MyBatis3.1.1+Spring3.1.1的增、删、查、改以及分页和事务管理
1. [代码]Mybatis全局配置文件
<
plugins
>
<
plugin
interceptor
=
"com.has.core.page.PaginationInterceptor"
/>
</
plugins
>
2. [文件] PaginationInterceptor.java
@Intercepts
({
@Signature
(type = StatementHandler.
class
, method =
"prepare"
, args = { Connection.
class
}) })
public
class
PaginationInterceptor
implements
Interceptor {
@Override
public
Object intercept(Invocation invocation)
throws
Throwable {
StatementHandler statementHandler = (StatementHandler) invocation.getTarget();
BoundSql boundSql = statementHandler.getBoundSql();
MetaObject metaStatementHandler = MetaObject.forObject(statementHandler);
RowBounds rowBounds = (RowBounds) metaStatementHandler.getValue(
"delegate.rowBounds"
);
if
(rowBounds ==
null
|| rowBounds == RowBounds.DEFAULT) {
return
invocation.proceed();
}
Configuration configuration = (Configuration) metaStatementHandler.getValue(
"delegate.configuration"
);
Dialect.Type databaseType =
null
;
try
{
databaseType = Dialect.Type.valueOf(configuration.getVariables().getProperty(
"dialect"
).toUpperCase());
}
catch
(Exception e) {
}
if
(databaseType ==
null
) {
throw
new
RuntimeException(
"the value of the dialect property in configuration.xml is not defined : "
+ configuration.getVariables().getProperty(
"dialect"
));
}
Dialect dialect =
null
;
switch
(databaseType) {
case
MYSQL:
dialect =
new
MySql5Dialect();
break
;
case
ORACLE:
dialect =
new
OracleDialect();
break
;
}
String originalSql = (String) metaStatementHandler.getValue(
"delegate.boundSql.sql"
);
metaStatementHandler.setValue(
"delegate.boundSql.sql"
,
dialect.getLimitString(originalSql, rowBounds.getOffset(), rowBounds.getLimit()));
metaStatementHandler.setValue(
"delegate.rowBounds.offset"
, RowBounds.NO_ROW_OFFSET);
metaStatementHandler.setValue(
"delegate.rowBounds.limit"
, RowBounds.NO_ROW_LIMIT);
return
invocation.proceed();
}
@Override
public
Object plugin(Object target) {
return
Plugin.wrap(target,
this
);
}
@Override
public
void
setProperties(Properties properties) {
}
}
3. [文件] Dialect.java
/**
* 数据库方言定义
*
*/
public
abstract
class
Dialect {
public
static
enum
Type {
MYSQL, ORACLE
}
public
abstract
String getLimitString(String sql,
int
skipResults,
int
maxResults);
}
4. [文件] MySql5Dialect.java
/**
* mysql方言分页类
*/
public
class
MySql5Dialect
extends
Dialect {
protected
static
final
String SQL_END_DELIMITER =
";"
;
public
String getLimitString(String sql,
boolean
hasOffset) {
return
MySql5PageHepler.getLimitString(sql, -
1
, -
1
);
}
public
String getLimitString(String sql,
int
offset,
int
limit) {
return
MySql5PageHepler.getLimitString(sql, offset, limit);
}
public
boolean
supportsLimit() {
return
true
;
}
}
5. [文件] OracleDialect.java
package com.chyjr.has.core.page.dialect;
/**
* oracel方言分页
*
*/
public class OracleDialect extends Dialect {
public String getLimitString(String sql, int offset, int limit) {
// TODO 未实现
return "";
}
}
6. [文件] MySql5PageHepler.java
import
java.util.regex.Matcher;
import
java.util.regex.Pattern;
/**
* mysql分页工具类
*/
public
class
MySql5PageHepler {
/**
* 得到查询总数的sql
*/
public
static
String getCountString(String querySelect) {
querySelect = getLineSql(querySelect);
int
orderIndex = getLastOrderInsertPoint(querySelect);
int
formIndex = getAfterFormInsertPoint(querySelect);
String select = querySelect.substring(
0
, formIndex);
// 如果SELECT 中包含 DISTINCT 只能在外层包含COUNT
if
(select.toLowerCase().indexOf(
"select distinct"
) != -
1
|| querySelect.toLowerCase().indexOf(
"group by"
) != -
1
) {
return
new
StringBuffer(querySelect.length()).append(
"select count(1) count from ("
)
.append(querySelect.substring(
0
, orderIndex)).append(
" ) t"
).toString();
}
else
{
return
new
StringBuffer(querySelect.length()).append(
"select count(1) count "
)
.append(querySelect.substring(formIndex, orderIndex)).toString();
}
}
/**
* 得到最后一个Order By的插入点位置
*
* @return 返回最后一个Order By插入点的位置
*/
private
static
int
getLastOrderInsertPoint(String querySelect) {
int
orderIndex = querySelect.toLowerCase().lastIndexOf(
"order by"
);
if
(orderIndex == -
1
|| !isBracketCanPartnership(querySelect.substring(orderIndex, querySelect.length()))) {
throw
new
RuntimeException(
"My SQL 分页必须要有Order by 语句!"
);
}
return
orderIndex;
}
/**
* 得到分页的SQL
*
* @param offset
* 偏移量
* @param limit
* 位置
* @return 分页SQL
*/
public
static
String getLimitString(String querySelect,
int
offset,
int
limit) {
querySelect = getLineSql(querySelect);
// String sql = querySelect.replaceAll("[^\\s,]+\\.", "") + " limit " +
// offset + " ," + limit;
String sql = querySelect +
" limit "
+ offset +
" ,"
+ limit;
return
sql;
}
/**
* 将SQL语句变成一条语句,并且每个单词的间隔都是1个空格
*
* @param sql
* SQL语句
* @return 如果sql是NULL返回空,否则返回转化后的SQL
*/
private
static
String getLineSql(String sql) {
return
sql.replaceAll(
"[\r\n]"
,
" "
).replaceAll(
"\\s{2,}"
,
" "
);
}
/**
* 得到SQL第一个正确的FROM的的插入点
*/
private
static
int
getAfterFormInsertPoint(String querySelect) {
String regex =
"\\s+FROM\\s+"
;
Pattern pattern = Pattern.compile(regex, Pattern.CASE_INSENSITIVE);
Matcher matcher = pattern.matcher(querySelect);
while
(matcher.find()) {
int
fromStartIndex = matcher.start(
0
);
String text = querySelect.substring(
0
, fromStartIndex);
if
(isBracketCanPartnership(text)) {
return
fromStartIndex;
}
}
return
0
;
}
/**
* 判断括号"()"是否匹配,并不会判断排列顺序是否正确
*
* @param text
* 要判断的文本
* @return 如果匹配返回TRUE,否则返回FALSE
*/
private
static
boolean
isBracketCanPartnership(String text) {
if
(text ==
null
|| (getIndexOfCount(text,
'('
) != getIndexOfCount(text,
')'
))) {
return
false
;
}
return
true
;
}
/**
* 得到一个字符在另一个字符串中出现的次数
*
* @param text
* 文本
* @param ch
* 字符
*/
private
static
int
getIndexOfCount(String text,
char
ch) {
int
count =
0
;
for
(
int
i =
0
; i < text.length(); i++) {
count = (text.charAt(i) == ch) ? count +
1
: count;
}
return
count;
}
}
2. [图片] Mybatis.jpg
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