Mybatis实现数据库分页查询

Mybatis提供一个RowBounds类型，在查询指定RowBounds参数对象可以控制查询记录的起点和数量。

此案例在之前代码基础上执行：

http://blog.csdn.net/u013821825/article/details/51620371

1、SqlMapConfig.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//ibatis.apache.org//DTD Config 3.0//EN"
"http://ibatis.apache.org/dtd/ibatis-3-config.dtd">
<configuration>
<environments default="environment">
<environment id="environment">
<transactionManager type="JDBC" />
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver" />
<property name="url" value="jdbc:mysql://localhost:3306/test" />
<property name="username" value="root" />
<property name="password" value="root" />
</dataSource>
</environment>
</environments>

<mappers>
<mapper resource="org/xsx/entity/EmpSQL.xml" />
</mappers>
</configuration>

2、实体类和其映射接口

package org.xsx.entity;

public class Emp {
private Integer id;
private String name;
private Integer age;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}

}

package org.xsx.entity;

import java.util.List;

public interface EmpMapper{

public void addEmp(Emp emp);

public void updateEmp(Emp emp);

public Emp findById(int id);

public void deleteById(int id);

public List<Emp> findAll();
}

3、EmpSQL.xml配置wenjian

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//ibatis.apache.org//DTD Mapper 3.0//EN"
"http://ibatis.apache.org/dtd/ibatis-3-mapper.dtd">
<mapper namespace="org.xsx.entity.EmpMapper">

<insert id="addEmp"
parameterType="org.xsx.entity.Emp">
insert into emp (id,name,age)
values (#{id},#{name},#{age})
</insert>

<update id="updateEmp" parameterType="org.xsx.entity.Emp">
update emp set name=#{name},age=#{age} where id=#{id}
</update>

<select id="findById" parameterType="int" resultType="org.xsx.entity.Emp">
select name,age from emp where id=#{id}
</select>

<delete id="deleteById" parameterType="int">
delete from emp where id=#{id}
</delete>

<select id="findAll" resultType="org.xsx.entity.Emp">
select id,name,age from emp
</select>
</mapper>

4、测试方法

package org.xsx.test;

import java.io.IOException;
import java.io.Reader;
import java.util.List;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.RowBounds;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;
import org.xsx.entity.Emp;

public class TestEmp extends MybatisHelper {

static{
conf =  "SqlMapConfig.xml";
}

@Test
public void testDatasource() throws Exception{
String conf = "SqlMapConfig.xml";
Reader reader = Resources.getResourceAsReader(conf);
//SessionFactoryBuilder对象
SqlSessionFactoryBuilder builder  = new SqlSessionFactoryBuilder();
SqlSessionFactory factory = builder.build(reader);

//Session
SqlSession session = factory.openSession();

System.out.println(session);
session.close();
}

@Test
public void testAddEmp() throws Exception{
//      String conf = "SqlMapConfig.xml";
//      Reader reader = Resources.getResourceAsReader(conf);
//      //SessionFactoryBuilder对象
//      SqlSessionFactoryBuilder builder  = new SqlSessionFactoryBuilder();
//      SqlSessionFactory factory = builder.build(reader);

//Session
SqlSession session = factory.openSession();

Emp emp = new Emp();
emp.setId(4);
emp.setName("da");
emp.setAge(91);

session.insert("addEmp", emp);
session.commit();
session.close();
}

@Test
public void testUpdate(){
//Session
SqlSession session = factory.openSession();

Emp emp = (Emp)session.selectOne("findById", 3);
emp.setId(3);
emp.setName("ccc");
emp.setAge(100);

session.update("updateEmp", emp);
session.commit();
session.close();
}

@Test
public void testFindById(){
//Session
SqlSession session = factory.openSession();

Emp emp = (Emp)session.selectOne("findById", 3);
System.out.println(emp.getName());
session.close();
}

@Test
public void testDeleteById(){
//Session
SqlSession session = factory.openSession();

session.delete("deleteById", 4);
session.commit();
session.close();
}

@Test
public void testRowBounds(){
//Session
SqlSession session = factory.openSession();

int offset = 0;//起点
int limit=3;//数量

RowBounds rowBounds = new RowBounds(offset, limit);
List<Emp> list = session.selectList("findAll", null, rowBounds);

for(Emp e:list){
System.out.println(e.getId()+"--"+e.getName()+"--"+e.getAge());
}

session.close();
}
}

5、静态加载类准备SqlSession资源

package org.xsx.test;

import java.io.Reader;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Before;

public class MybatisHelper {
public static String conf ;
public static Reader reader;
public static SqlSessionFactoryBuilder builder;
public static SqlSessionFactory factory;

@Before
public void startMybatis() throws Exception{
reader = Resources.getResourceAsReader(conf);
builder = new SqlSessionFactoryBuilder();
factory = builder.build(reader);
}
}

6、结果