mybatis 在前端對資料庫進行增刪改查
阿新 • • 發佈：2018-12-18
Springboot 對資料庫進行增刪改查
首先要實現在idea裡面能實現對資料看的增刪改查，最後再實現前後端互動
1.首先在資料庫裡面先建好資料庫（test01）和表（t_user）
2.配置檔案pom.xml
<?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.wencui</groupId> <artifactId>demo</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>demo</name> <description>Demo project for Spring Boot</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.0.5.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.xmlunit</groupId> <artifactId>xmlunit-core</artifactId> </dependency> <dependency> <groupId>com.vaadin.external.google</groupId> <artifactId>android-json</artifactId> <version>RELEASE</version> </dependency> <dependency> <groupId>net.minidev</groupId> <artifactId>json-smart</artifactId> <version>RELEASE</version> </dependency> <dependency> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-clean-plugin</artifactId> <version>2.5</version> </dependency> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>1.3.1</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <version>4.3.13.RELEASE</version> <scope>test</scope> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-thymeleaf</artifactId> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
3.在model檔案下建立實體類User
public class User { //和表裡面的屬性一一對應 private int id; private String username; private String password; private String nickname; private int gid; //構造方法 //快捷鍵：Ctrl + Insert public User(int id, String username, String password, String nickname, int gid) { this.id = id; this.username = username; this.password = password; this.nickname = nickname; this.gid = gid; } //getter 和 setter 方法 //快捷鍵 ： Ctrl + Insert public User() { } public int getId() { return id; } public void setId(int id) { this.id = id; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getNickname() { return nickname; } public void setNickname(String nickname) { this.nickname = nickname; } public int getGid() { return gid; } public void setGid(int gid) { this.gid = gid; } //用於列印顯示 @Override public String toString() { return "User{" + "id=" + id + ", username='" + username + '\'' + ", password='" + password + '\'' + ", nickname='" + nickname + '\'' + ", gid=" + gid + '}'; } }
4.新建配置檔案mapper 下的UserMapper.xml 檔案
注意：此檔案是對資料庫進行操作，這裡面的增刪改查語句是在資料庫裡面都可以執行 的
<?xml version="1.0" encoding="utf-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http:/5/mybatis.org/dtd/mybatis-3-mapper.dtd"> <!--對應 dao下的 Usermapper介面 --> <mapper namespace="com.wencui.demo.dao.UserMapper"> <!--配置資料庫的連結資訊，注意，column 是資料庫的欄位的屬性，property 是實體類 User 裡面的屬性--> <resultMap id="baseResultMap" type="com.wencui.demo.model.User"> <id column="id" property="id" jdbcType="INTEGER"/> <result column="nick_name" property="nickname" jdbcType="INTEGER"/> <result column="user_name" property="username" jdbcType="INTEGER"/> <result column="pass_word" property="password" jdbcType="VARCHAR"/> <result column="gid" property="gid" jdbcType="VARCHAR"/> </resultMap> <!--要返回的資料庫裡面的內容--> <sql id="baseColumnList"> id, nick_name, user_name,pass_word,gid </sql> <!--增 這裡的 id 要對應 Usermapper 裡面的方法名 --> <insert id="add" parameterType="com.wencui.demo.model.User"> insert into t_user <trim prefix="(" suffix=")" suffixOverrides=","> <!--在資料庫中 id 設定的是主鍵，並且自動遞增，所以不需要手動新增 id--> <!-- <if test="id != null"> id, </if>--> <if test="username != null"> user_name, </if> <if test="nickname != null"> nick_name, </if> <if test="password != null"> pass_word, </if> <if test="gid != null"> gid, </if> </trim> <trim prefix="values (" suffix=")" suffixOverrides=","> <!--<if test="id != null"> #{id,jdbcType=INTEGER}, </if>--> <if test="username != null"> #{username,jdbcType=VARCHAR}, </if> <if test="nickname != null"> #{nickname,jdbcType=VARCHAR}, </if> <if test="password != null"> #{password,jdbcType=VARCHAR}, </if> <if test="gid != null"> #{gid,jdbcType=VARCHAR}, </if> </trim> </insert> <!--刪，通過 id 刪，parameterType 表示 dao檔案下 Usermapper接口裡面 delete方法傳的引數的資料型別--> <delete id="delete" parameterType="java.lang.Integer" > delete from t_user where id = #{id,jdbcType=INTEGER} </delete> <!--改 ，通過 id 改，parameterType 表示 dao檔案下 Usermapper接口裡面 update方法傳的引數的資料型別--> <update id="update" parameterType="com.wencui.demo.model.User" > update t_user set user_name = #{username,jdbcType=VARCHAR}, pass_word = #{password,jdbcType=VARCHAR}, nick_name = #{nickname,jdbcType=VARCHAR}, gid = #{gid,jdbcType=INTEGER} where id = #{id,jdbcType=INTEGER} </update> <!--查，通過查 id，rusultMap 對應的是上面的resultMap 裡面的id，parameterType 表示 dao檔案下 Usermapper接口裡面 loadid方法傳的引數的資料型別 --> <select id="loadid" resultMap="baseResultMap" parameterType="java.lang.Integer"> SELECT <!--這裡的是上面的sql 裡面的id--> <include refid="baseColumnList"/> FROM t_user WHERE id = #{id} </select> <!--查，通過 username 查，rusultMap 對應的是上面的resultMap 裡面的id，parameterType 表示 dao檔案下 Usermapper接口裡面 loadname方法傳的引數的資料型別--> <select id="loadname" resultMap="baseResultMap" parameterType="java.lang.String"> SELECT <!--這裡的是上面的sql 裡面的id--> <include refid="baseColumnList"/> FROM t_user WHERE user_name = #{username} </select> <!--返回Json資料,rusultMap 對應的是上面的resultMap 裡面的id，parameterType 表示 dao檔案下 Usermapper接口裡面 list方法傳的引數的資料型別--> <select id="list" resultMap="baseResultMap" parameterType="java.util.HashMap"> select <!--這裡的是上面的sql 裡面的id--> <include refid="baseColumnList"/> from t_user </select> </mapper>
5.在dao（持久層）裡面寫增刪改查的方法
注意：Usermapper這是一個介面，定義方法名字是要和mapper檔案下的Usermapper.xml的id值相對應
//@mapper 是為了找到 mybitis 的配置檔案 mapper，不寫會報錯
@Mapper
public interface UserMapper {
//增
public void add(User user);
//刪
public void delete(int id);
//改
public void update(User user);
//通過id查，用於輔助刪除，改
public User loadid(int id);
//通過username來查，用於輔助改
public User loadname(User username);
//返回 JSon 資料
public List<User> list();
}
6.這時我們可以寫一個測試類來測試一下dao裡面的Usermapper接口裡面的方法能不能用
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = DemoApplication.class)
public class TestUserDao {
@Autowired
protected UserMapper userMapper;
@org.junit.Test
public void Testadd() {
User user = new User();
user.setUsername("溫dada");
user.setPassword("123");
user.setNickname("wen");
user.setGid(2);
userMapper.add(user);
}
@org.junit.Test
public void Testdelete(){
userMapper.delete(13);
}
@org.junit.Test
public void Testupdate(){
User user = new User();
user.setId(7);
user.setUsername("溫大大");
user.setPassword("123");
user.setNickname("wen");
user.setGid(2);
userMapper.update(user);
}
@org.junit.Test
public void Testloadid(){
User user = new User();
int id = user.getId();
userMapper.loadid(id);
System.out.println(id);
System.out.println(userMapper.loadid(id));
}
@org.junit.Test
public void Testlist(){
System.out.println(userMapper.list());
}
}
7.新建service（業務層）
這一層是用來和前端做資料操作用的，同樣要寫一個介面UserService用來寫方法，這裡介面就不用寫@Mapper了
public interface UserService {
//這裡面的方法和dao層裡面的UserMapper接口裡面的方法幾乎一樣就不做多的解釋
public List<User> list();
public void add(User user);
public User loadid(int id);
public void delete(int id);
public void update(User user);
// 這裡新增一個方法，用於登入用
public String login(String url,User user);
}
8. 再在service下寫一個實現類UserServiceImpl
//@Service 標註這是一個service，不可不寫
@Service("userService")
public class UserServiceImpl implements UserService {
//@Resouce 表示通過名字注入
@Resource
private UserMapper userMapper;
//@Override是Java5的元資料，自動加上去的一個標誌，告訴你說下面這個方法是從父類/介面 繼承過來的，不寫會報錯
@Override
public List<User> list() {
return userMapper.list();
}
@Override
public void add(User user) {
userMapper.add(user);
}
@Override
public User loadid(int id) {
return userMapper.loadid(id);
}
@Override
public void delete(int id) {
userMapper.delete(id);
}
@Override
public void update(User user) {
userMapper.update(user);
}
@Override
public String login(String url,User user) {
User name =userMapper.loadname(user);
if (name == null){
System.out.println("此使用者不存在！請註冊。");
url="/login/login";
}
else {
if(name.getPassword().equals( user.getPassword())){
url ="/user/load";
}
else {
System.out.println("密碼錯誤");
}
}
return url;
}
}
}
9.新建一個controller 資料夾
在Controller裡面新建類UserController去檢驗service層
//@Controller表示這是一個Controller
@Controller
@RequestMapping("/user") //表示網頁訪問的路徑
public class UserController {
//@Autowired 表示通過型別來找，區分 @Rsource
@Autowired
private UserService userService;
@RequestMapping("/listjson")
@ResponseBody // 表示在網頁中返回Json資料
public List<User> list() {
System.out.println(userService.list());
return userService.list();
}
// get方法，從後臺得到資料
@RequestMapping(value = "/load",method = RequestMethod.GET)
public String load(Model model){
model.addAttribute("users",new User());
model.addAttribute("users",userService.list());
return "user/load"; // 返回到load的頁面
}
@RequestMapping(value = "/add",method = RequestMethod.GET)
public String add(Model model){
model.addAttribute("user",new User());
return "user/add";
}
// post方法，向後臺傳送資料
@RequestMapping(value = "/add",method = RequestMethod.POST)
public String add(User user){
userService.add(user);
// System.out.println(user);
return "redirect:/user/load"; //跳轉到load頁面
}
@RequestMapping(value = "/{id}/delete", method = RequestMethod.GET)
public String delete(@PathVariable int id) {
userService.delete(id);
// System.out.println(id);
return "redirect:/user/load";
}
@RequestMapping(value = "/{id}/update",method = RequestMethod.GET)
public String update(@PathVariable int id,Model model){
model.addAttribute(userService.loadid(id));
model.addAttribute("user",userService.loadid(id));
// System.out.println(userService.loadid(id));
return "user/update";
}
@RequestMapping(value = "/{id}/update",method = RequestMethod.POST)
public String update(User user ){
userService.update(user);
// System.out.println(user);
return "redirect:/user/load";
}
}
再新建一個LoginController 來寫登入，也可以直接寫在UserController裡面，不過要注意路徑是否改變
@Controller
@RequestMapping("/login")
public class LoginController {
@Autowired
private UserService userService;
@RequestMapping(value = "/login", method = RequestMethod.GET)
public String login(Model model){
model.addAttribute("user", new User());
return "user/login";
}
@RequestMapping(value = "/login", method = RequestMethod.POST)
public String login(User user){
String url = "/login";
url = userService.login(url,user);
System.out.println(user);
System.out.println(url);
return "redirect:"+url;
}
}
UserController裡面對應的HTML頁面
add
<!DOCTYPE html>
<html lang="zh-CN"
xmlns="http://www.w3.org/1999/xhtml"
xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="utf-8 ">
<title>study01 - helloWorld</title>
</head>
<body>
<div id="bigbox">
<form class="form-horizontal" method="post" th:action="@{add}" th:object="${user}">
<fieldset>
<div id="legend" class="">
<legend class="">新增使用者</legend>
</div>
<div class="control-group">
<label class="control-label" >使用者名稱</label>
<div class="controls">
<input type="text" placeholder="username" class="input-xlarge" th:field="*{username}"/>
<p class="help-block"></p>
</div>
</div><div class="control-group">
<!-- Text input-->
<label class="control-label" >密碼</label>
<div class="controls">
<input type="text" placeholder="password" class="input-xlarge" th:field="*{password}"/>
<p class="help-block"></p>
</div>
</div>
<div class="control-group">
<!-- Text input-->
<label class="control-label">暱稱</label>
<div class="controls">
<input type="text" placeholder="nickname" class="input-xlarge" th:field="*{nickname}"/>
<p class="help-block"></p>
</div>
</div>
<div class="control-group">
<!-- Text input-->
<label class="control-label">gid</label>
<div class="controls">
<input type="text" placeholder="gid" class="input-xlarge" th:field="*{gid}"/>
<p class="help-block"></p>
</div>
</div>
<div class="control-group">
<label class="control-label"></label>
<!-- Button -->
<div class="controls">
<button class="btn btn-success">提交</button>
</div>
</div>
</fieldset>
</form>
</div>
</body>
</html>
update
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<html lang="en">
<head>
<meta charset="UTF-8">
<title>updete</title>
</head>
<body>
<form class="form-horizontal" method="post" th:action="@{update}" th:object="${user}">
<fieldset>
<div id="legend" class="">
<legend class="">修改使用者</legend>
</div>
<div class="control-group">
<label class="control-label" >使用者名稱</label>
<div class="controls">
<input type="text" placeholder="username" class="input-xlarge" th:field="*{username}"/>
<p class="help-block"></p>
</div>
</div><div class="control-group">
<!-- Text input-->
<label class="control-label" >密碼</label>
<div class="controls">
<input type="text" placeholder="password" class="input-xlarge" th:field="*{password}"/>
<p class="help-block"></p>
</div>
</div>
<div class="control-group">
<!-- Text input-->
<label class="control-label">暱稱</label>
<div class="controls">
<input type="text" placeholder="nickname" class="input-xlarge" th:field="*{nickname}"/>
<p class="help-block"></p>
</div>
</div>
<div class="control-group">
<!-- Text input-->
<label class="control-label">gid</label>
<div class="controls">
<input type="text" placeholder="gid" class="input-xlarge" th:field="*{gid}"/>
<p class="help-block"></p>
</div>
</div>
<div class="control-group">
<label class="control-label"></label>
<!-- Button -->
<div class="controls">
<button class="btn btn-success">提交</button>
</div>
</div>
</fieldset>
</form>
</body>
</html>
load
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8"/>
<title>load</title>
</head>
<body>
<div>
<ul th:each="user:${users}">
<li th:text="${user.id}"></li>
<li th:text="${user.username}"></li>
<li th:text="${user.password}"></li>
<li th:text="${user.nickname}"></li>
<li th:text="${user.gid}"></li>
<li><a th:href="@{{id}/update(id=${user.id})}">修改</a></li>
<li><a th:href="@{{id}/delete(id=${user.id})}">刪除</a></li>
</ul>
</div>
</body>
</html>
login
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>login</title>
</head>
<body>
<div id="bigbox">
<form class="form-horizontal" method="post" th:action="@{login}" th:object="${user}">
<fieldset>
<div id="legend" class="">
<legend class="">登入</legend>
</div>
<div class="control-group">
<label class="control-label" >使用者名稱</label>
<div class="controls">
<input type="text" placeholder="username" class="input-xlarge" th:field="*{username}"/>
<p class="help-block"></p>
</div>
</div><div class="control-group">
<!-- Text input-->
<label class="control-label" >密碼</label>
<div class="controls">
<input type="text" placeholder="password" class="input-xlarge" th:field="*{password}"/>
<p class="help-block"></p>
</div>
</div>
<div class="control-group">
<label class="control-label"></label>
<!-- Button -->
<div class="controls">
<button class="btn btn-success" ><a >登入</a></button>
</div>
<div class="controls">
<button class="" ><a href="/user/add">註冊</a></button>
</div>
</div>
</fieldset>
</form>
</div>
</body>
</html>
10. 最後新建一個application.properties
spring.thymeleaf.cache=false
#連結資料庫
spring.datasource.url=jdbc:mysql://localhost:3306/test01?useUnicode=true&characterEncoding=utf-8
spring.datasource.username=root
spring.datasource.password=你的密碼
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
#指定bean所在包
mybatis.type-aliases-package=com.wencui.demo.model
#指定對映檔案
mybatis.mapperLocations=classpath:mapper/*.xml
#列印mybatis的sql語句
logging.level.org.springframework=WARN
logging.level.org.mybatis=info
logging.file=logs/spring-boot-logging.log
server.port=8080
注意：在導包是要注意包的路徑，路徑會錯了會出現一些錯