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Spring使用JdbcTemplate实现对数据库操作

2017-08-16 21:09 555 查看

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

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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;
    }

}

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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;
    }

}

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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;
    }

}

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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

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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】

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<?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">
    
    <bean id="propertyConfigurer"
        class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="locations">
            <list>
                <value>classpath*:config/*.properties</value>
            </list>
        </property>
    </bean>
    
    <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

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<?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">
    
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath*:spring/*.xml</param-value>
    </context-param>
    
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    
    <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>


    
    <listener>
        <listener-class>
            org.springframework.web.util.IntrospectorCleanupListener</listener-class>
    </listener>
    
    <session-config>
        <session-timeout>30</session-timeout>
    </session-config>
</web-app>

五、数据库访问接口【OrmDao.java】

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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】

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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

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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

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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：

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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：

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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：

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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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