MyBatis 的 MySQL、Oracle 分页插件，使用相同的分页接口。
/**
* 分页对象.
*
* @author <a href="mailto:DL88250@gmail.com">Liang Ding</a>
* @version 1.0.1.0, Oct 6, 2012
*/
public final class Page implements Serializable {
/**
* 默认的序列化版本 id.
*/
private static final long serialVersionUID = 1L;
/**
* 分页查询开始记录位置.
*/
private int begin;
/**
* 分页查看下结束位置.
*/
private int end;
/**
* 每页显示记录数.
*/
private int length = 20;
/**
* 查询结果总记录数.
*/
private int totalRecords;
/**
* 当前页码.
*/
private int pageNo;
/**
* 总共页数.
*/
private int pageCount;
public Page() {
}
/**
* 构造函数.
*
* @param begin
* @param length
*/
public Page(int begin, int length) {
this.begin = begin;
this.length = length;
this.end = this.begin + this.length;
this.pageNo = (int) Math.floor((this.begin * 1.0d) / this.length) + 1;
}
/**
* @param begin
* @param length
* @param count
*/
public Page(int begin, int length, int totalRecords) {
this(begin, length);
this.totalRecords = totalRecords;
}
/**
* 设置页数，自动计算数据范围.
*
* @param pageNo
*/
public Page(int pageNo) {
this.pageNo = pageNo;
pageNo = pageNo > 0 ? pageNo : 1;
this.begin = this.length * (pageNo - 1);
this.end = this.length * pageNo;
}
/**
* @return the begin
*/
public int getBegin() {
return begin;
}
/**
* @return the end
*/
public int getEnd() {
return end;
}
/**
* @param end
* the end to set
*/
public void setEnd(int end) {
this.end = end;
}
/**
* @param begin
* the begin to set
*/
public void setBegin(int begin) {
this.begin = begin;
if (this.length != 0) {
this.pageNo = (int) Math.floor((this.begin * 1.0d) / this.length) + 1;
}
}
/**
* @return the length
*/
public int getLength() {
return length;
}
/**
* @param length
* the length to set
*/
public void setLength(int length) {
this.length = length;
if (this.begin != 0) {
this.pageNo = (int) Math.floor((this.begin * 1.0d) / this.length) + 1;
}
}
/**
* @return the totalRecords
*/
public int getTotalRecords() {
return totalRecords;
}
/**
* @param totalRecords
* the totalRecords to set
*/
public void setTotalRecords(int totalRecords) {
this.totalRecords = totalRecords;
this.pageCount = (int) Math.floor((this.totalRecords * 1.0d) / this.length);
if (this.totalRecords % this.length != 0) {
this.pageCount++;
}
}
/**
* @return the pageNo
*/
public int getPageNo() {
return pageNo;
}
/**
* @param pageNo
* the pageNo to set
*/
public void setPageNo(int pageNo) {
this.pageNo = pageNo;
pageNo = pageNo > 0 ? pageNo : 1;
this.begin = this.length * (pageNo - 1);
this.end = this.length * pageNo;
}
/**
* @return the pageCount
*/
public int getPageCount() {
if (pageCount == 0) {
return 1;
}
return pageCount;
}
/**
* @param pageCount
* the pageCount to set
*/
public void setPageCount(int pageCount) {
this.pageCount = pageCount;
}
@Override
public String toString() {
final StringBuilder builder = new StringBuilder("begin=").append(begin).append(", end=")
.append(end).append(", length=").append(length).append(", totalRecords=").append(
totalRecords).append(", pageNo=").append(pageNo).append(", pageCount=")
.append(pageCount);
return builder.toString();
}
}
/**
* Oracle 分页生成插件。
*
* @author <a href="mailto:DL88250@gmail.com">Liang Ding</a>
* @version 1.0.0.0, May 31, 2012
*/
public class OraclePaginationPlugin extends PluginAdapter {
@Override
public boolean modelExampleClassGenerated(TopLevelClass topLevelClass,
IntrospectedTable introspectedTable) {
// add field, getter, setter for limit clause
addPage(topLevelClass, introspectedTable, "page");
return super.modelExampleClassGenerated(topLevelClass, introspectedTable);
}
@Override
public boolean sqlMapDocumentGenerated(Document document, IntrospectedTable introspectedTable) {
XmlElement parentElement = document.getRootElement();
// 产生分页语句前半部分
XmlElement paginationPrefixElement = new XmlElement("sql");
paginationPrefixElement.addAttribute(new Attribute("id", "OracleDialectPrefix"));
XmlElement pageStart = new XmlElement("if");
pageStart.addAttribute(new Attribute("test", "page != null"));
pageStart.addElement(new TextElement(
"select * from ( select row_.*, rownum rownum_ from ( "));
paginationPrefixElement.addElement(pageStart);
parentElement.addElement(paginationPrefixElement);
// 产生分页语句后半部分
XmlElement paginationSuffixElement = new XmlElement("sql");
paginationSuffixElement.addAttribute(new Attribute("id", "OracleDialectSuffix"));
XmlElement pageEnd = new XmlElement("if");
pageEnd.addAttribute(new Attribute("test", "page != null"));
pageEnd
.addElement(new TextElement(
"<![CDATA[ ) row_ where rownum <= #{page.end} ) where rownum_ > #{page.begin} ]]>"));
paginationSuffixElement.addElement(pageEnd);
parentElement.addElement(paginationSuffixElement);
return super.sqlMapDocumentGenerated(document, introspectedTable);
}
@Override
public boolean sqlMapSelectByExampleWithoutBLOBsElementGenerated(XmlElement element,
IntrospectedTable introspectedTable) {
XmlElement pageStart = new XmlElement("include"); //$NON-NLS-1$
pageStart.addAttribute(new Attribute("refid", "OracleDialectPrefix"));
element.getElements().add(0, pageStart);
XmlElement isNotNullElement = new XmlElement("include"); //$NON-NLS-1$
isNotNullElement.addAttribute(new Attribute("refid", "OracleDialectSuffix"));
element.getElements().add(isNotNullElement);
return super.sqlMapUpdateByExampleWithoutBLOBsElementGenerated(element, introspectedTable);
}
/**
* @param topLevelClass
* @param introspectedTable
* @param name
*/
private void addPage(TopLevelClass topLevelClass, IntrospectedTable introspectedTable,
String name) {
topLevelClass.addImportedType(new FullyQualifiedJavaType(
"com.yuanxin.framework.mybatis.Page"));
CommentGenerator commentGenerator = context.getCommentGenerator();
Field field = new Field();
field.setVisibility(JavaVisibility.PROTECTED);
field.setType(new FullyQualifiedJavaType("com.yuanxin.framework.mybatis.Page"));
field.setName(name);
commentGenerator.addFieldComment(field, introspectedTable);
topLevelClass.addField(field);
char c = name.charAt(0);
String camel = Character.toUpperCase(c) + name.substring(1);
Method method = new Method();
method.setVisibility(JavaVisibility.PUBLIC);
method.setName("set" + camel);
method.addParameter(new Parameter(new FullyQualifiedJavaType(
"com.yuanxin.framework.mybatis.Page"), name));
method.addBodyLine("this." + name + "=" + name + ";");
commentGenerator.addGeneralMethodComment(method, introspectedTable);
topLevelClass.addMethod(method);
method = new Method();
method.setVisibility(JavaVisibility.PUBLIC);
method.setReturnType(new FullyQualifiedJavaType("com.yuanxin.framework.mybatis.Page"));
method.setName("get" + camel);
method.addBodyLine("return " + name + ";");
commentGenerator.addGeneralMethodComment(method, introspectedTable);
topLevelClass.addMethod(method);
}
/**
* This plugin is always valid - no properties are required
*/
@Override
public boolean validate(List<String> warnings) {
return true;
}
}
/**
* MySQL 分页生成插件。
*
* @author <a href="mailto:DL88250@gmail.com">Liang Ding</a>
* @version 1.0.0.1, Oct 10, 2012
*/
public final class MySQLPaginationPlugin extends PluginAdapter {
@Override
public boolean modelExampleClassGenerated(TopLevelClass topLevelClass,
IntrospectedTable introspectedTable) {
// add field, getter, setter for limit clause
addPage(topLevelClass, introspectedTable, "page");
return super.modelExampleClassGenerated(topLevelClass, introspectedTable);
}
@Override
public boolean sqlMapSelectByExampleWithoutBLOBsElementGenerated(XmlElement element,
IntrospectedTable introspectedTable) {
XmlElement page = new XmlElement("if");
page.addAttribute(new Attribute("test", "page != null"));
page.addElement(new TextElement("limit #{page.begin} , #{page.length}"));
element.addElement(page);
return super.sqlMapUpdateByExampleWithoutBLOBsElementGenerated(element, introspectedTable);
}
/**
* @param topLevelClass
* @param introspectedTable
* @param name
*/
private void addPage(TopLevelClass topLevelClass, IntrospectedTable introspectedTable,
String name) {
topLevelClass.addImportedType(new FullyQualifiedJavaType(
"com.yuanxin.framework.mybatis.Page"));
CommentGenerator commentGenerator = context.getCommentGenerator();
Field field = new Field();
field.setVisibility(JavaVisibility.PROTECTED);
field.setType(new FullyQualifiedJavaType("com.yuanxin.framework.mybatis.Page"));
field.setName(name);
commentGenerator.addFieldComment(field, introspectedTable);
topLevelClass.addField(field);
char c = name.charAt(0);
String camel = Character.toUpperCase(c) + name.substring(1);
Method method = new Method();
method.setVisibility(JavaVisibility.PUBLIC);
method.setName("set" + camel);
method.addParameter(new Parameter(new FullyQualifiedJavaType(
"com.yuanxin.framework.mybatis.Page"), name));
method.addBodyLine("this." + name + "=" + name + ";");
commentGenerator.addGeneralMethodComment(method, introspectedTable);
topLevelClass.addMethod(method);
method = new Method();
method.setVisibility(JavaVisibility.PUBLIC);
method.setReturnType(new FullyQualifiedJavaType("com.yuanxin.framework.mybatis.Page"));
method.setName("get" + camel);
method.addBodyLine("return " + name + ";");
commentGenerator.addGeneralMethodComment(method, introspectedTable);
topLevelClass.addMethod(method);
}
/**
* This plugin is always valid - no properties are required
*/
public boolean validate(List<String> warnings) {
return true;
}
}
使用时在 generatorConfig.xml 中配置对应的插件即可，最终，在生成的 Criteria 中就会存在 Page 字段，用于设置分页。
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