概述
我们前面几篇文章,所列举的接口方法中只有一个参数,参数的类型可以分为两种
基本类型
当参数是一个基本类型的时候,它在XML文件中对应的SQL语句只会使用一个参数,比如delete方法
当参数类型是一个JavaBean类型的时候,它在XML文件中对应的SQL语句中会有多个参数,比如insert、update
在实际应用中使用多个参数的情况再常见不过来。前面的博文,我们有个方法是将多个参数合并到一个JavaBean中,并使用这个Bean作为接口方法的参数。这种方法虽然方便,单并不适合全部的情况,因为不可能只为了两三个参数去创建新的JavaBean。
因此对于参数比较少的情况,有两种方式可以采用
使用Map类型作为参数使用@Param注解
使用Map类型作为参数需要手工创建MAP并且对参数进行赋值,并不简洁。这里推荐使用@Param注解的方式
模拟场景:根据用户ID和角色的enable状态来查询用户的所有角色
工程结构
多个基本类型参数的场景
我们先来看下如果在接口中使用多个参数但不是用Param注解的情况
UserRoleMapper接口增加接口方法
package com.artisan.mybatis.xml.mapper;
import java.util.List;
import com.artisan.mybatis.xml.domain.SysRole;
public interface UserRoleMapper {
/**
*
*
* @Title: selectSysRolesByUserIdAndRoleEnable
*
* @Description: 根据用户ID和角色的Enable属性查询角色
*
* @param userId
* @param enable
* @return
*
* @return: List
*/
List selectSysRolesByUserIdAndRoleEnable(Long userId, Integer enable);
}
UserRoleMapper.xml配置查询语句
单元测试
package com.artisan.mybatis.xml.mapper;
import java.util.List;
import org.apache.ibatis.session.SqlSession;
import org.apache.log4j.Logger;
import org.junit.Assert;
import org.junit.Test;
import com.artisan.mybatis.xml.domain.SysRole;
/**
*
*
* @ClassName: UserRoleMapperTest
*
* @Description: UserRoleMapperTest测试类
*
* @author: Mr.Yang
*
* @date: 2018年4月16日 下午3:34:45
*/
public class UserRoleMapperTest extends BaseMapperTest {
private static final Logger logger = Logger.getLogger(UserRoleMapperTest.class);
private SqlSession sqlSession;
@Test
public void selectSysRolesByUserIdAndRoleEnableTest(){
logger.info('selectSysRolesByUserIdAndRoleEnableTest');
try {
// 获取SqlSession
sqlSession = getSqlSession();
// 获取UserRoleMapper
UserRoleMapper userRoleMapper = sqlSession.getMapper(UserRoleMapper.class);
// 通过接口调用方法
List roleList = userRoleMapper.selectSysRolesByUserIdAndRoleEnable((long) 1, 1);
// 期望roleList不为空
Assert.assertNotNull(roleList);
// 期望roleList> 0
Assert.assertTrue(roleList.size() > 0);
for (SysRole sysRole : roleList) {
logger.info(sysRole);
}
} catch (Exception e) {
e.printStackTrace();
}finally{
sqlSession.close();
logger.info('sqlSession close successfully ');
}
}
}
选中方法,执行单元测试
会得到如下异常
org.apache.ibatis.exceptions.PersistenceException:
### Error querying database. Cause: org.apache.ibatis.binding.BindingException: Parameter 'userId' not found. Available parameters are [1, 0, param1, param2]
### Cause: org.apache.ibatis.binding.BindingException: Parameter 'userId' not found. Available parameters are [1, 0, param1, param2]
at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:122)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:113)
at org.apache.ibatis.binding.MapperMethod.executeForMany(MapperMethod.java:122)
at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:64)
at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:53)
at com.sun.proxy.$Proxy6.selectSysRolesByUserIdAndRoleEnable(Unknown Source)
at com.artisan.mybatis.xml.mapper.UserRoleMapperTest.selectSysRolesByUserIdAndRoleEnableTest(UserRoleMapperTest.java:40)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
Caused by: org.apache.ibatis.binding.BindingException: Parameter 'userId' not found. Available parameters are [1, 0, param1, param2]
at org.apache.ibatis.binding.MapperMethod$ParamMap.get(MapperMethod.java:168)
at org.apache.ibatis.reflection.wrapper.MapWrapper.get(MapWrapper.java:45)
at org.apache.ibatis.reflection.MetaObject.getValue(MetaObject.java:122)
at org.apache.ibatis.executor.BaseExecutor.createCacheKey(BaseExecutor.java:212)
at org.apache.ibatis.executor.CachingExecutor.createCacheKey(CachingExecutor.java:139)
at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:81)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:120)
重点信息
### Cause: org.apache.ibatis.binding.BindingException: Parameter 'userId' not found. Available parameters are [1, 0, param1, param2]
这个错误标识,xml可用的参数只有0、paramparam2,没有userI
,0,param1,param2都是Mybatis根据参数位置自定义的名字,如果将xml中的#{userId}改为#{0}或者#{param1},将#{enbale}改为#{1}或者#{param2},这个方法是可以被正常调用的。这里只是为了演示,实际上并不建议这么做。
修复
现在在接口方法的参数前添加@Param注解
package com.artisan.mybatis.xml.mapper;
import java.util.List;
import org.apache.ibatis.annotations.Param;
import com.artisan.mybatis.xml.domain.SysRole;
public interface UserRoleMapper {
/**
*
*
* @Title: selectSysRolesByUserIdAndRoleEnable
*
* @Description: 根据用户ID和角色的Enable属性查询角色
*
* @param userId
* @param enable
* @return
*
* @return: List
*/
List selectSysRolesByUserIdAndRoleEnable(@Param('userId') Long userId, @Param('enable') Integer enable);
}
重新运行单元测试
2018-04-16 19:43:22,404 INFO [main] (BaseMapperTest.java:26) - sessionFactory bulit successfully
2018-04-16 19:43:22,408 INFO [main] (BaseMapperTest.java:29) - reader close successfully
2018-04-16 19:43:22,412 INFO [main] (UserRoleMapperTest.java:31) - selectSysRolesByUserIdAndRoleEnableTest
2018-04-16 19:43:22,910 DEBUG [main] (BaseJdbcLogger.java:142) - ==> Preparing: SELECT c.id, c.role_name roleName, c.enabled, c.create_by createBy, c.create_time createTime FROM sys_user a INNER JOIN sys_user_role b ON a.id = b.user_id INNER JOIN sys_role c ON b.role_id = c.id WHERE a.id = ? AND c.enabled = ?
2018-04-16 19:43:22,988 DEBUG [main] (BaseJdbcLogger.java:142) - ==> Parameters: 1(Long), 1(Integer)
2018-04-16 19:43:23,025 TRACE [main] (BaseJdbcLogger.java:148) - <== Columns: id, roleName, enabled, createBy, createTime
2018-04-16 19:43:23,026 TRACE [main] (BaseJdbcLogger.java:148) - <== Row: 1, 管理员, 1, 1, 2018-04-13 21:12:46.0
2018-04-16 19:43:23,031 TRACE [main] (BaseJdbcLogger.java:148) - <== Row: 2, 普通用户, 1, 1, 2018-04-13 21:12:46.0
2018-04-16 19:43:23,032 DEBUG [main] (BaseJdbcLogger.java:142) - <== Total: 2
2018-04-16 19:43:23,033 INFO [main] (UserRoleMapperTest.java:48) - SysRole [id=1, roleName=管理员, enabled=1, createBy=1, createTime=Fri Apr 13 21:12:46 BOT 2018, user=null, privilegeList=null]
2018-04-16 19:43:23,037 INFO [main] (UserRoleMapperTest.java:48) - SysRole [id=2, roleName=普通用户, enabled=1, createBy=1, createTime=Fri Apr 13 21:12:46 BOT 2018, user=null, privilegeList=null]
2018-04-16 19:43:23,039 INFO [main] (UserRoleMapperTest.java:54) - sqlSession close successfully
测试通过了,这时的XML文件中对应的SQL的可用参数变成了【userId,enable,param1,param2】,如果#{userId}改为#{param1},将#{enbale}改为#{param2}也是可以通过的。
给参数配置@Param注解后,mybatis就会自动将参数封装成Map类型,@Param注解值会作为Map的key因此在SQL部分就会通过配置的注解值来使用参数。
多个参数为JavaBean类型场景
UserRoleMapper接口增加接口方法
// 传递多个JavaBean的场景
List selectSysRolesByUserIdAndRoleEnable2(@Param('sysUser') SysUser sysUser, @Param('sysRole') SysRole sysRole);
这个时候,在XML中就不能直接使用#{userId}和#{enabled}了,而是要通过点取值方式使用#{sysUser.id}和#{sysRolenabled}从两个JavaBean中取出指定属性的值。
单元测试
@Test
public void selectSysRolesByUserIdAndRoleEnable2Test() {
logger.info('selectSysRolesByUserIdAndRoleEnable2Test');
try {
// 获取SqlSession
sqlSession = getSqlSession();
// 获取UserRoleMapper
UserRoleMapper userRoleMapper = sqlSession.getMapper(UserRoleMapper.class);
// 构造SysUser
SysUser sysUser = new SysUser();
sysUser.setId((long) 1);
// 构造SysRole
SysRole sysRole = new SysRole();
sysRole.setEnabled(1);
// 通过接口调用方法
List roleList = userRoleMapper.selectSysRolesByUserIdAndRoleEnable2(sysUser, sysRole);
// 期望roleList不为空
Assert.assertNotNull(roleList);
// 期望roleList> 0
Assert.assertTrue(roleList.size() > 0);
for (SysRole sysRole2 : roleList) {
logger.info(sysRole2);
}
} catch (Exception e) {
e.printStackTrace();
}finally{
sqlSession.close();
logger.info('sqlSession close successfully ');
}
}
日志
2018-04-16 20:13:06,731 INFO [main] (BaseMapperTest.java:26) - sessionFactory bulit successfully
2018-04-16 20:13:06,734 INFO [main] (BaseMapperTest.java:29) - reader close successfully
2018-04-16 20:13:06,738 INFO [main] (UserRoleMapperTest.java:62) - selectSysRolesByUserIdAndRoleEnable2Test
2018-04-16 20:13:07,361 DEBUG [main] (BaseJdbcLogger.java:142) - ==> Preparing: SELECT c.id, c.role_name roleName, c.enabled, c.create_by createBy, c.create_time createTime FROM sys_user a INNER JOIN sys_user_role b ON a.id = b.user_id INNER JOIN sys_role c ON b.role_id = c.id WHERE a.id = ? AND c.enabled = ?
2018-04-16 20:13:07,449 DEBUG [main] (BaseJdbcLogger.java:142) - ==> Parameters: 1(Long), 1(Integer)
2018-04-16 20:13:07,483 TRACE [main] (BaseJdbcLogger.java:148) - <== Columns: id, roleName, enabled, createBy, createTime
2018-04-16 20:13:07,484 TRACE [main] (BaseJdbcLogger.java:148) - <== Row: 1, 管理员, 1, 1, 2018-04-13 21:12:46.0
2018-04-16 20:13:07,487 TRACE [main] (BaseJdbcLogger.java:148) - <== Row: 2, 普通用户, 1, 1, 2018-04-13 21:12:46.0
2018-04-16 20:13:07,488 DEBUG [main] (BaseJdbcLogger.java:142) - <== Total: 2
2018-04-16 20:13:07,489 INFO [main] (UserRoleMapperTest.java:86) - SysRole [id=1, roleName=管理员, enabled=1, createBy=1, createTime=Fri Apr 13 21:12:46 BOT 2018, user=null, privilegeList=null]
2018-04-16 20:13:07,494 INFO [main] (UserRoleMapperTest.java:86) - SysRole [id=2, roleName=普通用户, enabled=1, createBy=1, createTime=Fri Apr 13 21:12:46 BOT 2018, user=null, privilegeList=null]
2018-04-16 20:13:07,495 INFO [main] (UserRoleMapperTest.java:92) - sqlSession close successfully
小结
除了上述常用的类型,接口的参数还可以是集合或者数组,后续介绍。
文章为作者独立观点,不代表 股票程序化软件自动交易接口观点