Mybatis（九）分页插件PageHelper使用

一． Mybatis分页插件PageHelper使用

 1、不使用插件如何分页：

使用mybatis实现：

1)接口：

List<Student> selectStudent(Map<String, Object> map);

2）mapper.xml:

<select id="selectStudent" resultMap="BaseResultMap" parameterType="java.util.Map" >
    select 
    <include refid="Base_Column_List" />
    from student  limit #{pageNum},#{pageSize}
  </select>

3）测试：

@Test
    public void TestGetStudent() throws IOException {
        try {        
            StudentMapper mapper=session.getMapper(StudentMapper.class);
            Map<String,Object> map=new HashMap<String,Object>();
            map.put("pageNum", 0);
            map.put("pageSize", 3);
            List<Student> students=mapper.selectStudent(map);
            
            for(Student student :students)
                System.out.println(student.gettId() + "   " + student.gettName() + "  "+student.gettAge()+" "+student.gettEnterdate()+"  "+student.gettSid());

        }finally {
            session.close();
    }
        
    }

2 使用PageHelper插件如何分页：

下载地址：

https://github.com/pagehelper/Mybatis-PageHelper

https://github.com/JSQLParser/JSqlParser

另外一个地址：

Pagehelper下载地址：

http://repo1.maven.org/maven2/com/github/pagehelper/pagehelper/

jsqlparser 下载地址：

http://repo1.maven.org/maven2/com/github/jsqlparser/jsqlparser/

使用步骤：

1、导入相关包pagehelper-x.x.x.jar 和  jsqlparser-x.x.x.jar。

2、在MyBatis全局配置文件中配置分页插件。

   <plugins>

<plugin interceptor="com.github.pagehelper.PageInterceptor"></plugin>

</plugins>

3、使用PageHelper提供的方法进行分页

  StudentMapper mapper = session.getMapper(StudentMapper.class);
//放在查询之前            
Page<Object> page = PageHelper.startPage(1, 3);
                
    StudentExample example=null;
    List<Student> students=mapper.selectByExample(example);

    for(Student student :students)
        System.out.println(student.gettId() + "   " + student.gettName() + "  "+student.gettAge()+" "+student.gettEnterdate()+"  "+student.gettSid());
    System.out.println("当前页码："+page.getPageNum());
    System.out.println("总记录数："+page.getTotal());
    System.out.println("每页的记录数："+page.getPageSize());
    System.out.println("总页码："+page.getPages());

4、可以使用更强大的PageInfo封装返回结果

           StudentMapper mapper = session.getMapper(StudentMapper.class);
            Page<Object> page = PageHelper.startPage(1, 3);
                
            StudentExample example=null;
            List<Student> students=mapper.selectByExample(example);                
                for(Student student :students)
                    System.out.println(student.gettId() + "   " + student.gettName() + "  "+student.gettAge()+" "+student.gettEnterdate()+"  "+student.gettSid());                
                 PageInfo<Student> info = new PageInfo<Student>(students, 3);                    
                    System.out.println("当前页码："+info.getPageNum());
                    System.out.println("总记录数："+info.getTotal());
                    System.out.println("每页的记录数："+info.getPageSize());
                    System.out.println("总页码："+info.getPages());
                    System.out.println("是否第一页："+info.isIsFirstPage());
                    System.out.println("连续显示的页码：");
                    int[] nums = info.getNavigatepageNums();
                    for (int i = 0; i < nums.length; i++) {
                        System.out.println(nums[i]);
                    }