数据库:
create table school( id int(11) not null auto_increment comment '主键', name varchar(20) comment '学校名称', address varchar(100) comment '学校地址', create_time datatime comment '数据上传时间', primary key (id) )
实体类:
package com.test.entity; public class School{ private Integer id;//主键id private String name;//学校名称 private String address//学校地址 private Date createTime//数据上传时间 }
现在开始添加功能
mybaties: schooMapper.xml:
<mapper namespace="com.test.dao.SchoolMapper"> <resultMap type="com.test.entity.School" id="schoolMap"> <id column="id" property="id" jdbcType="INTEGER"/> <result column="name" property="name" jdbcType="VARCHAR"/> <result column="address" property="address" jdbcType="VARCHAR"/> <result column="create_time" property="createTime" jdbcType="DATE"/> </resultMap> <sql id="s_sql" > name,address,create_time </sql> <!-- 普通的插入数据不能返回id --> <insert id="save" parameterType="com.test.entity.School"> insert into school (<include refid="s_sql"/>)values(#{name},#{address},#{createTime}) </insert> </mapper>
下面的可以返回id,但是需要主键为自增(id在这儿要不要都可以)
<!-- 插入数据返回id,方法一 这个需要是自增的id --> <insert id="saveReturnIdOne" parameterType="com.test.entity.School" useGeneratedKeys="true" keyProperty="id"> insert into school (id,<include refid="s_sql"/>)values(#{id},#{name},#{address},#{createTime}) </insert>
这个第二种添加可以返回主键id的,好像是返回添加的最后一个id--不需要自增(这个不确切知道)
<!-- 插入数据返回id,方法一 这个返回最后添加的一条id --> <insert id="saveReturnIdTwo" parameterType="com.test.entity.School" useGeneratedKeys="true"> insert into school (<include refid="s_sql"/>)values(#{name},#{address},#{createTime}) <selectKey keyProperty="id" resultType="int" order="AFTER" > SELECT LAST_INSERT_ID() AS VALUE </selectKey> </insert>
--------现在开始批量添加
<!-- 这个批量插入数据 --> <insert id="bathSave" parameterType="java.util.List"> insert into school (<include refid="s_sql"/>)values <foreach collection="list" index="index" item="l" separator=","> (#{l.name},#{l.address},#{l.createTime}) </foreach> </insert>
java代码:
public int save(School test); public int saveReturnIdOne(School test); public int saveReturnIdTwo(School test); public void bathSave(List<School> list);
现在开始删除功能
<!-- 这个普通删除数据 --> <delete id="deleteById" parameterType="java.lang.Integer"> delete from school where id=#{id} </delete> <!-- 这个批量删除数据 --> <delete id="bathDelete" parameterType="java.util.List"> delete from school where id in <foreach collection="list" index="index" item="l" open="(" close=")" separator=","> #{l} </foreach> </delete> <delete id="bathDeleteTwo" parameterType="java.util.List"> delete from school where id in (${id}) </delete>
java代码:
public int deleteById(Integer list); public int bathDelete(List<Integer> list); public int bathDeleteTwo(Map<String,String>id);
现在开始修改功能
<!-- 普通修改 --> <update id="update" parameterType="com.test.entity.School"> update school set name=#{name}, address=#{address}, create_time=#{createTime} where id=#{id,jdbcType=INTEGER} </update> <!-- 有选择性的修改数据 --> <update id="updateSet" parameterType="com.test.entity.School"> update school <set> <if test="name != null"> name=#{name}, </if> <if test="address !=null "> address=#{address}, </if> <if test="createTime !=null "> create_time=#{createTime} </if> </set> where id=#{id} </update> <!-- 这个批量修改需要在数据库的url后面拼接 &allowMultiQueries=true 意思是同时执行多条,否则报错 --> <update id="bathUpdate" parameterType="java.util.List"> <foreach collection="list" index="index" item="l" open="" close="" separator=";"> update school <set> <if test="l.name != null"> name=#{l.name}, </if> <if test="l.address !=null "> address=#{l.address}, </if> <if test="l.createTime !=null "> create_time=#{l.createTime} </if> </set> where id=#{l.id,jdbcType=INTEGER} </foreach> </update> <!-- 还有一种批量修改多个id,即 id in(1,2,3,4) 方法类同批量删除,这里不写了 -->
java代码:
public void update(TestEntity test); public void updateSet(TestEntity test); public void bathUpdate(List<TestEntity> list);
现在开始查询功能(批量查询和删除的一样)
xml:
<!-- 根据id查询一条 --> <select id="getById" resultMap="schoolMap" > select id,<include refid="s_sql"/> from school where id =#{id} </select> <!-- 根据地址分页查询 --> <select id="getLimit" resultMap="schoolMap" parameterType="java.util.Map"> select id,<include refid="s_sql"/> from school where address=#{address} limit #{begin},#{end} </select> <!-- 根据名字模糊查询 --> <select id="getLikeName" resultMap="schoolMap"> select id,<include refid="s_sql"/> from school where name like concat('%',#{name},'%') </select> <!-- 根据名字模糊查询所有id集合 --> <select id="getIdsLikeName" resultType="java.lang.String"> select group_concat(id) from school where name like concat('%',#{name},'%') </select> <!-- 根据实体类属性选择查询 --> <select id="getWhere" resultMap="schoolMap"> select id,<include refid="s_sql"/> from school <where> <if test="id != null"> id=#{id} </if> <if test="name != null"> and name=#{name} </if> <if test="address !=null "> and address=#{address} </if> <if test="createTime !=null "> and create_time=#{createTime} </if> </where> </select>
java代码:
public School getById(Integer id); public List<School > getLimit(Map<String, Object> map); public List<School > getLikeName(String name); public String getIdsLikeName(String name); public List<School > getWhere(School test);
下面是从其它地方看到:
同时执行多条sql的办法:
1、最简单的办法:在MySQL的连接字符串中设置allowMultiQueries参数置为true。(只有MySQL Connector/J 3.1.1以上版本才支持) 。例如:在jdbc下设置连接字符串的时候设成如下的形式:
jdbc:mysql://192.168.3.180/sample?user=root&password=&allowMultiQueries=true就可以执行多条语句了
在odbc下也是可以设置的,方法如下:
设置 ODBC -- 配置 --Detials -- Flags 3 -- 钩上 Allow multiple statements,这样就可以了。
结论:第一种方式最简单。
2、在程序中对SQL语句以分号拆分成多条SQL语句,然后使用Statement的addBatch方法,最后executeBatch就行。
希望对以后遇到此类问题的朋友有所帮助。
关于Statement的execute(String sql)语句能够同时执行多条SQL语句, 可以看MySQL自带的测试例子:
可查看testsuite.regression包下的ResultSetRegressionTest类: 这个可以查看:MySQL for Java的SQL注入测试
public class ResultSetRegressionTest extends BaseTestCase { public void testBug33678() throws Exception { if (!versionMeetsMinimum(4, 1)) { return; } createTable("testBug33678", "(field1 INT)"); // allowMultiQueries=true设置 Connection multiConn = getConnectionWithProps("allowMultiQueries=true"); Statement multiStmt = multiConn.createStatement(); try { multiStmt.setFetchSize(Integer.MIN_VALUE); // 一次性执行多条SQL语句 multiStmt.execute("SELECT 1 UNION SELECT 2; INSERT INTO testBug33678 VALUES (1); UPDATE testBug33678 set field1=2; INSERT INTO testBug33678 VALUES(3); UPDATE testBug33678 set field1=2 WHERE field1=3; UPDATE testBug33678 set field1=2; SELECT 1"); // 以下代码省略... } }
还可以查看英文API Mapper XML Files