Java With Spring (二)

增删改查

作为一个简单的脚手架程序，我们先从最基本的功能开始，增删改查，返回json,包装JSON数据

配置好依赖，可以看到我们仅有最简单的三个依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.1.1</version>
</dependency>

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid-spring-boot-starter</artifactId>
    <version>1.1.10</version>
</dependency>

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>

从基本的目录结构

main
├── java
│   └── com
│       └── autodesk
│           └── www
│               ├── PlayWithBootApplication.java
│               ├── controller
│               │   └── PostController.java
│               ├── dao
│               │   └── PostDao.java
│               ├── exception
│               │   └── CustomExceptionHandler.java
│               ├── model
│               │   └── Post.java
│               ├── services
│               │   ├── PostService.java
│               │   └── impl
│               │       └── PostServiceImpl.java
│               └── utils
│                   └── JsonWrapResult.java
└── resources
    ├── application.properties
    ├── customize.properties
    └── mybatis
        ├── mapper
        │   └── PostMapper.xml
        └── mybatis-config.xml

基本的目录结构大体如此，测试目录就不列出来了，mybatic配置如下：

# database
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/springboot?useUnicode=true&characterEncoding=utf8&useSSL=false&serverTimezone=GMT%2B8
spring.datasource.username=root
spring.datasource.password=test
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
# MyBatis
mybatis.type-aliases-package=com.autodesk.www.model
mybatis.config-locations=classpath:mybatis/mybatis-config.xml
mybatis.mapper-locations=classpath:mybatis/mapper/*.xml
mybatis.configuration.log-impl= org.apache.ibatis.logging.stdout.StdOutImpl

PostController.java代码如下

@RestController
@RequestMapping("/post")
public class PostController {
    private PostService postService;
    @Autowired
    public PostController(PostService postService){
        this.postService = postService;
    }
    @PostMapping(path= "/add", consumes = "application/json", produces = "application/json")
    public JsonWrapResult addEmployee(@RequestBody Post post) throws Exception {
        this.postService.createPost(post);
        return JsonWrapResult.ok(this.postService.findAllPosts());
    }
    @RequestMapping(value = "/delete/{postId}", method = RequestMethod.DELETE)
    public JsonWrapResult deletePost(@PathVariable("postId") Long postId) {
        this.postService.deletePost(postId);
        return JsonWrapResult.ok("Delete Successful.");
    }
    @PostMapping(path= "/update", consumes = "application/json", produces = "application/json")
    public JsonWrapResult updateEmployee(@RequestBody Post post) throws Exception {
        this.postService.updatePost(post);
        return JsonWrapResult.ok(this.postService.findAllPosts());
    }
    @RequestMapping("/query/{id}")
    public JsonWrapResult testQuery(@PathVariable Long id) {
        return JsonWrapResult.ok(postService.findPost(id));
    }
    @RequestMapping(value = "/all", method = RequestMethod.GET)
    public JsonWrapResult listAllPosts() {  
    List<Post> allPosts = this.postService.findAllPosts();
    return JsonWrapResult.ok(allPosts);
    }

PostDao.java代码如下

@Repository
@Mapper
public interface PostDao {
    void save(Post post);
    void delete(Long postId);
    void update(Post post);
    Post find(Long postId);
    List<Post> findAll();
}

PostService.java代码如下

public interface PostService {
    void createPost(Post post);
    void deletePost(Long postId);
    void updatePost(Post post);
    Map<String, Object> findPost(Long postId);
    List<Post> findAllPosts();
}

Post.java代码如下

public class Post implements Serializable {
    private static final long serialVersionUID = 1L;
    private Long id;
    private String title;
    private String content;
    private Timestamp creationDate;
    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    public String getTitle() {
        return title;
    }
    public void setTitle(String title) {
        this.title = title;
    }
    public String getContent() {
        return content;
    }
    public void setContent(String content) {
        this.content = content;
    }
    public Timestamp getCreationDate() {
        return creationDate;
    }
    public void setCreationDate(Timestamp creationDate) {
        this.creationDate = creationDate;
    }
    @Override
    public String toString() {
        return "Post [id=" + id + ", title=" + title + ", content=" + content + ", creationDate=" + creationDate + "]";
    }
}

PostServiceImpl.java代码如下

@Service("postService")
@Transactional
public class PostServiceImpl implements PostService {
    private PostDao postDao;
    @Autowired
    public PostServiceImpl(PostDao postDao){
        this.postDao = postDao;
    }
    @Override
    public void createPost(Post post) {
        post.setCreationDate(new Timestamp(System.currentTimeMillis()));
        this.postDao.save(post);
    }
    @Override
    public void deletePost(Long postId) {
        this.postDao.delete(postId);
    }
    @Override
    public void updatePost(Post post) {
        this.postDao.update(post);
    }
    @Override
    public Map<String, Object> findPost(Long postId) {
        Map<String, Object> attributes = new HashMap<>();
        Post post = this.postDao.find(postId);
        attributes.put("post", post);
        return attributes;
    }
    @Override
    public List<Post> findAllPosts() {
        return this.postDao.findAll();
    }
}

postMapper.xml配置的mybatic如下：

<mapper namespace="com.autodesk.www.dao.PostDao">
    <resultMap id="PostResultMap" type="com.autodesk.www.model.Post">
        <id property="id" column="post_id"/>
        <result property="title" column="post_title"/>
        <result property="content" column="post_content"/>
        <result property="creationDate" column="post_creation_date"/>
    </resultMap>
    <insert id="save">
        INSERT INTO `T_POST` (title, content, creationDate) VALUES (#{title}, #{content}, #{creationDate})
    </insert>
    <select id="findAll" resultMap="PostResultMap">
        SELECT
            p.id as post_id,
            p.title as post_title,
            p.content as post_content,
            p.creationDate as post_creation_date
        FROM T_POST p
        ORDER BY p.creationDate DESC
    </select>
    <select id="find" resultMap="PostResultMap">
        SELECT
            p.id as post_id,
            p.title as post_title,
            p.content as post_content,
            p.creationDate as post_creation_date
        FROM T_POST p
        WHERE p.id = #{postId}
    </select>
    <update id="update">
        UPDATE T_POST SET 
            title = #{title},
            content = #{content}
        WHERE id = #{id}
    </update>
    <delete id="delete" parameterType="Long">
        DELETE FROM T_POST WHERE id = #{postId}
    </delete>
</mapper>

mybatic基本配置如下mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <typeAliases>
        <typeAlias alias="Integer" type="java.lang.Integer" />
        <typeAlias alias="Long" type="java.lang.Long" />
        <typeAlias alias="String" type="java.lang.String" />
        <typeAlias alias="HashMap" type="java.util.HashMap" />
        <typeAlias alias="Date" type="java.util.Date" />
        <typeAlias alias="LinkedHashMap" type="java.util.LinkedHashMap" />
        <typeAlias alias="ArrayList" type="java.util.ArrayList" />
        <typeAlias alias="LinkedList" type="java.util.LinkedList" />
    </typeAliases>
</configuration>

完成基本的curd

这样我们就有了基本的CURD,接着会在接下来的文章中，一步步的添加成具有完备功能的脚手架
Happy hacking…

不积小流，无以成江海