• Mybatis 映射器中使用@InsertProvider,@UpdateProvider,@DeleteProvider,@SelectProvider


    上一篇我们介绍了在Mybatis映射器的映射方法中使用@Param接收多个参数;本篇我们继续介绍如何在Mybatis的映射器中使用动态SQL。

    如果您对Mybatis映射器的映射方法中使用@Param接收多个参数不太了解,建议您先进行了解后再阅读本篇,可以参考:

    Mybatis 映射器中映射方法接受多个参数(@Param)icon-default.png?t=N7T8https://blog.csdn.net/m1729339749/article/details/133063604

    一、数据准备

    这里我们直接使用脚本初始化数据库中的数据

    1. -- 如果数据库不存在则创建数据库
    2. CREATE DATABASE IF NOT EXISTS demo DEFAULT CHARSET utf8;
    3. -- 切换数据库
    4. USE demo;
    5. -- 创建用户表
    6. CREATE TABLE IF NOT EXISTS T_USER(
    7. ID INT PRIMARY KEY,
    8. USERNAME VARCHAR(32) NOT NULL,
    9. AGE INT NOT NULL
    10. );
    11. -- 插入用户数据
    12. INSERT INTO T_USER(ID, USERNAME, AGE)
    13. VALUES(1, '张三', 20),(2, '李四', 22),(3, '王五', 24);

    创建了一个名称为demo的数据库;并在库里创建了名称为T_USER的用户表并向表中插入了数据

    二、创建实体类

    在cn.horse.demo下创建UserInfo、UserInfoQuery类

    UserInfo类:

    1. package cn.horse.demo;
    2. public class UserInfo {
    3. private Integer id;
    4. private String name;
    5. private Integer age;
    6. public void setId(Integer id) {
    7. this.id = id;
    8. }
    9. public Integer getId() {
    10. return id;
    11. }
    12. public void setName(String name) {
    13. this.name = name;
    14. }
    15. public String getName() {
    16. return name;
    17. }
    18. public void setAge(Integer age) {
    19. this.age = age;
    20. }
    21. public Integer getAge() {
    22. return age;
    23. }
    24. @Override
    25. public String toString() {
    26. StringBuilder stringBuilder = new StringBuilder();
    27. stringBuilder.append('{');
    28. stringBuilder.append("id: " + this.id);
    29. stringBuilder.append(", ");
    30. stringBuilder.append("name: " + this.name);
    31. stringBuilder.append(", ");
    32. stringBuilder.append("age: " + this.age);
    33. stringBuilder.append('}');
    34. return stringBuilder.toString();
    35. }
    36. }

    UserInfoQuery类:

    1. package cn.horse.demo;
    2. public class UserInfoQuery {
    3. private Integer startAge;
    4. private Integer endAge;
    5. public void setStartAge(Integer startAge) {
    6. this.startAge = startAge;
    7. }
    8. public Integer getStartAge() {
    9. return startAge;
    10. }
    11. public void setEndAge(Integer endAge) {
    12. this.endAge = endAge;
    13. }
    14. public Integer getEndAge() {
    15. return endAge;
    16. }
    17. }

    三、创建UserInfoMapper映射器、UserInfoSqlProvider类

    在cn.horse.demo下创建UserInfoMapper接口、UserInfoSqlProvider类

    UserInfoMapper接口:

    1. package cn.horse.demo;
    2. import org.apache.ibatis.annotations.*;
    3. import java.util.List;
    4. public interface UserInfoMapper {
    5. }

    UserInfoSqlProvider类:

    1. package cn.horse.demo;
    2. import org.apache.ibatis.annotations.Param;
    3. import java.util.*;
    4. public class UserInfoSqlProvider {
    5. }

    四、引入配置文件

    在resources下新建mybatis-config.xml配置文件,并引入UserInfoMapper映射器。

    1. "1.0" encoding="UTF-8" ?>
    2. configuration
    3. PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
    4. "http://mybatis.org/dtd/mybatis-3-config.dtd">
    5. <configuration>
    6. <settings>
    7. <setting name="logImpl" value="JDK_LOGGING"/>
    8. settings>
    9. <environments default="development">
    10. <environment id="development">
    11. <transactionManager type="JDBC"/>
    12. <dataSource type="POOLED">
    13. <property name="driver" value="org.gjt.mm.mysql.Driver"/>
    14. <property name="url" value="jdbc:mysql://localhost:3306/demo?useUnicode=true&useSSL=false&characterEncoding=utf8"/>
    15. <property name="username" value="root"/>
    16. <property name="password" value="horse"/>
    17. dataSource>
    18. environment>
    19. environments>
    20. <mappers>
    21. <mapper class="cn.horse.demo.UserInfoMapper" />
    22. mappers>
    23. configuration>

    这里我们使用mapper引入映射器,只需要设置class属性为UserInfoMapper接口的全限类名。

    五、启动程序配置

    1、会话工具类

    在cn.horse.demo包下新建SqlSessionUtils工具类

    1. package cn.horse.demo;
    2. import org.apache.ibatis.session.SqlSession;
    3. import org.apache.ibatis.session.SqlSessionFactory;
    4. import org.apache.ibatis.session.SqlSessionFactoryBuilder;
    5. import java.io.InputStream;
    6. import java.util.Objects;
    7. public class SqlSessionUtils {
    8. private static final SqlSessionFactory sqlSessionFactory;
    9. static {
    10. // 读取mybatis配置文件
    11. InputStream inputStream = ClassLoader.getSystemClassLoader().getResourceAsStream("mybatis-config.xml");
    12. // 根据配置创建SqlSession工厂
    13. sqlSessionFactory = new SqlSessionFactoryBuilder()
    14. .build(inputStream);
    15. }
    16. /**
    17. * 开启会话
    18. * @return
    19. */
    20. public static SqlSession openSession() {
    21. return sqlSessionFactory.openSession();
    22. }
    23. /**
    24. * 关闭会话
    25. * @param sqlSession
    26. */
    27. public static void closeSession(SqlSession sqlSession) {
    28. if(Objects.nonNull(sqlSession)) {
    29. sqlSession.close();
    30. }
    31. }
    32. }

    2、JDK 日志系统配置

    在resources的目录下新建logging.properties配置文件

    1. handlers=java.util.logging.ConsoleHandler
    2. .level=INFO
    3. cn.horse.demo.UserInfoMapper.level=FINER
    4. java.util.logging.ConsoleHandler.level=ALL
    5. java.util.logging.ConsoleHandler.formatter=java.util.logging.SimpleFormatter
    6. java.util.logging.SimpleFormatter.format=%1$tY-%1$tm-%1$td %1$tT.%1$tL %4$s %3$s - %5$s%6$s%n

    在cn.horse.demo下创建JdkLogConfig类

    JdkLogConfig类:

    1. package cn.horse.demo;
    2. import java.io.IOException;
    3. import java.io.InputStream;
    4. import java.util.logging.LogManager;
    5. public class JdkLogConfig {
    6. public JdkLogConfig() {
    7. try {
    8. InputStream inputStream = ClassLoader.getSystemClassLoader().getResourceAsStream("logging.properties");
    9. LogManager.getLogManager().readConfiguration(inputStream);
    10. } catch (IOException e) {
    11. throw new RuntimeException(e);
    12. }
    13. }
    14. }

    3、启动程序配置

    1. package cn.horse.demo;
    2. import org.apache.ibatis.session.SqlSession;
    3. import java.util.List;
    4. import java.util.function.Consumer;
    5. public class Main {
    6. public static void main(String[] args) {
    7. // 引入JDK日志配置
    8. System.setProperty("java.util.logging.config.class", "cn.horse.demo.JdkLogConfig");
    9. }
    10. private static void execute(Consumer function) {
    11. SqlSession sqlSession = null;
    12. try {
    13. sqlSession = SqlSessionUtils.openSession();
    14. function.accept(sqlSession.getMapper(UserInfoMapper.class));
    15. sqlSession.commit();
    16. } finally {
    17. SqlSessionUtils.closeSession(sqlSession);
    18. }
    19. }
    20. }

    execute方法用于执行操作,方法中使用sqlSession.getMapper方法获取映射器对象,然后将映射器对象具体的执行操作委托给了Consumer对象。

    六、查询数据

    在UserInfoMapper映射器中新增find方法

    1. @SelectProvider(type = UserInfoSqlProvider.class, method = "select")
    2. List find(@Param("query") UserInfoQuery query);

    使用SelectProvider注解,将查询语句的提供者配置成UserInfoSqlProvider的select方法,保证find方法的参数与UserInfoSqlProvider的select方法的参数保持一致(包括@Param注解),以避免出现问题。

    在UserInfoSqlProvider中新增select方法

    1. public String select(@Param("query") UserInfoQuery query) {
    2. StringBuilder sqlBuilder = new StringBuilder();
    3. sqlBuilder.append("SELECT ID, USERNAME name, AGE FROM T_USER");
    4. // 获取条件语句
    5. List conditionStmt = fetchConditionStatement(query);
    6. if(!conditionStmt.isEmpty()) {
    7. sqlBuilder.append(" WHERE ");
    8. sqlBuilder.append(String.join(" AND ", conditionStmt));
    9. }
    10. return sqlBuilder.toString();
    11. }
    12. // 获取条件语句
    13. private List fetchConditionStatement(UserInfoQuery query) {
    14. if(Objects.isNull(query)
    15. || (Objects.isNull(query.getStartAge()) && Objects.isNull(query.getEndAge()))) {
    16. return Collections.emptyList();
    17. }
    18. List conditionStmt = new ArrayList<>(2);
    19. if(Objects.nonNull(query.getStartAge())) {
    20. conditionStmt.add("AGE >= #{query.startAge}");
    21. }
    22. if(Objects.nonNull(query.getEndAge())) {
    23. conditionStmt.add("AGE <= #{query.endAge}");
    24. }
    25. return conditionStmt;
    26. }

    调用映射器中的find方法查询数据

    1. // 引入JDK日志配置
    2. System.setProperty("java.util.logging.config.class", "cn.horse.demo.JdkLogConfig");
    3. // 查询
    4. execute((UserInfoMapper userInfoMapper) -> {
    5. UserInfoQuery query = new UserInfoQuery();
    6. query.setEndAge(20);
    7. List userInfoList = userInfoMapper.find(query);
    8. for (UserInfo userInfo: userInfoList) {
    9. System.out.println(userInfo);
    10. }
    11. });

    执行后的结果如下:

    七、批量新增数据

    在UserInfoMapper映射器中新增insert方法

    1. @InsertProvider(type = UserInfoSqlProvider.class, method = "insert")
    2. Integer insert(@Param("userInfoList") List userInfoList);

    使用InsertProvider注解,将新增语句的提供者配置成UserInfoSqlProvider的insert方法,保证insert方法的参数与UserInfoSqlProvider的insert方法的参数保持一致(包括@Param注解),以避免出现问题。

    在UserInfoSqlProvider中新增insert方法

    1. public String insert(@Param("userInfoList") List userInfoList) {
    2. StringBuilder sqlBuilder = new StringBuilder("INSERT INTO T_USER(ID, USERNAME, AGE) VALUES");
    3. for (int i = 0; i < userInfoList.size(); i++) {
    4. sqlBuilder.append('(');
    5. sqlBuilder.append("#{userInfoList["+ i +"].id},");
    6. sqlBuilder.append("#{userInfoList["+ i +"].name},");
    7. sqlBuilder.append("#{userInfoList["+ i +"].age}");
    8. sqlBuilder.append(')');
    9. if(i != userInfoList.size() - 1) {
    10. sqlBuilder.append(',');
    11. }
    12. }
    13. return sqlBuilder.toString();
    14. }

    调用映射器中的insert方法新增数据

    1. // 引入JDK日志配置
    2. System.setProperty("java.util.logging.config.class", "cn.horse.demo.JdkLogConfig");
    3. // 插入
    4. execute((UserInfoMapper userInfoMapper) -> {
    5. List userInfoList = new ArrayList<>();
    6. UserInfo userInfo1 = new UserInfo();
    7. userInfo1.setId(5);
    8. userInfo1.setName("王五1");
    9. userInfo1.setAge(5);
    10. userInfoList.add(userInfo1);
    11. UserInfo userInfo2 = new UserInfo();
    12. userInfo2.setId(6);
    13. userInfo2.setName("王五2");
    14. userInfo2.setAge(6);
    15. userInfoList.add(userInfo2);
    16. Integer total = userInfoMapper.insert(userInfoList);
    17. System.out.println("插入条数: " + total);
    18. });

    执行后的结果如下:

    八、批量修改数据

    在UserInfoMapper映射器中新增update方法

    1. @UpdateProvider(type = UserInfoSqlProvider.class, method = "update")
    2. Integer update(@Param("userInfoList") List userInfoList);

    使用UpdateProvider注解,将更新语句的提供者配置成UserInfoSqlProvider的update方法,保证update方法的参数与UserInfoSqlProvider的update方法的参数保持一致(包括@Param注解),以避免出现问题。

    在UserInfoSqlProvider中新增update方法

    1. public String update(@Param("userInfoList") List userInfoList) {
    2. StringBuilder sqlBuilder = new StringBuilder();
    3. for (int i = 0; i < userInfoList.size(); i++) {
    4. sqlBuilder.append("UPDATE T_USER SET ");
    5. // 获取条件语句
    6. sqlBuilder.append(String.join(", ", fetchUpdateStatement(i, userInfoList.get(i))));
    7. sqlBuilder.append(" WHERE ID = #{userInfoList["+ i +"].id}");
    8. if(i != userInfoList.size() - 1) {
    9. sqlBuilder.append(';');
    10. }
    11. }
    12. return sqlBuilder.toString();
    13. }
    14. private List fetchUpdateStatement(Integer i, UserInfo userInfo) {
    15. if(Objects.isNull(userInfo)
    16. || (Objects.isNull(userInfo.getName()) && Objects.isNull(userInfo.getAge()))) {
    17. return Arrays.asList("ID = #{userInfoList["+ i +"].id}");
    18. }
    19. List updateStmt = new ArrayList<>(2);
    20. if(Objects.nonNull(userInfo.getName())) {
    21. updateStmt.add("USERNAME = #{userInfoList["+ i +"].name}");
    22. }
    23. if(Objects.nonNull(userInfo.getAge())) {
    24. updateStmt.add("AGE = #{userInfoList["+ i +"].age}");
    25. }
    26. return updateStmt;
    27. }

    调用映射器中的update方法修改数据

    1. // 引入JDK日志配置
    2. System.setProperty("java.util.logging.config.class", "cn.horse.demo.JdkLogConfig");
    3. // 更新
    4. execute((UserInfoMapper userInfoMapper) -> {
    5. List userInfoList = new ArrayList<>();
    6. UserInfo userInfo1 = new UserInfo();
    7. userInfo1.setId(5);
    8. userInfo1.setName("王五11");
    9. userInfoList.add(userInfo1);
    10. UserInfo userInfo2 = new UserInfo();
    11. userInfo2.setId(6);
    12. userInfo2.setAge(26);
    13. userInfoList.add(userInfo2);
    14. Integer total = userInfoMapper.update(userInfoList);
    15. System.out.println("更新条数: " + total);
    16. });

    执行后的结果如下:

    可能出现的问题:

    1. 2023-09-15 14:18:10.601 详细 cn.horse.demo.UserInfoMapper.update - ==> Preparing: UPDATE T_USER SET USERNAME = ? WHERE ID = ?;UPDATE T_USER SET AGE = ? WHERE ID = ?
    2. 2023-09-15 14:18:10.641 详细 cn.horse.demo.UserInfoMapper.update - ==> Parameters: 王五11(String), 5(Integer), 26(Integer), 6(Integer)
    3. Exception in thread "main" org.apache.ibatis.exceptions.PersistenceException:
    4. ### Error updating database. Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'UPDATE T_USER SET AGE = 26 WHERE ID = 6' at line 1
    5. ### The error may involve cn.horse.demo.UserInfoMapper.update-Inline
    6. ### The error occurred while setting parameters
    7. ### SQL: UPDATE T_USER SET USERNAME = ? WHERE ID = ?;UPDATE T_USER SET AGE = ? WHERE ID = ?
    8. ### Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'UPDATE T_USER SET AGE = 26 WHERE ID = 6' at line 1
    9. at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)
    10. at org.apache.ibatis.session.defaults.DefaultSqlSession.update(DefaultSqlSession.java:200)
    11. at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:62)
    12. at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:59)
    13. at jdk.proxy2/jdk.proxy2.$Proxy7.update(Unknown Source)
    14. at cn.horse.demo.Main.lambda$main$0(Main.java:59)
    15. at cn.horse.demo.Main.execute(Main.java:76)
    16. at cn.horse.demo.Main.main(Main.java:49)
    17. Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'UPDATE T_USER SET AGE = 26 WHERE ID = 6' at line 1
    18. at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    19. at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:77)
    20. at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    21. at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:499)
    22. at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:480)
    23. at com.mysql.jdbc.Util.handleNewInstance(Util.java:403)
    24. at com.mysql.jdbc.Util.getInstance(Util.java:386)
    25. at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:944)
    26. at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3933)
    27. at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3869)
    28. at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2524)
    29. at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2675)
    30. at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2465)
    31. at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1915)
    32. at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:1254)
    33. at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    34. at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
    35. at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    36. at java.base/java.lang.reflect.Method.invoke(Method.java:568)
    37. at org.apache.ibatis.logging.jdbc.PreparedStatementLogger.invoke(PreparedStatementLogger.java:59)
    38. at jdk.proxy3/jdk.proxy3.$Proxy9.execute(Unknown Source)
    39. at org.apache.ibatis.executor.statement.PreparedStatementHandler.update(PreparedStatementHandler.java:46)
    40. at org.apache.ibatis.executor.statement.RoutingStatementHandler.update(RoutingStatementHandler.java:74)
    41. at org.apache.ibatis.executor.SimpleExecutor.doUpdate(SimpleExecutor.java:50)
    42. at org.apache.ibatis.executor.BaseExecutor.update(BaseExecutor.java:117)
    43. at org.apache.ibatis.executor.CachingExecutor.update(CachingExecutor.java:76)
    44. at org.apache.ibatis.session.defaults.DefaultSqlSession.update(DefaultSqlSession.java:198)
    45. ... 6 more

    从上面执行的情况来看,SQL执行过程中报错了,原因是我们批量更新使用的是同时执行多条更新语句,而JDBC是不支持的;

    解决办法:

    在JDBC连接中添加连接属性allowMultiQueries=true

    修改mybatis-config.xml配置文件:

    1. "1.0" encoding="UTF-8" ?>
    2. configuration
    3. PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
    4. "http://mybatis.org/dtd/mybatis-3-config.dtd">
    5. <configuration>
    6. <settings>
    7. <setting name="logImpl" value="JDK_LOGGING"/>
    8. settings>
    9. <environments default="development">
    10. <environment id="development">
    11. <transactionManager type="JDBC"/>
    12. <dataSource type="POOLED">
    13. <property name="driver" value="org.gjt.mm.mysql.Driver"/>
    14. <property name="url" value="jdbc:mysql://localhost:3306/demo?useUnicode=true&useSSL=false&characterEncoding=utf8&allowMultiQueries=true"/>
    15. <property name="username" value="root"/>
    16. <property name="password" value="horse"/>
    17. dataSource>
    18. environment>
    19. environments>
    20. <mappers>
    21. <mapper class="cn.horse.demo.UserInfoMapper" />
    22. mappers>
    23. configuration>

    在配置文件中我们仅修改了

    jdbc:mysql://localhost:3306/demo?useUnicode=true&useSSL=false&characterEncoding=utf8&allowMultiQueries=true

    九、批量删除数据

    在UserInfoMapper映射器中新增delete方法

    1. @DeleteProvider(type = UserInfoSqlProvider.class, method = "delete")
    2. Integer delete(@Param("idList") List idList);

    使用DeleteProvider注解,将更新语句的提供者配置成UserInfoSqlProvider的delete方法,保证delete方法的参数与UserInfoSqlProvider的delete方法的参数保持一致(包括@Param注解),以避免出现问题。

    在UserInfoSqlProvider中新增delete方法

    1. public String delete(@Param("idList") List idList) {
    2. StringBuilder sqlBuilder = new StringBuilder("DELETE FROM T_USER WHERE ID IN (");
    3. for (int i = 0; i < idList.size(); i++) {
    4. sqlBuilder.append("#{idList["+ i +"]}");
    5. if(i != idList.size() - 1) {
    6. sqlBuilder.append(',');
    7. }
    8. }
    9. sqlBuilder.append(')');
    10. return sqlBuilder.toString();
    11. }

    调用映射器中的delete方法删除数据

    1. // 引入JDK日志配置
    2. System.setProperty("java.util.logging.config.class", "cn.horse.demo.JdkLogConfig");
    3. // 删除
    4. execute((UserInfoMapper userInfoMapper) -> {
    5. Integer total = userInfoMapper.delete(Arrays.asList(5, 6));
    6. System.out.println("删除条数: " + total);
    7. });

    执行后的结果如下:

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  • 原文地址:https://blog.csdn.net/m1729339749/article/details/133122304