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)
https://blog.csdn.net/m1729339749/article/details/133063604
这里我们直接使用脚本初始化数据库中的数据
- -- 如果数据库不存在则创建数据库
- CREATE DATABASE IF NOT EXISTS demo DEFAULT CHARSET utf8;
- -- 切换数据库
- USE demo;
- -- 创建用户表
- CREATE TABLE IF NOT EXISTS T_USER(
- ID INT PRIMARY KEY,
- USERNAME VARCHAR(32) NOT NULL,
- AGE INT NOT NULL
- );
- -- 插入用户数据
- INSERT INTO T_USER(ID, USERNAME, AGE)
- 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
在cn.horse.demo下创建UserInfo、UserInfoQuery类
UserInfo类:
- package cn.horse.demo;
-
- public class UserInfo {
-
- private Integer id;
- private String name;
- private Integer age;
-
- public void setId(Integer id) {
- this.id = id;
- }
-
- public Integer getId() {
- return id;
- }
-
- public void setName(String name) {
- this.name = name;
- }
-
- public String getName() {
- return name;
- }
-
- public void setAge(Integer age) {
- this.age = age;
- }
-
- public Integer getAge() {
- return age;
- }
-
- @Override
- public String toString() {
- StringBuilder stringBuilder = new StringBuilder();
- stringBuilder.append('{');
- stringBuilder.append("id: " + this.id);
- stringBuilder.append(", ");
- stringBuilder.append("name: " + this.name);
- stringBuilder.append(", ");
- stringBuilder.append("age: " + this.age);
- stringBuilder.append('}');
- return stringBuilder.toString();
- }
- }
UserInfoQuery类:
- package cn.horse.demo;
-
- public class UserInfoQuery {
-
- private Integer startAge;
- private Integer endAge;
-
- public void setStartAge(Integer startAge) {
- this.startAge = startAge;
- }
-
- public Integer getStartAge() {
- return startAge;
- }
-
- public void setEndAge(Integer endAge) {
- this.endAge = endAge;
- }
-
- public Integer getEndAge() {
- return endAge;
- }
- }
在cn.horse.demo下创建UserInfoMapper接口、UserInfoSqlProvider类
UserInfoMapper接口:
- package cn.horse.demo;
-
- import org.apache.ibatis.annotations.*;
-
- import java.util.List;
-
- public interface UserInfoMapper {
- }
UserInfoSqlProvider类:
- package cn.horse.demo;
-
- import org.apache.ibatis.annotations.Param;
-
- import java.util.*;
-
- public class UserInfoSqlProvider {
- }
在resources下新建mybatis-config.xml配置文件,并引入UserInfoMapper映射器。
- "1.0" encoding="UTF-8" ?>
- configuration
- PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
- "http://mybatis.org/dtd/mybatis-3-config.dtd">
- <configuration>
- <settings>
- <setting name="logImpl" value="JDK_LOGGING"/>
- settings>
-
- <environments default="development">
- <environment id="development">
- <transactionManager type="JDBC"/>
- <dataSource type="POOLED">
- <property name="driver" value="org.gjt.mm.mysql.Driver"/>
- <property name="url" value="jdbc:mysql://localhost:3306/demo?useUnicode=true&useSSL=false&characterEncoding=utf8"/>
- <property name="username" value="root"/>
- <property name="password" value="horse"/>
- dataSource>
- environment>
- environments>
-
- <mappers>
- <mapper class="cn.horse.demo.UserInfoMapper" />
- mappers>
- 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。
在cn.horse.demo包下新建SqlSessionUtils工具类
- package cn.horse.demo;
-
- import org.apache.ibatis.session.SqlSession;
- import org.apache.ibatis.session.SqlSessionFactory;
- import org.apache.ibatis.session.SqlSessionFactoryBuilder;
-
- import java.io.InputStream;
- import java.util.Objects;
-
- public class SqlSessionUtils {
-
- private static final SqlSessionFactory sqlSessionFactory;
- static {
- // 读取mybatis配置文件
- InputStream inputStream = ClassLoader.getSystemClassLoader().getResourceAsStream("mybatis-config.xml");
- // 根据配置创建SqlSession工厂
- sqlSessionFactory = new SqlSessionFactoryBuilder()
- .build(inputStream);
- }
-
- /**
- * 开启会话
- * @return
- */
- public static SqlSession openSession() {
- return sqlSessionFactory.openSession();
- }
-
- /**
- * 关闭会话
- * @param sqlSession
- */
- public static void closeSession(SqlSession sqlSession) {
- if(Objects.nonNull(sqlSession)) {
- sqlSession.close();
- }
- }
- }
在resources的目录下新建logging.properties配置文件
- handlers=java.util.logging.ConsoleHandler
- .level=INFO
-
- cn.horse.demo.UserInfoMapper.level=FINER
- java.util.logging.ConsoleHandler.level=ALL
- java.util.logging.ConsoleHandler.formatter=java.util.logging.SimpleFormatter
- 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:
- package cn.horse.demo;
-
- import java.io.IOException;
- import java.io.InputStream;
- import java.util.logging.LogManager;
-
- public class JdkLogConfig {
-
- public JdkLogConfig() {
- try {
- InputStream inputStream = ClassLoader.getSystemClassLoader().getResourceAsStream("logging.properties");
- LogManager.getLogManager().readConfiguration(inputStream);
- } catch (IOException e) {
- throw new RuntimeException(e);
- }
- }
- }
- package cn.horse.demo;
-
- import org.apache.ibatis.session.SqlSession;
-
- import java.util.List;
- import java.util.function.Consumer;
-
- public class Main {
- public static void main(String[] args) {
- // 引入JDK日志配置
- System.setProperty("java.util.logging.config.class", "cn.horse.demo.JdkLogConfig");
- }
-
- private static void execute(Consumer
function) { - SqlSession sqlSession = null;
- try {
- sqlSession = SqlSessionUtils.openSession();
- function.accept(sqlSession.getMapper(UserInfoMapper.class));
- sqlSession.commit();
- } finally {
- SqlSessionUtils.closeSession(sqlSession);
- }
- }
- }
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。
在UserInfoMapper映射器中新增find方法
- @SelectProvider(type = UserInfoSqlProvider.class, method = "select")
- 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
- public String select(@Param("query") UserInfoQuery query) {
- StringBuilder sqlBuilder = new StringBuilder();
- sqlBuilder.append("SELECT ID, USERNAME name, AGE FROM T_USER");
- // 获取条件语句
- List
conditionStmt = fetchConditionStatement(query); - if(!conditionStmt.isEmpty()) {
- sqlBuilder.append(" WHERE ");
- sqlBuilder.append(String.join(" AND ", conditionStmt));
- }
- return sqlBuilder.toString();
- }
-
- // 获取条件语句
- private List
fetchConditionStatement(UserInfoQuery query) { - if(Objects.isNull(query)
- || (Objects.isNull(query.getStartAge()) && Objects.isNull(query.getEndAge()))) {
- return Collections.emptyList();
- }
- List
conditionStmt = new ArrayList<>(2); - if(Objects.nonNull(query.getStartAge())) {
- conditionStmt.add("AGE >= #{query.startAge}");
- }
- if(Objects.nonNull(query.getEndAge())) {
- conditionStmt.add("AGE <= #{query.endAge}");
- }
- return conditionStmt;
- }
调用映射器中的find方法查询数据
- // 引入JDK日志配置
- System.setProperty("java.util.logging.config.class", "cn.horse.demo.JdkLogConfig");
-
- // 查询
- execute((UserInfoMapper userInfoMapper) -> {
- UserInfoQuery query = new UserInfoQuery();
- query.setEndAge(20);
- List
userInfoList = userInfoMapper.find(query); - for (UserInfo userInfo: userInfoList) {
- System.out.println(userInfo);
- }
- });
执行后的结果如下:

在UserInfoMapper映射器中新增insert方法
- @InsertProvider(type = UserInfoSqlProvider.class, method = "insert")
- 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
- public String insert(@Param("userInfoList") List
userInfoList) { - StringBuilder sqlBuilder = new StringBuilder("INSERT INTO T_USER(ID, USERNAME, AGE) VALUES");
- for (int i = 0; i < userInfoList.size(); i++) {
- sqlBuilder.append('(');
- sqlBuilder.append("#{userInfoList["+ i +"].id},");
- sqlBuilder.append("#{userInfoList["+ i +"].name},");
- sqlBuilder.append("#{userInfoList["+ i +"].age}");
- sqlBuilder.append(')');
- if(i != userInfoList.size() - 1) {
- sqlBuilder.append(',');
- }
- }
- return sqlBuilder.toString();
- }
调用映射器中的insert方法新增数据
- // 引入JDK日志配置
- System.setProperty("java.util.logging.config.class", "cn.horse.demo.JdkLogConfig");
-
- // 插入
- execute((UserInfoMapper userInfoMapper) -> {
- List
userInfoList = new ArrayList<>(); - UserInfo userInfo1 = new UserInfo();
- userInfo1.setId(5);
- userInfo1.setName("王五1");
- userInfo1.setAge(5);
- userInfoList.add(userInfo1);
- UserInfo userInfo2 = new UserInfo();
- userInfo2.setId(6);
- userInfo2.setName("王五2");
- userInfo2.setAge(6);
- userInfoList.add(userInfo2);
- Integer total = userInfoMapper.insert(userInfoList);
- System.out.println("插入条数: " + total);
- });
执行后的结果如下:

在UserInfoMapper映射器中新增update方法
- @UpdateProvider(type = UserInfoSqlProvider.class, method = "update")
- 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
- public String update(@Param("userInfoList") List
userInfoList) { - StringBuilder sqlBuilder = new StringBuilder();
-
- for (int i = 0; i < userInfoList.size(); i++) {
- sqlBuilder.append("UPDATE T_USER SET ");
-
- // 获取条件语句
- sqlBuilder.append(String.join(", ", fetchUpdateStatement(i, userInfoList.get(i))));
- sqlBuilder.append(" WHERE ID = #{userInfoList["+ i +"].id}");
- if(i != userInfoList.size() - 1) {
- sqlBuilder.append(';');
- }
- }
- return sqlBuilder.toString();
- }
-
- private List
fetchUpdateStatement(Integer i, UserInfo userInfo) { - if(Objects.isNull(userInfo)
- || (Objects.isNull(userInfo.getName()) && Objects.isNull(userInfo.getAge()))) {
- return Arrays.asList("ID = #{userInfoList["+ i +"].id}");
- }
- List
updateStmt = new ArrayList<>(2); - if(Objects.nonNull(userInfo.getName())) {
- updateStmt.add("USERNAME = #{userInfoList["+ i +"].name}");
- }
- if(Objects.nonNull(userInfo.getAge())) {
- updateStmt.add("AGE = #{userInfoList["+ i +"].age}");
- }
- return updateStmt;
- }
调用映射器中的update方法修改数据
- // 引入JDK日志配置
- System.setProperty("java.util.logging.config.class", "cn.horse.demo.JdkLogConfig");
-
- // 更新
- execute((UserInfoMapper userInfoMapper) -> {
- List
userInfoList = new ArrayList<>(); - UserInfo userInfo1 = new UserInfo();
- userInfo1.setId(5);
- userInfo1.setName("王五11");
- userInfoList.add(userInfo1);
- UserInfo userInfo2 = new UserInfo();
- userInfo2.setId(6);
- userInfo2.setAge(26);
- userInfoList.add(userInfo2);
- Integer total = userInfoMapper.update(userInfoList);
- System.out.println("更新条数: " + total);
- });
执行后的结果如下:

可能出现的问题:
- 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 = ?
- 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)
- Exception in thread "main" org.apache.ibatis.exceptions.PersistenceException:
- ### 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
- ### The error may involve cn.horse.demo.UserInfoMapper.update-Inline
- ### The error occurred while setting parameters
- ### SQL: UPDATE T_USER SET USERNAME = ? WHERE ID = ?;UPDATE T_USER SET AGE = ? WHERE ID = ?
- ### 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
- at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)
- at org.apache.ibatis.session.defaults.DefaultSqlSession.update(DefaultSqlSession.java:200)
- at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:62)
- at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:59)
- at jdk.proxy2/jdk.proxy2.$Proxy7.update(Unknown Source)
- at cn.horse.demo.Main.lambda$main$0(Main.java:59)
- at cn.horse.demo.Main.execute(Main.java:76)
- at cn.horse.demo.Main.main(Main.java:49)
- 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
- at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
- at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:77)
- at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
- at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:499)
- at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:480)
- at com.mysql.jdbc.Util.handleNewInstance(Util.java:403)
- at com.mysql.jdbc.Util.getInstance(Util.java:386)
- at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:944)
- at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3933)
- at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3869)
- at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2524)
- at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2675)
- at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2465)
- at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1915)
- at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:1254)
- at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
- at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
- at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
- at java.base/java.lang.reflect.Method.invoke(Method.java:568)
- at org.apache.ibatis.logging.jdbc.PreparedStatementLogger.invoke(PreparedStatementLogger.java:59)
- at jdk.proxy3/jdk.proxy3.$Proxy9.execute(Unknown Source)
- at org.apache.ibatis.executor.statement.PreparedStatementHandler.update(PreparedStatementHandler.java:46)
- at org.apache.ibatis.executor.statement.RoutingStatementHandler.update(RoutingStatementHandler.java:74)
- at org.apache.ibatis.executor.SimpleExecutor.doUpdate(SimpleExecutor.java:50)
- at org.apache.ibatis.executor.BaseExecutor.update(BaseExecutor.java:117)
- at org.apache.ibatis.executor.CachingExecutor.update(CachingExecutor.java:76)
- at org.apache.ibatis.session.defaults.DefaultSqlSession.update(DefaultSqlSession.java:198)
- ... 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:
- "1.0" encoding="UTF-8" ?>
- configuration
- PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
- "http://mybatis.org/dtd/mybatis-3-config.dtd">
- <configuration>
- <settings>
- <setting name="logImpl" value="JDK_LOGGING"/>
- settings>
-
- <environments default="development">
- <environment id="development">
- <transactionManager type="JDBC"/>
- <dataSource type="POOLED">
- <property name="driver" value="org.gjt.mm.mysql.Driver"/>
- <property name="url" value="jdbc:mysql://localhost:3306/demo?useUnicode=true&useSSL=false&characterEncoding=utf8&allowMultiQueries=true"/>
- <property name="username" value="root"/>
- <property name="password" value="horse"/>
- dataSource>
- environment>
- environments>
-
- <mappers>
- <mapper class="cn.horse.demo.UserInfoMapper" />
- mappers>
- 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
在UserInfoMapper映射器中新增delete方法
- @DeleteProvider(type = UserInfoSqlProvider.class, method = "delete")
- 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
- public String delete(@Param("idList") List
idList) { - StringBuilder sqlBuilder = new StringBuilder("DELETE FROM T_USER WHERE ID IN (");
- for (int i = 0; i < idList.size(); i++) {
- sqlBuilder.append("#{idList["+ i +"]}");
- if(i != idList.size() - 1) {
- sqlBuilder.append(',');
- }
- }
- sqlBuilder.append(')');
- return sqlBuilder.toString();
- }
调用映射器中的delete方法删除数据
- // 引入JDK日志配置
- System.setProperty("java.util.logging.config.class", "cn.horse.demo.JdkLogConfig");
-
- // 删除
- execute((UserInfoMapper userInfoMapper) -> {
- Integer total = userInfoMapper.delete(Arrays.asList(5, 6));
- System.out.println("删除条数: " + total);
- });
执行后的结果如下:
