原創作品，可以轉載，但是請標注出處地址：https://www.cnblogs.com/V1haoge/p/9971036.html
SpringBoot整合Mybatis
步驟
第一步：添加必要的jar包
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.3.1</version>
</dependency>
第二步：添加必要的配置
application.properties
##配置數據源
spring.datasource.url = jdbc:h2:mem:dbtest
spring.datasource.username = sa
spring.datasource.password = sa
spring.datasource.driverClassName =org.h2.Driver
第三步：添加配置類
// 該配置類用於配置自動掃描器，用於掃描自定義的mapper接口,MyBatis會針對這些接口生成代理來調用對應的XMl中的SQL
@Configuration
@MapperScan("com.example.springbootdemo.mapper")
public class MyBatisConfig {
}
這個注解必須手動配置是因為mapper接口的位置完全就是用戶自定義的，自動配置的時候也不可能找到還不存在的位置。
第四步：定義實體類型
@Data
@NoArgsConstructor
@AllArgsConstructor
@ToString
@EqualsAndHashCode
@Builder
@ApiModel("書籍模型")
public class Book {
@ApiModelProperty(value = "書籍ID", notes = "書籍ID",example = "1")
private Integer bookId;
@ApiModelProperty(value = "書籍頁數", notes = "書籍頁數",example = "100")
private Integer pageNum;
@ApiModelProperty(value = "書籍名稱", notes = "書籍名稱",example = "Java編程思想")
private String bookName;
@ApiModelProperty(value = "書籍類型", notes = "書籍類型",hidden = false)
private BookType BookType;
@ApiModelProperty(value = "書籍簡介")
private String bookDesc;
@ApiModelProperty(value = "書籍價格")
private Double bookPrice;
@ApiModelProperty(value = "創建時間",hidden = true)
private LocalDateTime createTime;
@ApiModelProperty(value = "修改時間",hidden = true)
private LocalDateTime modifyTime;
}
還有一個枚舉類型
public enum BookType {
TECHNOLOGY,//技術
LITERARY,//文學
HISTORY//歷史
;
}
實體類中使用了swagger2和Lombok中的注解，需要添加對應的jar包
第五步：定義mapper接口
public interface BookRepository {
int addBook(Book book);
int updateBook(Book book);
int deleteBook(int id);
Book getBook(int id);
List<Book> getBooks(Book book);
}
第六步：定義mapper配置
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.springbootdemo.mapper.BookRepository">
<insert id="addBook" parameterType="Book">
INSERT INTO BOOK(
<if test="pageNum != null">
PAGE_NUM,
</if>
<if test="bookType != null">
BOOK_TYPE,
</if>
<if test="bookName != null">
BOOK_NAME,
</if>
<if test="bookDesc != null">
BOOK_DESC,
</if>
<if test="bookPrice != null">
BOOK_PRICE,
</if>
CREATE_TIME,
MODIFY_TIME)
VALUES (
<if test="pageNum != null">
#{pageNum},
</if>
<if test="bookType != null">
#{bookType},
</if>
<if test="bookName != null">
#{bookName},
</if>
<if test="bookDesc != null">
#{bookDesc},
</if>
<if test="bookPrice != null">
#{bookPrice},
</if>
sysdate,sysdate)
</insert>
<update id="updateBook" parameterType="Book">
UPDATE BOOK SET
<if test="pageNum != null">
PAGE_NUM = #{pageNum},
</if>
<if test="bookType != null">
BOOK_TYPE = #{bookType},
</if>
<if test="bookDesc != null">
BOOK_DESC = #{bookDesc},
</if>
<if test="bookPrice != null">
BOOK_PRICE = #{bookPrice},
</if>
<if test="bookName != null">
BOOK_NAME = #{bookName},
</if>
MODIFY_TIME=sysdate
WHERE 1=1
<if test="bookId != null">
and BOOK_ID = #{bookId}
</if>
</update>
<delete id="deleteBook" parameterType="int">
delete from BOOK where BOOK_id=#{bookId}
</delete>
<select id="getBook" parameterType="int" resultMap="bookResultMap">
select * from BOOK where BOOK_ID=#{bookId}
</select>
<select id="getBooks" resultMap="bookResultMap">
select * from BOOK WHERE 1=1
<if test="bookId != null">
and BOOK_ID = #{bookId}
</if>
<if test="pageNum != null">
and PAGE_NUM = #{pageNum}
</if>
<if test="bookType != null">
and BOOK_TYPE = #{bookType}
</if>
<if test="bookDesc != null">
and BOOK_DESC = #{bookDesc}
</if>
<if test="bookPrice != null">
and BOOK_PRICE = #{bookPrice}
</if>
<if test="bookName != null">
and BOOK_NAME = #{bookName}
</if>
</select>
<resultMap id="bookResultMap" type="Book">
<id column="BOOK_ID" property="bookId"/>
<result column="PAGE_NUM" property="pageNum"/>
<result column="BOOK_NAME" property="bookName"/>
<result column="BOOK_TYPE" property="bookType"/>
<result column="BOOK_DESC" property="bookDesc"/>
<result column="BOOK_PRICE" property="bookPrice"/>
<result column="CREATE_TIME" property="createTime"/>
<result column="MODIFY_TIME" property="modifyTime"/>
</resultMap>
</mapper>
在這個配置文件中我們使用了MyBatis的動態SQL和參數映射
第七步：再次添加必要的配置
application.properties
#配置Xml配置的位置
mybatis.mapper-locations=classpath*:/mapper/*.xml
#配置實體類型別名
mybatis.type-aliases-package=com.example.springbootdemo.entity
這里的兩個配置也和之前的掃描器注解一樣，都是自動配置時未知的，需要手動配置，當然可能會存在默認的位置，但是一旦我們自定義了，就必須手動添加配置
第八步：定義service和controller
@Service
@Log4j2
public class BookService {
@Autowired
private BookRepository bookRepository;
public ResponseEntity<Book> addBook(final Book book) {
int num = bookRepository.addBook(book);
return ResponseEntity.ok(book);
}
public ResponseEntity<Integer> updateBook(final Book book){
return ResponseEntity.ok(bookRepository.updateBook(book));
}
public ResponseEntity<Integer> deleteBook(final int bookId){
return ResponseEntity.ok(bookRepository.deleteBook(bookId));
}
public ResponseEntity<Book> getBook(final int bookId) {
Book book = bookRepository.getBook(bookId);
return ResponseEntity.ok(book);
}
public ResponseEntity<List<Book>> getBooks(final Book book){
return ResponseEntity.ok(bookRepository.getBooks(book));
}
}
@RestController
@RequestMapping("/book")
@Api(description = "書籍接口")
@Log4j2
public class BookApi {
@Autowired
private BookService bookService;
@RequestMapping(value = "/addBook", method = RequestMethod.PUT)
@ApiOperation(value = "添加書籍", notes = "添加一本新書籍", httpMethod = "PUT")
public ResponseEntity<Book> addBook(final Book book){
return bookService.addBook(book);
}
@RequestMapping(value = "/updateBook", method = RequestMethod.POST)
@ApiOperation(value = "更新書籍", notes = "根據條件更新書籍信息", httpMethod = "POST")
public ResponseEntity<Integer> updateBook(final Book book){
return bookService.updateBook(book);
}
@RequestMapping(value = "/deleteBook", method = RequestMethod.DELETE)
@ApiOperation(value = "獲取一本書籍", notes = "根據ID獲取書籍", httpMethod = "DELETE")
public ResponseEntity<Integer> deleteBook(final int bookId){
return bookService.deleteBook(bookId);
}
@RequestMapping(value = "/getBook", method = RequestMethod.GET)
@ApiOperation(value = "獲取一本書籍", notes = "根據ID獲取書籍", httpMethod = "GET")
public ResponseEntity<Book> getBook(final int bookId){
return bookService.getBook(bookId);
}
@RequestMapping(value = "/getBooks", method = RequestMethod.GET)
@ApiOperation(value = "獲取書籍", notes = "根據條件獲取書籍", httpMethod = "GET")
public ResponseEntity<List<Book>> getBooks(final Book book){
return bookService.getBooks(book);
}
}
這里使用了swagger2的注解
至此設置完畢。
第十步：瀏覽器訪問
http://localhost:8080/swagger-ui.html
通過swagger界面可以看到我們定義的接口。
高級功能
分頁（兩種，簡單分頁RowBounds和攔截器分頁，插件）
RowBounds分頁
使用RowBounds分頁適用於小數據量的分頁查詢
使用方式是在查詢的Mapper接口上添加RowBounds參數即可，service傳參時需要指定其兩個屬性，當前頁和每頁數
1-定義分頁模型
@Data
@Builder
@ToString
@EqualsAndHashCode
@NoArgsConstructor
@AllArgsConstructor
public class MyPage<T> {
private Integer pageId;//當前頁
private Integer pageNum;//總頁數
private Integer pageSize;//每頁數
private Integer totalNum;//總數目
private List<T> body;//分頁結果
private Integer srartIndex;//開始索引
private boolean isMore;//是否有下一頁
}
2-定義mapper
public interface BookRepository {
// 省略多余內容
int count(Book book);
List<Book> getBooks(Book book, RowBounds rowBounds);
}
BookRepository.xml
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.springbootdemo.mapper.BookRepository">
<!--省略多余內容-->
<select id="getBooks" resultMap="bookResultMap">
select * from BOOK WHERE 1=1
<if test="bookId != null">
and BOOK_ID = #{bookId}
</if>
<if test="pageNum != null">
and PAGE_NUM = #{pageNum}
</if>
<if test="bookType != null">
and BOOK_TYPE = #{bookType}
</if>
<if test="bookDesc != null">
and BOOK_DESC = #{bookDesc}
</if>
<if test="bookPrice != null">
and BOOK_PRICE = #{bookPrice}
</if>
<if test="bookName != null">
and BOOK_NAME = #{bookName}
</if>
</select>
<select id="count" resultType="int">
select count(1) from BOOK WHERE 1=1
<if test="bookId != null">
and BOOK_ID = #{bookId}
</if>
<if test="pageNum != null">
and PAGE_NUM = #{pageNum}
</if>
<if test="bookType != null">
and BOOK_TYPE = #{bookType}
</if>
<if test="bookDesc != null">
and BOOK_DESC = #{bookDesc}
</if>
<if test="bookPrice != null">
and BOOK_PRICE = #{bookPrice}
</if>
<if test="bookName != null">
and BOOK_NAME = #{bookName}
</if>
</select>
<resultMap id="bookResultMap" type="Book">
<id column="BOOK_ID" property="bookId"/>
<result column="PAGE_NUM" property="pageNum"/>
<result column="BOOK_NAME" property="bookName"/>
<result column="BOOK_TYPE" property="bookType"/>
<result column="BOOK_DESC" property="bookDesc"/>
<result column="BOOK_PRICE" property="bookPrice"/>
<result column="CREATE_TIME" property="createTime"/>
<result column="MODIFY_TIME" property="modifyTime"/>
</resultMap>
</mapper>
3-定義service
@Service
@Log4j2
public class BookService {
@Autowired
private BookRepository bookRepository;
// 省略多余內容
// 使用RowBounds實現分頁
public ResponseEntity<MyPage<Book>> getBooksByRowBounds(int pageId,int pageSize){
MyPage<Book> myPage = new MyPage<>();
myPage.setPageId(pageId);
myPage.setPageSize(pageSize);
List<Book> books = bookRepository.getBooks(Book.builder().build(), new RowBounds(pageId,pageSize));
int totalNum = bookRepository.count(Book.builder().build());
myPage.setBody(books);
myPage.setTotalNum(totalNum);
return ResponseEntity.ok(myPage);
}
}
4-定義controller
@RestController
@RequestMapping("/book")
@Api(description = "書籍接口")
@Log4j2
public class BookApi {
@Autowired
private BookService bookService;
// 省略多余內容
@RequestMapping(value = "/getBooksPageByRowBounds", method = RequestMethod.GET)
@ApiOperation(value = "分頁獲取書籍", notes = "通過RowBounds分頁獲取書籍", httpMethod = "GET")
public ResponseEntity<PageInfo<Book>> getBooksPageByRowBounds(final int pageId, final int pageNum){
return bookService.getBooksByRowBounds(pageId, pageNum);
}
}
攔截器分頁
當面對大數據量的分頁時，RowBounds就力不從心的，這時需要我們使用分頁攔截器實現分頁。
這里其實可以直接使用插件PageHelper，其就是以攔截器技術實現的分頁查詢插件。
具體使用方法見SpringBoot整合MyBatis分頁插件PageHelper
自定義類型轉換器（枚舉轉換器）
public class BookTypeEnumHandler extends BaseTypeHandler<BookType> {
/**
* 用於定義設置參數時，該如何把Java類型的參數轉換為對應的數據庫類型
*/
@Override
public void setNonNullParameter(PreparedStatement ps, int i, BookType parameter, JdbcType jdbcType) throws SQLException {
int j = 0;
for (BookType bookType : BookType.values()){
if(bookType.equals(parameter)){
ps.setString(i, j +"");
return;
}
j++;
}
}
/**
* 用於定義通過字段名稱獲取字段數據時，如何把數據庫類型轉換為對應的Java類型
*/
@Override
public BookType getNullableResult(ResultSet rs, String columnName) throws SQLException {
int j = Integer.valueOf(rs.getString(columnName));
if(j >= BookType.values().length) {
return null;
}
int i = 0;
for(BookType bookType:BookType.values()){
if(j == i){
return bookType;
}
i++;
}
return null;
}
/**
* 用於定義通過字段索引獲取字段數據時，如何把數據庫類型轉換為對應的Java類型
*/
@Override
public BookType getNullableResult(ResultSet rs, int columnIndex) throws SQLException {
return null;
}
/**
* 用定義調用存儲過程后，如何把數據庫類型轉換為對應的Java類型
*/
@Override
public BookType getNullableResult(CallableStatement cs, int columnIndex) throws SQLException {
return null;
}
}
使用@Mapper（不常用，可不看）
注意：使用@Mapper注解的時候是不需要添加xml配置Mapper文件的，SQL腳本在接口方法的注解內部定義
第一步：定義實體類
@Data
@Builder
@ToString
@EqualsAndHashCode
@NoArgsConstructor
@AllArgsConstructor
public class Tree {
private Integer treeId;
private String treeName;
private Integer treeAge;
private Double treeHight;
private TreeType treeType;
private TreeState treeState;
private String treeDesc;
}
第二步：定義持久層
@Mapper
public interface TreeRepository {
@Insert("INSERT INTO TREE (TREE_NAME,TREE_AGE,TREE_HIGHT,TREE_TYPE,TREE_STATE,TREE_DESC) VALUES (#{treeName},#{treeAge},#{treeHight},#{treeType},#{treeState},#{treeDesc}) ")
int addTree(Tree tree);
// 此處treeState是一個枚舉，此處執行一直報錯
@Update("UPDATE TREE SET TREE_STATE=#{treeState} WHERE TREE_ID=#{treeId}")
int updateState(final int treeId, final TreeState treeState);
@Delete("DELETE FROM TREE WHERE TREE_ID=#{treeId}")
int deleteTree(final int treeId);
@Results({
@Result(id = true, column = "TREE_ID",property = "treeId"),
@Result(column = "TREE_NAME",property = "treeName"),
@Result(column = "TREE_AGE", property = "treeAge"),
@Result(column = "TREE_HIGHT",property = "treeHight"),
@Result(column = "TREE_TYPE",property = "treeType",typeHandler = EnumOrdinalTypeHandler.class),
@Result(column = "TREE_STATE",property = "treeState",typeHandler = EnumOrdinalTypeHandler.class),
@Result(column = "TREE_DESC", property = "treeDesc")
})
@Select("SELECT * FROM TREE WHERE TREE_ID=#{treeId}")
Tree getTree(final int treeId);
@Results({
@Result(id = true, column = "TREE_ID",property = "treeId"),
@Result(column = "TREE_NAME",property = "treeName"),
@Result(column = "TREE_AGE", property = "treeAge"),
@Result(column = "TREE_HIGHT",property = "treeHight"),
@Result(column = "TREE_TYPE",property = "treeType",typeHandler = EnumOrdinalTypeHandler.class),
@Result(column = "TREE_STATE",property = "treeState",typeHandler = EnumOrdinalTypeHandler.class),
@Result(column = "TREE_DESC", property = "treeDesc")
})
@Select("SELECT * FROM TREE")
List<Tree> getTrees(RowBounds rowBounds);
}
注意：重點就在這個接口中，我們添加接口注解@Mapper，表示這是一個持久層Mapper,它的實例化依靠SpringBoot自動配置完成。
在接口方法上直接添加對應的執行注解，在注解中直接定義SQL，這種SQL仍然可以使用表達式#{}來獲取參數的值。
注意@Result注解中定義的兩個關於枚舉的類型處理器EnumOrdinalTypeHandler，其實其為MyBatis內部自帶的兩種枚舉處理器之一，
用於存儲枚舉序號，還有一個EnumTypeHandler用於存儲枚舉名稱。
第三步：定義service和controller
@Service
@Log4j2
public class TreeService {
@Autowired
private TreeRepository treeRepository;
public ResponseEntity<Tree> addTree(final Tree tree){
treeRepository.addTree(tree);
return ResponseEntity.ok(tree);
}
public ResponseEntity<Tree> updateTree(final int treeId, final TreeState treeState){
treeRepository.updateState(treeId,treeState);
return ResponseEntity.ok(Tree.builder().treeId(treeId).treeState(treeState).build());
}
public ResponseEntity<Integer> deleteTree(final int treeId){
return ResponseEntity.ok(treeRepository.deleteTree(treeId));
}
public ResponseEntity<Tree> getTree(final int treeId){
return ResponseEntity.ok(treeRepository.getTree(treeId));
}
public ResponseEntity<MyPage<Tree>> getTrees(final int pageId,final int pageSize){
List<Tree> trees = treeRepository.getTrees(new RowBounds(pageId,pageSize));
MyPage<Tree> treeMyPage = new MyPage<>();
treeMyPage.setPageId(pageId);
treeMyPage.setPageSize(pageSize);
treeMyPage.setBody(trees);
return ResponseEntity.ok(treeMyPage);
}
}
@RestController
@RequestMapping("/tree")
@Api(description = "樹木接口")
public class TreeApi {
@Autowired
private TreeService treeService;
@RequestMapping(value = "/addTree",method = RequestMethod.PUT)
@ApiOperation(value = "添加樹木",notes = "添加新樹木",httpMethod = "PUT")
public ResponseEntity<Tree> addTree(final Tree tree){
return treeService.addTree(tree);
}
@RequestMapping(value = "/updateTree",method = RequestMethod.POST)
@ApiOperation(value = "更新狀態",notes = "修改樹木狀態",httpMethod = "POST")
public ResponseEntity<Tree> updateTree(final int treeId,final TreeState treeState){
return treeService.updateTree(treeId,treeState);
}
@ApiOperation(value = "獲取樹木",notes = "根據ID獲取一棵樹",httpMethod = "GET")
@RequestMapping(value = "/getTree",method = RequestMethod.GET)
public ResponseEntity<Tree> getTree(final int treeId){
return treeService.getTree(treeId);
}
}
注意：這個例子中更新狀態的時候還是無法成功，這個狀態是枚舉值