdbcConfig {
    @Value("${jdbc.driver}")
    private String driver;
    @Value("${jdbc.url}")
    private String url;
    @Value("${jdbc.username}")
    private String username;
    @Value("${jdbc.password}")
    private String password;
 
    @Bean
    public DataSource dataSource(){
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(driver);
dataSource.setUrl(url);
        dataSource.setUsername(username);
        dataSource.setPassword(password);
        return dataSource;
   }
 
    @Bean
    public PlatformTransactionManager transactionManager(DataSource 
dataSource){
        DataSourceTransactionManager ds = new DataSourceTransactionManager();
        ds.setDataSource(dataSource);
        return ds;
   }
}

创建MybatisConfig配置类

public class MyBatisConfig {
    @Bean
    public SqlSessionFactoryBean sqlSessionFactory(DataSource dataSource){
        SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
        factoryBean.setDataSource(dataSource);
        factoryBean.setTypeAliasesPackage("com.itheima.domain");
        return factoryBean;
   }
 
    @Bean
    public MapperScannerConfigurer mapperScannerConfigurer(){
        MapperScannerConfigurer msc = new MapperScannerConfigurer();
        msc.setBasePackage("com.itheima.dao");
        return msc;
   }
}

创建jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/ssm_db
jdbc.username=root
jdbc.password=root

创建SpringMVC配置类

@Configuration
@ComponentScan("com.itheima.controller")
@EnableWebMvc
public class SpringMvcConfig {
}

创建Web项目入口配置类

public class ServletConfig extends 
AbstractAnnotationConfigDispatcherServletInitializer {
    //加载Spring配置类
    protected Class<?>[] getRootConfigClasses() {
        return new Class[]{SpringConfig.class};
   }
    //加载SpringMVC配置类
    protected Class<?>[] getServletConfigClasses() {
        return new Class[]{SpringMvcConfig.class};
   }
    //设置SpringMVC请求地址拦截规则
    protected String[] getServletMappings() {
        return new String[]{"/"};
   }
    //设置post请求中文乱码过滤器
    @Override
    protected Filter[] getServletFilters() {
        CharacterEncodingFilter filter = new CharacterEncodingFilter();
        filter.setEncoding("utf-8");
        return new Filter[]{filter};
   }
}

功能模块开发

创建数据库及表

create database ssm_db character set utf8;
use ssm_db;
create table tbl_book(
 id int primary key auto_increment,
 type varchar(20),
 name varchar(50),
 description varchar(255)
)
 
insert  into `tbl_book`(`id`,`type`,`name`,`description`) values (1,'计算机理
论','Spring实战 第五版','Spring入门经典教程，深入理解Spring原理技术内幕'),(2,'计算机理
论','Spring 5核心原理与30个类手写实践','十年沉淀之作，手写Spring精华思想'),(3,'计算机理
论','Spring 5设计模式','深入Spring源码刨析Spring源码中蕴含的10大设计模式'),(4,'计算机
理论','Spring MVC+Mybatis开发从入门到项目实战','全方位解析面向Web应用的轻量级框架，带你
成为Spring MVC开发高手'),(5,'计算机理论','轻量级Java Web企业应用实战','源码级刨析
Spring框架，适合已掌握Java基础的读者'),(6,'计算机理论','Java核心技术 卷Ⅰ 基础知识(原书
第11版)','Core Java第11版，Jolt大奖获奖作品，针对Java SE9、10、11全面更新'),(7,'计算
机理论','深入理解Java虚拟机','5个纬度全面刨析JVM,大厂面试知识点全覆盖'),(8,'计算机理
论','Java编程思想(第4版)','Java学习必读经典，殿堂级著作！赢得了全球程序员的广泛赞誉'),
(9,'计算机理论','零基础学Java(全彩版)','零基础自学编程的入门图书，由浅入深，详解Java语言
的编程思想和核心技术'),(10,'市场营销','直播就这么做:主播高效沟通实战指南','李子柒、李佳
奇、薇娅成长为网红的秘密都在书中'),(11,'市场营销','直播销讲实战一本通','和秋叶一起学系列网
络营销书籍'),(12,'市场营销','直播带货:淘宝、天猫直播从新手到高手','一本教你如何玩转直播的
书，10堂课轻松实现带货月入3W+');

编写模型类

public class Book {
    private Integer id;
    private String type;
    private String name;
    private String description;
    //getter...setter...toString省略
}

编写Dao接口

public interface BookDao {
 
//   @Insert("insert into tbl_book values(null,#{type},#{name},#
{description})")
    @Insert("insert into tbl_book (type,name,description) values(#{type},#
{name},#{description})")
    public void save(Book book);
 
    @Update("update tbl_book set type = #{type}, name = #{name}, description 
= #{description} where id = #{id}")
public void update(Book book);
 
    @Delete("delete from tbl_book where id = #{id}")
    public void delete(Integer id);
 
    @Select("select * from tbl_book where id = #{id}")
    public Book getById(Integer id);
 
    @Select("select * from tbl_book")
    public List<Book> getAll();
}

编写Service接口和实现类

@Transactional
public interface BookService {
    /**
     * 保存
     * @param book
     * @return
     */
    public boolean save(Book book);
 
    /**
     * 修改
     * @param book
     * @return
     */
    public boolean update(Book book);
 
    /**
     * 按id删除
     * @param id
     * @return
     */
    public boolean delete(Integer id);
 
    /**
     * 按id查询
     * @param id
     * @return
     */
    public Book getById(Integer id);
 
    /**
     * 查询全部
     * @return
 */
    public List<Book> getAll();
}

@Service
public class BookServiceImpl implements BookService {
    @Autowired
    private BookDao bookDao;
 
    public boolean save(Book book) {
        bookDao.save(book);
        return true;
   }
 
    public boolean update(Book book) {
        bookDao.update(book);
        return true;
   }
 
    public boolean delete(Integer id) {
        bookDao.delete(id);
        return true;
   }
 
    public Book getById(Integer id) {
        return bookDao.getById(id);
   }
 
    public List<Book> getAll() {
        return bookDao.getAll();
   }
}

编写Contorller类

@RestController
@RequestMapping("/books")
public class BookController {
 
    @Autowired
    private BookService bookService;
 
    @PostMapping
    public boolean save(@RequestBody Book book) {
        return bookService.save(book);
   }
 
    @PutMapping
    public boolean update(@RequestBody Book book) {
        return bookService.update(book);
   }
 
    @DeleteMapping("/{id}")
    public boolean delete(@PathVariable Integer id) {
        return bookService.delete(id);
   }
 
    @GetMapping("/{id}")
    public Book getById(@PathVariable Integer id) {
        return bookService.getById(id);
   }
 
    @GetMapping
public List<Book> getAll() {
        return bookService.getAll();
   }
}

单元测试

新建测试类

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = SpringConfig.class)
public class BookServiceTest {
 
}

注入Service类

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = SpringConfig.class)
public class BookServiceTest {
 
    @Autowired
    private BookService bookService;
 
 
}

编写测试方法

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = SpringConfig.class)
public class BookServiceTest {
 
    @Autowired
    private BookService bookService;
 
    @Test
    public void testGetById(){
        Book book = bookService.getById(1);
        System.out.println(book);
   }
@Test
    public void testGetAll(){
        List<Book> all = bookService.getAll();
        System.out.println(all);
   }
 
}

PostMan测试

• 新增

{
 "type":"类别测试数据",
    "name":"书名测试数据",
    "description":"描述测试数据"
}

• 修改
• 删除
• 查询单个
• 查询所有

统一结果封装

• 表现层与前端数据传输协议定义
• 我们就想能不能将返回结果的数据进行统一，具体如何来做，大体的思路为:
  1.为了封装返回的结果数据:创建结果模型类，封装数据到data属性中
  2.为了封装返回的数据是何种操作及是否操作成功:封装操作结果到code属性中
  3.操作失败后为了封装返回的错误信息:封装特殊消息到message(msg)属性中

public class Result{
 private Object data;
 private Integer code;
 private String msg;
}

表现层与前端数据传输协议实现

创建Result类

public class Result {
    //描述统一格式中的数据
    private Object data;
    //描述统一格式中的编码，用于区分操作，可以简化配置0或1表示成功失败
    private Integer code;
    //描述统一格式中的消息，可选属性
    private String msg;
public Result() {
   }
 //构造方法是方便对象的创建
    public Result(Integer code,Object data) {
        this.data = data;
        this.code = code;
   }
 //构造方法是方便对象的创建
    public Result(Integer code, Object data, String msg) {
        this.data = data;
        this.code = code;
        this.msg = msg;
   }
 //setter...getter...省略
}

定义返回码Code类

//状态码
public class Code {
    public static final Integer SAVE_OK = 20011;
    public static final Integer DELETE_OK = 20021;
    public static final Integer UPDATE_OK = 20031;
    public static final Integer GET_OK = 20041;
 
    public static final Integer SAVE_ERR = 20010;
    public static final Integer DELETE_ERR = 20020;
    public static final Integer UPDATE_ERR = 20030;
    public static final Integer GET_ERR = 20040;
}

修改Controller类的返回值

//统一每一个控制器方法返回值
@RestController
@RequestMapping("/books")
public class BookController {
 
    @Autowired
    private BookService bookService;
 
    @PostMapping
    public Result save(@RequestBody Book book) {
boolean flag = bookService.save(book);
        return new Result(flag ? Code.SAVE_OK:Code.SAVE_ERR,flag);
   }
 
    @PutMapping
    public Result update(@RequestBody Book book) {
        boolean flag = bookService.update(book);
        return new Result(flag ? Code.UPDATE_OK:Code.UPDATE_ERR,flag);
   }
 
    @DeleteMapping("/{id}")
    public Result delete(@PathVariable Integer id) {
        boolean flag = bookService.delete(id);
        return new Result(flag ? Code.DELETE_OK:Code.DELETE_ERR,flag);
   }
 
    @GetMapping("/{id}")
    public Result getById(@PathVariable Integer id) {
        Book book = bookService.getById(id);
        Integer code = book != null ? Code.GET_OK : Code.GET_ERR;
        String msg = book != null ? "" : "数据查询失败，请重试！";
        return new Result(code,book,msg);
   }
 
    @GetMapping
    public Result getAll() {
        List<Book> bookList = bookService.getAll();
        Integer code = bookList != null ? Code.GET_OK : Code.GET_ERR;
        String msg = bookList != null ? "" : "数据查询失败，请重试！";
        return new Result(code,bookList,msg);
   }
}

统一异常处理

@GetMapping("/{id}")
public Result getById(@PathVariable Integer id) {
    //手动添加一个错误信息
    if(id==1){
        int i = 1/0;
   }
    Book book = bookService.getById(id);
    Integer code = book != null ? Code.GET_OK : Code.GET_ERR;
    String msg = book != null ? "" : "数据查询失败，请重试！";
    return new Result(code,book,msg);
}

异常处理器的使用

创建异常处理器类

//@RestControllerAdvice用于标识当前类为REST风格对应的异常处理器
@RestControllerAdvice
public class ProjectExceptionAdvice {
    //除了自定义的异常处理器，保留对Exception类型的异常处理，用于处理非预期的异常
    @ExceptionHandler(Exception.class)
    public void doException(Exception ex){
     System.out.println("嘿嘿,异常你哪里跑！")
   }
}
 

异常解决方案的具体实现

自定义异常类

//自定义异常处理器，用于封装异常信息，对异常进行分类
public class SystemException extends RuntimeException{
    private Integer code;
 
    public Integer getCode() {
        return code;
   }
 
    public void setCode(Integer code) {
        this.code = code;
   }
 
    public SystemException(Integer code, String message) {
        super(message);
        this.code = code;
   }
 
    public SystemException(Integer code, String message, Throwable cause) {
        super(message, cause);
        this.code = code;
   }
 
}
 
//自定义异常处理器，用于封装异常信息，对异常进行分类
public class BusinessException extends RuntimeException{
    private Integer code;
 
    public Integer getCode() {
        return code;
   }
 
    public void setCode(Integer code) {
        this.code = code;
   }
 
    public BusinessException(Integer code, String message) {
        super(message);
this.code = code;
   }
 
    public BusinessException(Integer code, String message, Throwable cause) {
        super(message, cause);
        this.code = code;
   }
 
}

将其他异常包成自定义异常

public Book getById(Integer id) {
    //模拟业务异常，包装成自定义异常
    if(id == 1){
        throw new BusinessException(Code.BUSINESS_ERR,"请不要使用你的技术挑战我的
耐性!");
   }
    //模拟系统异常，将可能出现的异常进行包装，转换成自定义异常
    try{
        int i = 1/0;
   }catch (Exception e){
        throw new SystemException(Code.SYSTEM_TIMEOUT_ERR,"服务器访问超时，请重
试!",e);
   }
    return bookDao.getById(id);
}

• 方式一: try{}catch(){}在catch中重新throw我们自定义异常即可。
• 方式二:直接throw自定义异常即可

//状态码
public class Code {
    public static final Integer SAVE_OK = 20011;
    public static final Integer DELETE_OK = 20021;
 public static final Integer UPDATE_OK = 20031;
    public static final Integer GET_OK = 20041;
 
    public static final Integer SAVE_ERR = 20010;
    public static final Integer DELETE_ERR = 20020;
    public static final Integer UPDATE_ERR = 20030;
    public static final Integer GET_ERR = 20040;
    public static final Integer SYSTEM_ERR = 50001;
    public static final Integer SYSTEM_TIMEOUT_ERR = 50002;
    public static final Integer SYSTEM_UNKNOW_ERR = 59999;
 
    public static final Integer BUSINESS_ERR = 60002;
}

处理器类中处理自定义异常

//@RestControllerAdvice用于标识当前类为REST风格对应的异常处理器
@RestControllerAdvice
public class ProjectExceptionAdvice {
    //@ExceptionHandler用于设置当前处理器类对应的异常类型
    @ExceptionHandler(SystemException.class)
    public Result doSystemException(SystemException ex){
        //记录日志
        //发送消息给运维
        //发送邮件给开发人员,ex对象发送给开发人员
        return new Result(ex.getCode(),null,ex.getMessage());
   }
 
    @ExceptionHandler(BusinessException.class)
    public Result doBusinessException(BusinessException ex){
        return new Result(ex.getCode(),null,ex.getMessage());
   }
 
    //除了自定义的异常处理器，保留对Exception类型的异常处理，用于处理非预期的异常
    @ExceptionHandler(Exception.class)
    public Result doOtherException(Exception ex){
        //记录日志
        //发送消息给运维
        //发送邮件给开发人员,ex对象发送给开发人员
        return new Result(Code.SYSTEM_UNKNOW_ERR,null,"系统繁忙，请稍后再试！");
   }
}

前后台协议联调

• 因为添加了静态资源，SpringMVC会拦截，所有需要在SpringConfig的配置类中将静态资源进行放行。

@Configuration
public class SpringMvcSupport extends WebMvcConfigurationSupport {
    @Override
    protected void addResourceHandlers(ResourceHandlerRegistry registry) {
       
 registry.addResourceHandler("/pages/**").addResourceLocations("/pages/");
       
 registry.addResourceHandler("/css/**").addResourceLocations("/css/");
       
 registry.addResourceHandler("/js/**").addResourceLocations("/js/");
       
 registry.addResourceHandler("/plugins/**").addResourceLocations("/plugins
/");
   }
}

• 在SpringMvcConfig中扫描SpringMvcSupport

@Configuration
@ComponentScan({"com.itheima.controller","com.itheima.config"})
@EnableWebMvc
public class SpringMvcConfig {
}

拦截器

• 拦截器（Interceptor）是一种动态拦截方法调用的机制，在SpringMVC中动态拦截控制器方法的执行

拦截器开发

创建拦截器类

@Component
//定义拦截器类，实现HandlerInterceptor接口
//注意当前类必须受Spring容器控制
public class ProjectInterceptor implements HandlerInterceptor {
    @Override
    //原始方法调用前执行的内容
    public boolean preHandle(HttpServletRequest request, HttpServletResponse 
response, Object handler) throws Exception {
        System.out.println("preHandle...");
        return true;
   }
 
    @Override
    //原始方法调用后执行的内容
    public void postHandle(HttpServletRequest request, HttpServletResponse 
response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle...");
   }
 
    @Override
    //原始方法调用完成后执行的内容
    public void afterCompletion(HttpServletRequest request, 
HttpServletResponse response, Object handler, Exception ex) throws Exception 
{
        System.out.println("afterCompletion...");
   }
}

配置拦截器类

@Configuration
public class SpringMvcSupport extends WebMvcConfigurationSupport {
    @Autowired
    private ProjectInterceptor projectInterceptor;
 
    @Override
    protected void addResourceHandlers(ResourceHandlerRegistry registry) {
       
 registry.addResourceHandler("/pages/**").addResourceLocations("/pages/");
   }
 
    @Override
    protected void addInterceptors(InterceptorRegistry registry) {
        //配置拦截器
        registry.addInterceptor(projectInterceptor).addPathPatterns("/books" 
);
   }
}

SpringMVC添加SpringMvcSupport包扫描

@Configuration
@ComponentScan({"com.itheima.controller","com.itheima.config"})
@EnableWebMvc
public class SpringMvcConfig{
   
}

修改拦截器拦截规则

@Configuration
public class SpringMvcSupport extends WebMvcConfigurationSupport {
    @Autowired
    private ProjectInterceptor projectInterceptor;
 
    @Override
    protected void addResourceHandlers(ResourceHandlerRegistry registry) {
       
 registry.addResourceHandler("/pages/**").addResourceLocations("/pages/");
   }
 
    @Override
    protected void addInterceptors(InterceptorRegistry registry) {
        //配置拦截器
       
 registry.addInterceptor(projectInterceptor).addPathPatterns("/books","/books
/*" );
   }
}

简化SpringMvcSupport的编写

@Configuration
@ComponentScan({"com.itheima.controller"})
@EnableWebMvc
//实现WebMvcConfigurer接口可以简化开发，但具有一定的侵入性
public class SpringMvcConfig implements WebMvcConfigurer {
    @Autowired
    private ProjectInterceptor projectInterceptor;
 
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //配置多拦截器
       
 registry.addInterceptor(projectInterceptor).addPathPatterns("/books","/books
/*");
   }
}

拦截器参数

前置处理方法

public boolean preHandle(HttpServletRequest request,
                         HttpServletResponse response,
                         Object handler) throws Exception {
    System.out.println("preHandle");
    return true;
}

• 使用request对象可以获取请求数据中的内容，如获取请求头的Content-Type

public boolean preHandle(HttpServletRequest request, HttpServletResponse 
response, Object handler) throws Exception {
    String contentType = request.getHeader("Content-Type");
    System.out.println("preHandle..."+contentType);
    return true;
}

• 使用handler参数，可以获取方法的相关信息

public boolean preHandle(HttpServletRequest request, HttpServletResponse 
response, Object handler) throws Exception {
    HandlerMethod hm = (HandlerMethod)handler;
    String methodName = hm.getMethod().getName();//可以获取方法的名称
    System.out.println("preHandle..."+methodName);
    return true;
}

• 后置处理方法

public void postHandle(HttpServletRequest request,
                       HttpServletResponse response,
                       Object handler,
                       ModelAndView modelAndView) throws Exception {
    System.out.println("postHandle");
}

• 完成处理方法

public void afterCompletion(HttpServletRequest request,
                            HttpServletResponse response,
                            Object handler,
                            Exception ex) throws Exception {
    System.out.println("afterCompletion");
}

拦截器链配置

• 创建拦截器类

@Component
public class ProjectInterceptor2 implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse 
response, Object handler) throws Exception {
        System.out.println("preHandle...222");
        return false;
   }
 
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse 
response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle...222");
   }
 
    @Override
    public void afterCompletion(HttpServletRequest request, 
HttpServletResponse response, Object handler, Exception ex) throws Exception 
{
        System.out.println("afterCompletion...222");
   }
}

• 配置拦截器类

@Configuration
@ComponentScan({"com.itheima.controller"})
@EnableWebMvc
//实现WebMvcConfigurer接口可以简化开发，但具有一定的侵入性
public class SpringMvcConfig implements WebMvcConfigurer {
    @Autowired
    private ProjectInterceptor projectInterceptor;
    @Autowired
    private ProjectInterceptor2 projectInterceptor2;
 
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //配置多拦截器
       
 registry.addInterceptor(projectInterceptor).addPathPatterns("/books","/books
/*");
       
 registry.addInterceptor(projectInterceptor2).addPathPatterns("/books","/book
s/*");
 }
}

preHandle：与配置顺序相同，必定运行
postHandle:与配置顺序相反，可能不运行
afterCompletion:与配置顺序相反，可能不运行。
这个顺序不太好记，最终只需要把握住一个原则即可:以最终的运行结果为准