MyBatis-06 MyBatis XML方式之多個介面引數用法
阿新 • • 發佈：2019-01-28
概述
我們前面幾篇文章，所列舉的介面方法中只有一個引數，引數的型別可以分為兩種
1. 基本型別
2. JavaBean
當引數是一個基本型別的時候，它在XML檔案中對應的SQL語句只會使用一個引數，比如delete方法
當引數型別是一個JavaBean型別的時候，它在XML檔案中對應的SQL語句中會有多個引數，比如 insert 、 update
在實際應用中使用多個引數的情況再常見不過來。 前面的博文，我們有個方法是將多個引數合併到一個JavaBean中，並使用這個Bean作為介面方法的引數。 這種方法雖然方便，單並不適合全部的情況，因為不可能只為了兩三個引數去建立新的JavaBean。
因此對於引數比較少的情況，有兩種方式可以採用
- 使用Map型別作為引數
- 使用@Param註解
使用Map型別作為引數需要手工建立MAP並且對引數進行賦值，並不簡潔。這裡推薦使用@Param註解的方式
模擬場景:根據使用者ID和角色的enable狀態來查詢使用者的所有角色
工程結構
多個基本型別引數的場景
我們先來看下如果在介面中使用多個引數但不是用Param註解的情況
1.UserRoleMapper介面增加介面方法
package com.artisan.mybatis.xml.mapper;
import java.util.List;
import 2.UserRoleMapper.xml配置查詢語句
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<!-- 當Mapper介面和XML檔案關聯的時候， namespace的值就需要配置成介面的全限定名稱 -->
<mapper namespace="com.artisan.mybatis.xml.mapper.UserRoleMapper">
<select
id="selectSysRolesByUserIdAndRoleEnable"
resultType="com.artisan.mybatis.xml.domain.SysRole">
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 = #{userId}
AND c.enabled = #{enabled}
</select>
</mapper> 3.單元測試
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測試類
*
* @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 {
// 獲取SqlSession
sqlSession = getSqlSession();
// 獲取UserRoleMapper
UserRoleMapper userRoleMapper = sqlSession.getMapper(UserRoleMapper.class);
// 通過介面呼叫方法
List<SysRole> roleList = userRoleMapper.selectSysRolesByUserIdAndRoleEnable((long) 1, 1);
// 期望roleList不為空
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 ");
}
}
}
選中方法，執行單元測試
會得到如下異常
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)重點資訊
### Cause: org.apache.ibatis.binding.BindingException: Parameter 'userId' not found. Available parameters are [1, 0, param1, param2]這個錯誤標識，xml可用的引數只有 0、1、param1、param2 , 沒有userId.
1, 0, param1, param2 都是Mybatis根據引數位置自定義的名字，如果將xml中的#{userId} 改為#{0}或者#{param1} ，將#{enbale}改為#{1}或者#{param2} ，這個方法是可以被正常呼叫的 。 這裡只是為了演示，實際上並不建議這麼做。
修復
現在在介面方法的引數前新增@Param註解
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: 根據使用者ID和角色的Enable屬性查詢角色
*
* @param userId
* @param enable
* @return
*
* @return: List<SysRole>
*/
List<SysRole> selectSysRolesByUserIdAndRoleEnable(@Param("userId") Long userId, @Param("enable") Integer enable);
}
重新執行單元測試
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, 管理員, 1, 1, 2018-04-13 21:12:46.0
2018-04-16 19:43:23,031 TRACE [main] (BaseJdbcLogger.java:148) - <== Row: 2, 普通使用者, 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=管理員, 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=普通使用者, 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
測試通過了，這時的XML檔案中對應的SQL的可用引數變成了【userId，enable，param1,param2】 ,如果#{userId} 改為#{param1} ，將#{enbale}改為#{param2}也是可以通過的。
給引數配置@Param註解後，mybatis就會自動將引數封裝成Map型別，@Param註解值會作為Map的key 因此在SQL部分就會通過配置的註解值來使用引數。
多個引數為JavaBean型別場景
1. UserRoleMapper介面增加介面方法
// 傳遞多個JavaBean的場景
List<SysRole> selectSysRolesByUserIdAndRoleEnable2(@Param("sysUser") SysUser sysUser, @Param("sysRole") SysRole sysRole);這個時候，在XML中就不能直接使用#{userId}和#{enabled}了，而是要通過點取值方式使用 #{sysUser.id} 和 #{sysRole.enabled} 從兩個JavaBean中取出指定屬性的值。
2.UserRoleMapper.xml配置SQL
<!-- 傳遞多個Bean的場景 -->
<select
id="selectSysRolesByUserIdAndRoleEnable2"
resultType="com.artisan.mybatis.xml.domain.SysRole">
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 = #{sysUser.id}
AND c.enabled = #{sysRole.enabled}
</select>3.單元測試
@Test
public void selectSysRolesByUserIdAndRoleEnable2Test() {
logger.info("selectSysRolesByUserIdAndRoleEnable2Test");
try {
// 獲取SqlSession
sqlSession = getSqlSession();
// 獲取UserRoleMapper
UserRoleMapper userRoleMapper = sqlSession.getMapper(UserRoleMapper.class);
// 構造SysUser
SysUser sysUser = new SysUser();
sysUser.setId((long) 1);
// 構造SysRole
SysRole sysRole = new SysRole();
sysRole.setEnabled(1);
// 通過介面呼叫方法
List<SysRole> roleList = userRoleMapper.selectSysRolesByUserIdAndRoleEnable2(sysUser, sysRole);
// 期望roleList不為空
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 ");
}
}
日誌
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, 管理員, 1, 1, 2018-04-13 21:12:46.0
2018-04-16 20:13:07,487 TRACE [main] (BaseJdbcLogger.java:148) - <== Row: 2, 普通使用者, 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=管理員, 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=普通使用者, 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
小結
除了上述常用的型別，介面的引數還可以是集合或者陣列，後續介紹。