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import org.apache.ibatis.executor.Executor;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.plugin.*;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Map;
import java.util.Properties;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.locks.ReentrantLock;
/**
* Mybatis - 通用分页拦截器
*
*/
@SuppressWarnings("rawtypes")
@Intercepts(@Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class}))
public class PageHelper implements Interceptor {
//sql工具类
private SqlUtil sqlUtil;
//属性参数信息
private Properties properties;
//配置对象方式
private SqlUtilConfig sqlUtilConfig;
//自动获取dialect,如果没有setProperties或setSqlUtilConfig，也可以正常进行
private boolean autoDialect = true;
//运行时自动获取dialect
private boolean autoRuntimeDialect;
//多数据源时，获取jdbcurl后是否关闭数据源
private boolean closeConn = true;
//缓存
private Map<String, SqlUtil> urlSqlUtilMap = new ConcurrentHashMap<String, SqlUtil>();
private ReentrantLock lock = new ReentrantLock();
/**
* 获取任意查询方法的count总数
*
* @param select
* @return
*/
public static long count(ISelect select) {
Page<?> page = startPage(1, -1, true);
select.doSelect();
return page.getTotal();
}
/**
* 开始分页
*
* @param pageNum 页码
* @param pageSize 每页显示数量
*/
public static <E> Page<E> startPage(int pageNum, int pageSize) {
return startPage(pageNum, pageSize, true);
}
/**
* 开始分页
*
* @param pageNum 页码
* @param pageSize 每页显示数量
* @param count 是否进行count查询
*/
public static <E> Page<E> startPage(int pageNum, int pageSize, boolean count) {
return startPage(pageNum, pageSize, count, null);
}
/**
* 开始分页
*
* @param pageNum 页码
* @param pageSize 每页显示数量
* @param orderBy 排序
*/
public static <E> Page<E> startPage(int pageNum, int pageSize, String orderBy) {
Page<E> page = startPage(pageNum, pageSize);
page.setOrderBy(orderBy);
return page;
}
/**
* 开始分页
*
* @param offset 页码
* @param limit 每页显示数量
*/
public static <E> Page<E> offsetPage(int offset, int limit) {
return offsetPage(offset, limit, true);
}
/**
* 开始分页
*
* @param offset 页码
* @param limit 每页显示数量
* @param count 是否进行count查询
*/
public static <E> Page<E> offsetPage(int offset, int limit, boolean count) {
Page<E> page = new Page<E>(new int[]{offset, limit}, count);
//当已经执行过orderBy的时候
Page<E> oldPage = SqlUtil.getLocalPage();
if (oldPage != null && oldPage.isOrderByOnly()) {
page.setOrderBy(oldPage.getOrderBy());
}
SqlUtil.setLocalPage(page);
return page;
}
/**
* 开始分页
*
* @param offset 页码
* @param limit 每页显示数量
* @param orderBy 排序
*/
public static <E> Page<E> offsetPage(int offset, int limit, String orderBy) {
Page<E> page = offsetPage(offset, limit);
page.setOrderBy(orderBy);
return page;
}
/**
* 开始分页
*
* @param pageNum 页码
* @param pageSize 每页显示数量
* @param count 是否进行count查询
* @param reasonable 分页合理化,null时用默认配置
*/
public static <E> Page<E> startPage(int pageNum, int pageSize, boolean count, Boolean reasonable) {
return startPage(pageNum, pageSize, count, reasonable, null);
}
/**
* 开始分页
*
* @param pageNum 页码
* @param pageSize 每页显示数量
* @param count 是否进行count查询
* @param reasonable 分页合理化,null时用默认配置
* @param pageSizeZero true且pageSize=0时返回全部结果，false时分页,null时用默认配置
*/
public static <E> Page<E> startPage(int pageNum, int pageSize, boolean count, Boolean reasonable, Boolean pageSizeZero) {
Page<E> page = new Page<E>(pageNum, pageSize, count);
page.setReasonable(reasonable);
page.setPageSizeZero(pageSizeZero);
//当已经执行过orderBy的时候
Page<E> oldPage = SqlUtil.getLocalPage();
if (oldPage != null && oldPage.isOrderByOnly()) {
page.setOrderBy(oldPage.getOrderBy());
}
SqlUtil.setLocalPage(page);
return page;
}
/**
* 开始分页
*
* @param params
*/
public static <E> Page<E> startPage(Object params) {
Page<E> page = SqlUtil.getPageFromObject(params);
//当已经执行过orderBy的时候
Page<E> oldPage = SqlUtil.getLocalPage();
if (oldPage != null && oldPage.isOrderByOnly()) {
page.setOrderBy(oldPage.getOrderBy());
}
SqlUtil.setLocalPage(page);
return page;
}
/**
* 排序
*
* @param orderBy
*/
public static void orderBy(String orderBy) {
Page<?> page = SqlUtil.getLocalPage();
if (page != null) {
page.setOrderBy(orderBy);
} else {
page = new Page();
page.setOrderBy(orderBy);
page.setOrderByOnly(true);
SqlUtil.setLocalPage(page);
}
}
/**
* 获取orderBy
*
* @return
*/
public static String getOrderBy() {
Page<?> page = SqlUtil.getLocalPage();
if (page != null) {
String orderBy = page.getOrderBy();
if (StringUtil.isEmpty(orderBy)) {
return null;
} else {
return orderBy;
}
}
return null;
}
/**
* Mybatis拦截器方法
*
* @param invocation 拦截器入参
* @return 返回执行结果
* @throws Throwable 抛出异常
*/
public Object intercept(Invocation invocation) throws Throwable {
if (autoRuntimeDialect) {
SqlUtil sqlUtil = getSqlUtil(invocation);
return sqlUtil.processPage(invocation);
} else {
if (autoDialect) {
initSqlUtil(invocation);
}
return sqlUtil.processPage(invocation);
}
}
/**
* 初始化sqlUtil
*
* @param invocation
*/
public synchronized void initSqlUtil(Invocation invocation) {
if (this.sqlUtil == null) {
this.sqlUtil = getSqlUtil(invocation);
if (!autoRuntimeDialect) {
properties = null;
sqlUtilConfig = null;
}
autoDialect = false;
}
}
/**
* 获取url
*
* @param dataSource
* @return
*/
public String getUrl(DataSource dataSource){
Connection conn = null;
try {
conn = dataSource.getConnection();
return conn.getMetaData().getURL();
} catch (SQLException e) {
throw new RuntimeException(e);
} finally {
if(conn != null){
try {
if(closeConn){
conn.close();
}
} catch (SQLException e) {
//ignore
}
}
}
}
/**
* 根据datasource创建对应的sqlUtil
*
* @param invocation
*/
public SqlUtil getSqlUtil(Invocation invocation) {
MappedStatement ms = (MappedStatement) invocation.getArgs()[0];
//改为对dataSource做缓存
DataSource dataSource = ms.getConfiguration().getEnvironment().getDataSource();
String url = getUrl(dataSource);
if (urlSqlUtilMap.containsKey(url)) {
return urlSqlUtilMap.get(url);
}
try {
lock.lock();
if (urlSqlUtilMap.containsKey(url)) {
return urlSqlUtilMap.get(url);
}
if (StringUtil.isEmpty(url)) {
throw new RuntimeException("无法自动获取jdbcUrl，请在分页插件中配置dialect参数!");
}
String dialect = Dialect.fromJdbcUrl(url);
if (dialect == null) {
throw new RuntimeException("无法自动获取数据库类型，请通过dialect参数指定!");
}
SqlUtil sqlUtil = null;
if (properties != null) {
sqlUtil = new SqlUtil(dialect, properties.getProperty("sqlCacheClass"));
sqlUtil.setProperties(properties);
} else if (sqlUtilConfig != null) {
sqlUtil = new SqlUtil(dialect, sqlUtilConfig.getSqlCacheClass());
sqlUtil.setSqlUtilConfig(sqlUtilConfig);
}
urlSqlUtilMap.put(url, sqlUtil);
return sqlUtil;
} finally {
lock.unlock();
}
}
/**
* 只拦截Executor
*
* @param target
* @return
*/
public Object plugin(Object target) {
if (target instanceof Executor) {
return Plugin.wrap(target, this);
} else {
return target;
}
}
private void checkVersion() {
//MyBatis3.2.0版本校验
try {
Class.forName("org.apache.ibatis.scripting.xmltags.SqlNode");//SqlNode是3.2.0之后新增的类
} catch (ClassNotFoundException e) {
throw new RuntimeException("您使用的MyBatis版本太低，MyBatis分页插件PageHelper支持MyBatis3.2.0及以上版本!");
}
}
/**
* 设置属性值
*
* @param p 属性值
*/
public void setProperties(Properties p) {
checkVersion();
//多数据源时，获取jdbcurl后是否关闭数据源
String closeConn = p.getProperty("closeConn");
//解决#97
if(StringUtil.isNotEmpty(closeConn)){
this.closeConn = Boolean.parseBoolean(closeConn);
}
//初始化SqlUtil的PARAMS
SqlUtil.setParams(p.getProperty("params"));
//数据库方言
String dialect = p.getProperty("dialect");
String runtimeDialect = p.getProperty("autoRuntimeDialect");
if (StringUtil.isNotEmpty(runtimeDialect) && runtimeDialect.equalsIgnoreCase("TRUE")) {
this.autoRuntimeDialect = true;
this.autoDialect = false;
this.properties = p;
} else if (StringUtil.isEmpty(dialect)) {
autoDialect = true;
this.properties = p;
} else {
autoDialect = false;
sqlUtil = new SqlUtil(dialect, p.getProperty("sqlCacheClass"));
sqlUtil.setProperties(p);
}
}
/**
* 设置属性值
*
* @param config
*/
public void setSqlUtilConfig(SqlUtilConfig config) {
checkVersion();
//初始化SqlUtil的PARAMS
SqlUtil.setParams(config.getParams());
//多数据源时，获取jdbcurl后是否关闭数据源
this.closeConn = config.isCloseConn();
if (config.isAutoRuntimeDialect()) {
this.autoRuntimeDialect = true;
this.autoDialect = false;
this.sqlUtilConfig = config;
} else if (StringUtil.isEmpty(config.getDialect())) {
autoDialect = true;
this.sqlUtilConfig = config;
} else {
autoDialect = false;
sqlUtil = new SqlUtil(config.getDialect(), config.getSqlCacheClass());
sqlUtil.setSqlUtilConfig(config);
}
}
}
