Spring使用JdbcTemplate实现对数据库操作
Spring使用JdbcTemplate实现对数据库操作
zhangxin900607 发表于1年前
Spring使用JdbcTemplate实现对数据库操作
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转载于:http://www.16boke.com/article/detail/15


Spring对数据库的操作使用JdbcTemplate来封装JDBC,结合Spring的注入特性可以很方便的实现对数据库的访问操作。

使用JdbcTemplate可以像JDBC一样来编写数据库的操作代码,与hibernate相比对SQL语句的控制上会更灵活,下面以一个例子来讲解JdbcTemplate的使用及相应的API。


一、实体Bean

package com.orm.dto;

import java.sql.Timestamp;

public class AreaDto implements java.io.Serializable {

	private static final long serialVersionUID = 1L;
	private Integer areaid;
	private String area_name;
	private String area_detail;
	private Integer floor_id;
	private Integer build_id;
	private String region_name;
	private String sortno;
	private Timestamp insert_time;
	private Timestamp update_time;
	private Integer operate_id;

	public AreaDto() {
	}

	public AreaDto(Integer areaid) {
		this.areaid = areaid;
	}

	public Integer getAreaid() {
		return areaid;
	}

	public void setAreaid(Integer areaid) {
		this.areaid = areaid;
	}

	public String getArea_name() {
		return area_name;
	}

	public void setArea_name(String area_name) {
		this.area_name = area_name;
	}

	public String getArea_detail() {
		return area_detail;
	}

	public void setArea_detail(String area_detail) {
		this.area_detail = area_detail;
	}

	public Integer getFloor_id() {
		return floor_id;
	}

	public void setFloor_id(Integer floor_id) {
		this.floor_id = floor_id;
	}

	public Integer getBuild_id() {
		return build_id;
	}

	public void setBuild_id(Integer build_id) {
		this.build_id = build_id;
	}

	public String getRegion_name() {
		return region_name;
	}

	public void setRegion_name(String region_name) {
		this.region_name = region_name;
	}

	public String getSortno() {
		return sortno;
	}

	public void setSortno(String sortno) {
		this.sortno = sortno;
	}

	public Timestamp getInsert_time() {
		return insert_time;
	}

	public void setInsert_time(Timestamp insert_time) {
		this.insert_time = insert_time;
	}

	public Timestamp getUpdate_time() {
		return update_time;
	}

	public void setUpdate_time(Timestamp update_time) {
		this.update_time = update_time;
	}

	public Integer getOperate_id() {
		return operate_id;
	}

	public void setOperate_id(Integer operate_id) {
		this.operate_id = operate_id;
	}

}

package com.orm.dto;

import java.sql.Timestamp;

public class BuildingDto implements java.io.Serializable {

	private static final long serialVersionUID = 1L;
	private Integer buildid;
	private String buildname;
	private String detail;
	private String sortno;
	private Timestamp insertTime;
	private Timestamp updateTime;
	private Integer operateId;

	public BuildingDto() {
	}

	public BuildingDto(Integer buildid) {
		this.buildid = buildid;
	}

	public BuildingDto(Integer buildid, String buildname, String detail, String sortno, Timestamp insertTime,
			Timestamp updateTime, Integer operateId) {
		this.buildid = buildid;
		this.buildname = buildname;
		this.detail = detail;
		this.sortno = sortno;
		this.insertTime = insertTime;
		this.updateTime = updateTime;
		this.operateId = operateId;
	}

	public Integer getBuildid() {
		return this.buildid;
	}

	public void setBuildid(Integer buildid) {
		this.buildid = buildid;
	}

	public String getBuildname() {
		return this.buildname;
	}

	public void setBuildname(String buildname) {
		this.buildname = buildname;
	}

	public String getDetail() {
		return this.detail;
	}

	public void setDetail(String detail) {
		this.detail = detail;
	}

	public String getSortno() {
		return this.sortno;
	}

	public void setSortno(String sortno) {
		this.sortno = sortno;
	}

	public Timestamp getInsertTime() {
		return this.insertTime;
	}

	public void setInsertTime(Timestamp insertTime) {
		this.insertTime = insertTime;
	}

	public Timestamp getUpdateTime() {
		return this.updateTime;
	}

	public void setUpdateTime(Timestamp updateTime) {
		this.updateTime = updateTime;
	}

	public Integer getOperateId() {
		return this.operateId;
	}

	public void setOperateId(Integer operateId) {
		this.operateId = operateId;
	}

}

package com.orm.dto;

import java.sql.Timestamp;

public class FloorDto implements java.io.Serializable {

	private static final long serialVersionUID = 1L;
	private Integer floorid;
	private String floorname;
	private Integer floor;
	private String detail;
	private Integer buildId;
	private String sortno;
	private Timestamp insertTime;
	private Timestamp updateTime;
	private Integer operateId;

	public FloorDto() {
	}

	public FloorDto(Integer floorid) {
		this.floorid = floorid;
	}

	public Integer getFloorid() {
		return this.floorid;
	}

	public void setFloorid(Integer floorid) {
		this.floorid = floorid;
	}

	public String getFloorname() {
		return this.floorname;
	}

	public void setFloorname(String floorname) {
		this.floorname = floorname;
	}

	public String getDetail() {
		return this.detail;
	}

	public void setDetail(String detail) {
		this.detail = detail;
	}

	public Integer getBuildId() {
		return this.buildId;
	}

	public void setBuildId(Integer buildId) {
		this.buildId = buildId;
	}

	public String getSortno() {
		return this.sortno;
	}

	public void setSortno(String sortno) {
		this.sortno = sortno;
	}

	public Timestamp getInsertTime() {
		return this.insertTime;
	}

	public void setInsertTime(Timestamp insertTime) {
		this.insertTime = insertTime;
	}

	public Timestamp getUpdateTime() {
		return this.updateTime;
	}

	public void setUpdateTime(Timestamp updateTime) {
		this.updateTime = updateTime;
	}

	public Integer getOperateId() {
		return this.operateId;
	}

	public void setOperateId(Integer operateId) {
		this.operateId = operateId;
	}

	public Integer getFloor() {
		return floor;
	}

	public void setFloor(Integer floor) {
		this.floor = floor;
	}

}

package com.orm.dto;

import java.sql.Timestamp;

public class StoreDto implements java.io.Serializable {

	private static final long serialVersionUID = 1L;
	private Integer id;
	private String storename;
	private String storenameen;
	private String storeno;
	private Integer build_Id;
	private Integer floor_Id;
	private Integer area_Id;
	private Integer type_Id;
	private Integer point_Id;
	private String storeowner;
	private String area;
	private String remark;
	private String status;
	private String sortno;
	private Timestamp inserttime;
	private Timestamp updatetime;
	private Integer operateid;

	public StoreDto() {
	}

	public StoreDto(Integer id) {
		this.id = id;
	}

	public Integer getId() {
		return this.id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	public String getStorename() {
		return this.storename;
	}

	public void setStorename(String storename) {
		this.storename = storename;
	}

	public String getStorenameen() {
		return this.storenameen;
	}

	public void setStorenameen(String storenameen) {
		this.storenameen = storenameen;
	}

	public String getStoreno() {
		return this.storeno;
	}

	public void setStoreno(String storeno) {
		this.storeno = storeno;
	}

	public Integer getBuild_Id() {
		return this.build_Id;
	}

	public void setBuild_Id(Integer build_Id) {
		this.build_Id = build_Id;
	}

	public Integer getFloor_Id() {
		return this.floor_Id;
	}

	public void setFloor_Id(Integer floor_Id) {
		this.floor_Id = floor_Id;
	}

	public Integer getArea_Id() {
		return this.area_Id;
	}

	public void setArea_Id(Integer area_Id) {
		this.area_Id = area_Id;
	}

	public Integer getType_Id() {
		return this.type_Id;
	}

	public void setType_Id(Integer type_Id) {
		this.type_Id = type_Id;
	}

	public Integer getPoint_Id() {
		return this.point_Id;
	}

	public void setPoint_Id(Integer point_Id) {
		this.point_Id = point_Id;
	}

	public String getStoreowner() {
		return this.storeowner;
	}

	public void setStoreowner(String storeowner) {
		this.storeowner = storeowner;
	}

	public String getArea() {
		return this.area;
	}

	public void setArea(String area) {
		this.area = area;
	}

	public String getRemark() {
		return this.remark;
	}

	public void setRemark(String remark) {
		this.remark = remark;
	}

	public String getStatus() {
		return this.status;
	}

	public void setStatus(String status) {
		this.status = status;
	}

	public String getSortno() {
		return this.sortno;
	}

	public void setSortno(String sortno) {
		this.sortno = sortno;
	}

	public Timestamp getInserttime() {
		return this.inserttime;
	}

	public void setInserttime(Timestamp inserttime) {
		this.inserttime = inserttime;
	}

	public Timestamp getUpdatetime() {
		return this.updatetime;
	}

	public void setUpdatetime(Timestamp updatetime) {
		this.updatetime = updatetime;
	}

	public Integer getOperateid() {
		return this.operateid;
	}

	public void setOperateid(Integer operateid) {
		this.operateid = operateid;
	}

}

二、jdbc.properties

jdbc.driverClassName=com.microsoft.sqlserver.jdbc.SQLServerDriver
jdbc.url=jdbc:sqlserver://127.0.0.1:1433;databaseName=test
jdbc.username=sa
jdbc.password=admin@2013
jdbc.maxActive=50
jdbc.maxIdle=10
jdbc.maxWait=50
jdbc.defaultAutoCommit=true

三、Spring配置文件【beans.xml】

<?xml version="1.0" encoding="GB18030"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p"
	xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:aop="http://www.springframework.org/schema/aop"
	xmlns:tx="http://www.springframework.org/schema/tx" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.springframework.org/schema/beans  
      http://www.springframework.org/schema/beans/spring-beans-3.0.xsd  
      http://www.springframework.org/schema/context  
      http://www.springframework.org/schema/context/spring-context.xsd  
      http://www.springframework.org/schema/aop
      http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
      http://www.springframework.org/schema/tx
	  http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
      http://www.springframework.org/schema/mvc  
      http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd"
	default-autowire="byName" default-lazy-init="true">
	<!-- 属性文件读入 -->
	<bean id="propertyConfigurer"
		class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
		<property name="locations">
			<list>
				<value>classpath*:config/*.properties</value>
			</list>
		</property>
	</bean>
	<!-- 数据源定义,使用dbcp数据源 -->
	<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
		<property name="driverClassName" value="${jdbc.driverClassName}"></property>
		<property name="url" value="${jdbc.url}"></property>
		<property name="username" value="${jdbc.username}"></property>
		<property name="password" value="${jdbc.password}"></property>
		<property name="maxActive" value="${jdbc.maxActive}"></property>
		<property name="maxIdle" value="${jdbc.maxIdle}"></property>
		<property name="maxWait" value="${jdbc.maxWait}"></property>
		<property name="defaultAutoCommit" value="${jdbc.defaultAutoCommit}"></property>
	</bean>
	
	<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate" abstract="false"
        lazy-init="false" autowire="default" >
        <property name="dataSource">
            <ref bean="dataSource" />
        </property>
    </bean>

    <bean id="ormDao" class="com.orm.dao.impl.OrmDaoImpl">
       <property name="template">
          <ref bean="jdbcTemplate" />
       </property>
    </bean>
</beans>

四、web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
	http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
	<!--
		Spring ApplicationContext配置文件的路径,可使用通配符,多个路径用,号分隔
		此参数用于后面的Spring-Context loader
	-->
	<context-param>
		<param-name>contextConfigLocation</param-name>
		<param-value>classpath*:spring/*.xml</param-value>
	</context-param>
	<!--Spring ApplicationContext 载入 -->
	<listener>
		<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
	</listener>
	<!-- 著名 Character Encoding filter -->
	<filter>
		<filter-name>encodingFilter</filter-name>
		<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
		<init-param>
			<param-name>encoding</param-name>
			<param-value>GBK</param-value>
		</init-param>
	</filter>
	

	<!-- Spring 刷新Introspector防止内存泄露 -->
	<listener>
		<listener-class>
			org.springframework.web.util.IntrospectorCleanupListener</listener-class>
	</listener>
	<!--
		session超时定义,单位为分钟,清除服务端我们存储在Session中的对象,不清除Tomcat容器存储在Session中的对象
	-->
	<session-config>
		<session-timeout>30</session-timeout>
	</session-config>
</web-app>

五、数据库访问接口【OrmDao.java】

package com.orm.dao;

import java.util.List;
import java.util.Map;

import com.orm.dto.AreaDto;
import com.orm.dto.BuildingDto;
import com.orm.dto.FloorDto;
import com.orm.dto.StoreDto;

public interface OrmDao {
	public List<AreaDto> getAreaDtos();

	public List<AreaDto> getAreaDtos1();

	public Map<String, Object> getBuilds();

	public Map<String, Object> getFloors(String build);

	public Map<String, Object> getAreas(String build, String floor);

	public List<StoreDto> getStoreDtos(int buildid, int floorid, int areaid);

	public List<BuildingDto> getBuildingDto();

	public List<FloorDto> getFloorDtos(int buildid);

	public List<AreaDto> getAreaDto(int buildid, int floorid);

	public AreaDto getAreaDto(int id);

	public BuildingDto getBuildingDto(int buildId);

	public FloorDto getFloorDto(int floorId);

	public List<StoreDto> getAllStores();

	public String storeName(int storeId);

	public StoreDto getStoreById(int storeId);

	public int getCountStore();

	public void saveBuild(BuildingDto buildingDto);

	public void deleteBuildById(int buildid);

	public void updateBuildById(BuildingDto buildingDto);
}

六、数据库访问接口的实现类【OrmDaoImpl.java】

package com.orm.dao.impl;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;

import com.orm.dao.OrmDao;
import com.orm.dto.AreaDto;
import com.orm.dto.BuildingDto;
import com.orm.dto.FloorDto;
import com.orm.dto.StoreDto;

@SuppressWarnings({ "unchecked", "rawtypes" })
public class OrmDaoImpl implements OrmDao {
	private JdbcTemplate template;

	public JdbcTemplate getTemplate() {
		return template;
	}

	public void setTemplate(JdbcTemplate template) {
		this.template = template;
	}

	public List<AreaDto> getAreaDtos() {
		String sql = "select * from t_area ";
		return (List<AreaDto>) template.query(sql, new BeanPropertyRowMapper(AreaDto.class));
	}

	public List<AreaDto> getAreaDtos1() {
		String sql = "select * from t_area ";
		return (List<AreaDto>) template.query(sql, new AreaRowMapper());
	}

	public Map<String, Object> getBuilds() {
		String sql = "select buildid,buildname from t_building ";
		List<BuildingDto> list = this.template.query(sql, new BeanPropertyRowMapper(BuildingDto.class));
		Map<String, Object> map = new HashMap<String, Object>();
		for (BuildingDto build : list) {
			map.put(String.valueOf(build.getBuildid()), build.getBuildname());
		}
		return map;
	}

	public Map<String, Object> getFloors(String build) {
		String sql = "select floorid ,floorname from t_floor where build_id=?";
		List<FloorDto> list = this.template.query(sql, new Object[] { build }, new BeanPropertyRowMapper(FloorDto.class));
		Map<String, Object> map = new LinkedHashMap<String, Object>();
		for (FloorDto floorDto : list) {
			System.out.println(floorDto.getFloorid());
			map.put(String.valueOf(floorDto.getFloorid()), floorDto.getFloorname());
		}
		return map;
	}

	public Map<String, Object> getAreas(String build, String floor) {
		String sql = "select areaid ,area_name from t_area where build_id=? and floor_id=?";
		List<AreaDto> list = this.template.query(sql, new Object[] { build, floor }, new BeanPropertyRowMapper(AreaDto.class));
		Map<String, Object> map = new LinkedHashMap<String, Object>();
		for (AreaDto areaDto : list) {
			System.out.println(areaDto.getAreaid());
			map.put(String.valueOf(areaDto.getAreaid()), areaDto.getArea_name());
		}
		return map;
	}

	public List<StoreDto> getStoreDtos(int buildid, int floorid, int areaid) {
		String sql = "select * from t_store where build_id=? and floor_id=? and area_id=?";
		return (List<StoreDto>) template.query(sql, new Object[] { buildid, floorid, areaid }, new BeanPropertyRowMapper(
				StoreDto.class));
	}

	public List<BuildingDto> getBuildingDto() {
		String sql = "select * from t_building ";
		return (List<BuildingDto>) template.query(sql, new BeanPropertyRowMapper(BuildingDto.class));
	}

	public List<FloorDto> getFloorDtos(int buildid) {
		String sql = "select * from t_floor where build_id=? ";
		return (List<FloorDto>) template.query(sql, new Object[] { buildid }, new BeanPropertyRowMapper(FloorDto.class));
	}

	public List<AreaDto> getAreaDto(int buildid, int floorid) {
		String sql = "select * from t_area where build_id=? and floor_id=?";
		return (List<AreaDto>) template.query(sql, new Object[] { buildid, floorid }, new BeanPropertyRowMapper(AreaDto.class));
	}

	public AreaDto getAreaDto(int id) {
		String sql = "select * from t_area where areaid=?";
		return template.queryForObject(sql, new Object[] { id }, new BeanPropertyRowMapper(AreaDto.class));
	}

	public BuildingDto getBuildingDto(int buildId) {
		String sql = "select * from t_building where buildid=?";
		return template.queryForObject(sql, new Object[] { buildId }, new BeanPropertyRowMapper(BuildingDto.class));
	}

	public FloorDto getFloorDto(int floorId) {
		String sql = "select * from t_floor where floorid=?";
		return template.queryForObject(sql, new Object[] { floorId }, new BeanPropertyRowMapper(FloorDto.class));
	}

	public List<StoreDto> getAllStores() {
		String sql = "select * from t_store ";
		return (List<StoreDto>) template.query(sql, new BeanPropertyRowMapper(StoreDto.class));
	}

	public String storeName(int storeId) {
		String sql = "select storename from t_store where id=?";
		return template.queryForObject(sql, new Object[] { storeId }, String.class);
	}

	public StoreDto getStoreById(int storeInt) {
		String sql = "select * from t_store where id=?";
		return template.queryForObject(sql, new Object[] { storeInt }, new BeanPropertyRowMapper(StoreDto.class));
	}

	public int getCountStore() {
		String sql = "select count(id) from t_store";
		return this.template.queryForInt(sql);
	}

	public void saveBuild(BuildingDto buildingDto) {
	}

	public void deleteBuildById(int buildid) {
		String sql = "delete from t_store where id=?";
		this.template.update(sql, buildid);
	}

	public void updateBuildById(BuildingDto buildingDto) {

	}
}

class AreaRowMapper implements RowMapper {
	public Object mapRow(ResultSet rs, int index) throws SQLException {
		AreaDto areaDto = new AreaDto();
		areaDto.setAreaid(rs.getInt("areaid"));
		areaDto.setArea_name(rs.getString("area_name"));
		areaDto.setArea_detail(rs.getString("area_detail"));
		areaDto.setBuild_id(rs.getInt("build_id"));
		areaDto.setFloor_id(rs.getInt("floor_id"));
		areaDto.setInsert_time(rs.getTimestamp("insert_time"));
		areaDto.setOperate_id(rs.getInt("operate_id"));
		areaDto.setUpdate_time(rs.getTimestamp("update_time"));
		areaDto.setRegion_name(rs.getString("region_name"));
		areaDto.setSortno(rs.getString("sortno"));
		return areaDto;
	}
}

七、测试类

package com.orm.test;

import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.orm.dao.OrmDao;
import com.orm.dto.AreaDto;

public class AreaTest{
	private ApplicationContext ctx = null;
	private OrmDao ormDao = null;
	@Before
	public void setUp() throws Exception {
		ctx = new ClassPathXmlApplicationContext("classpath:spring/beans.xml");
		ormDao = (OrmDao) ctx.getBean("ormDao");
	}
	@Test
	public void getAreaDtosTest(){
		List<AreaDto> list = this.ormDao.getAreaDtos();
		for(AreaDto areaDto : list){
			System.out.println(areaDto.getArea_name());
		}
		System.out.println(list.size());
	}
	@Test
	public void getAreaDtosTest1(){
		List<AreaDto> list = this.ormDao.getAreaDtos1();
		for(AreaDto areaDto : list){
			System.out.println(areaDto.getArea_name());
		}
		System.out.println(list.size());
	}
	@Test
	public void getBuildsTest(){
		Map<String, Object> builds = this.ormDao.getBuilds();
		Iterator<String> keys = builds.keySet().iterator();
		String key = "";
		while(keys.hasNext()){
			key = keys.next();
			System.out.println("key = "+key+",value = "+builds.get(key));
		}
	}
	@Test
	public void getFloorsTest(){
		Map<String, Object> floors = this.ormDao.getFloors("1");
		System.out.println(floors);
		Set<Entry<String, Object>> floorSet = floors.entrySet();
		for(Entry floor : floorSet){
			System.out.println(floor.getKey()+","+floor.getValue());
		}
	}
	@Test
	public void getAreasTest(){
		Map<String, Object> areas = this.ormDao.getAreas("1","1");
		System.out.println(areas);
		Set<Entry<String, Object>> areaSet = areas.entrySet();
		for(Entry area : areaSet){
			System.out.println(area.getKey()+","+area.getValue());
		}
	}
	@Test
	public void getCountStoreTest(){
		System.out.println(this.ormDao.getCountStore());
	}
}

说明:

JdbcTemplate提供的方法很多如:queryForXXX,可以将查询结果以int、long、Object、List、Map来返回,这里有几个需要注意的:

下面是针对老版本的Spring1.2.x的JdbcTemplate操作:使用RowMapperResultReader对象来处理

class UserRowMapper implements RowMapper {
    public Object mapRow(ResultSet rs, int index) throws SQLException {
        User user = new User();

        user.setId(rs.getString("user_id"));
        user.setName(rs.getString("name"));
        user.setSex(rs.getString("sex").charAt(0));
        user.setAge(rs.getInt("age"));

        return user;
    }
}

public List findAllByRowMapperResultReader() {
    String sql = "SELECT * FROM USER";
    return jdbcTemplate.query(sql, new RowMapperResultReader(new UserRowMapper()));
}

但是在Spring2及以上的版本中却没有RowMapperResultReader这个对象,所以直接传替封装类来使用:

public List<AreaDto> getAreaDtos1() {
		String sql = "select * from t_area ";
		return (List<AreaDto>) template.query(sql, new AreaRowMapper());
	}
class AreaRowMapper implements RowMapper {
	public Object mapRow(ResultSet rs, int index) throws SQLException {
		AreaDto areaDto = new AreaDto();
		areaDto.setAreaid(rs.getInt("areaid"));
		areaDto.setArea_name(rs.getString("area_name"));
		areaDto.setArea_detail(rs.getString("area_detail"));
		areaDto.setBuild_id(rs.getInt("build_id"));
		areaDto.setFloor_id(rs.getInt("floor_id"));
		areaDto.setInsert_time(rs.getTimestamp("insert_time"));
		areaDto.setOperate_id(rs.getInt("operate_id"));
		areaDto.setUpdate_time(rs.getTimestamp("update_time"));
		areaDto.setRegion_name(rs.getString("region_name"));
		areaDto.setSortno(rs.getString("sortno"));
		return areaDto;
	}
}

queryForList方法

此方法返回List数据,但是注意List中的数据却是Map形式,类似:[{AREAID=1, AREA_NAME=1楼报名咨询区}, {AREAID=2, AREA_NAME=2楼教学区}, {AREAID=3, AREA_NAME=3楼课外辅导区}],其中字段名为key,字段值为value


queryForMap方法

返回Map类型的数据,数据格式为{AREAID=1, AREA_NAME=1楼报名咨询区},注意:此方法必须只能返回一条记录,如果查询有多条记录就会报错:“org.springframework.dao.IncorrectResultSizeDataAccessException: Incorrect result size: expected 1, actual 2”


如果需要查询数据库返回一个List<T>类型的对象该如何实现?

目前有两种形式:

第一种:

public List<AreaDto> getAreaDtos1() {
		String sql = "select * from t_area ";
		return (List<AreaDto>) template.query(sql, new AreaRowMapper());
	}
class AreaRowMapper implements RowMapper {
	public Object mapRow(ResultSet rs, int index) throws SQLException {
		AreaDto areaDto = new AreaDto();
		areaDto.setAreaid(rs.getInt("areaid"));
		areaDto.setArea_name(rs.getString("area_name"));
		areaDto.setArea_detail(rs.getString("area_detail"));
		areaDto.setBuild_id(rs.getInt("build_id"));
		areaDto.setFloor_id(rs.getInt("floor_id"));
		areaDto.setInsert_time(rs.getTimestamp("insert_time"));
		areaDto.setOperate_id(rs.getInt("operate_id"));
		areaDto.setUpdate_time(rs.getTimestamp("update_time"));
		areaDto.setRegion_name(rs.getString("region_name"));
		areaDto.setSortno(rs.getString("sortno"));
		return areaDto;
	}
}

第二种:

public List<AreaDto> getAreaDtos() {
		String sql = "select * from t_area ";
		System.out.println(template.queryForList(sql));
		return (List<AreaDto>) template.query(sql, new BeanPropertyRowMapper(AreaDto.class));
	}

很显然采用第二种会更简单。


转载于:http://www.16boke.com/article/detail/15



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