Spring入门第二十五课
使用具名参数
直接看代码:
db.properties
jdbc.user=root
jdbc.password=logan123
jdbc.driverClass=com.mysql.jdbc.Driver
jdbc.jdbcUrl=jdbc:mysql://localhost:3306/selective-courses-system
jdbc.initPoolSize=5
jdbc.maxPoolSize=10
applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd"> <!-- 导入资源文件 --> <context:property-placeholder location="classpath:db.properties"/> <!-- 配置C3P0数据源 --> <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"> <property name="user" value="${jdbc.user}"></property> <property name="password" value="${jdbc.password}"></property> <property name="jdbcUrl" value="${jdbc.jdbcUrl}"></property> <property name="driverClass" value="${jdbc.driverClass}"></property> <property name="initialPoolSize" value="${jdbc.initPoolSize}"></property> <property name="maxPoolSize" value="${jdbc.maxPoolSize}"></property> </bean> <!-- 配置Spring的JDBCTemplate --> <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate"> <property name="dataSource" ref="dataSource"></property> </bean> <!-- 配置NamedParameterJdbcTemplate,该对象可以使用具名参数,其没有无参的构造器,所以必须为其构造器指定参数 --> <bean id="namedParameterJdbcTemplate" class="org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate"> <constructor-arg ref="dataSource"></constructor-arg> </bean> </beans>
package logan.study.spring.jdbc; public class Student { String student_id; String student_name; String card_id; String student_class; String sex; String password; String perovince; String address; String tel; String interests; public String getStudent_id() { return student_id; } public void setStudent_id(String student_id) { this.student_id = student_id; } public String getStudent_name() { return student_name; } public void setStudent_name(String student_name) { this.student_name = student_name; } public String getCard_id() { return card_id; } public void setCard_id(String card_id) { this.card_id = card_id; } public String getStudent_class() { return student_class; } public void setStudent_class(String student_class) { this.student_class = student_class; } public String getSex() { return sex; } public void setSex(String sex) { this.sex = sex; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getPerovince() { return perovince; } public void setPerovince(String perovince) { this.perovince = perovince; } public String getAddress() { return address; } public void setAddress(String address) { this.address = address; } public String getTel() { return tel; } public void setTel(String tel) { this.tel = tel; } public String getInterests() { return interests; } public void setInterests(String interests) { this.interests = interests; } @Override public String toString() { return "Student [student_id=" + student_id + ", student_name=" + student_name + ", card_id=" + card_id + ", student_class=" + student_class + ", sex=" + sex + ", password=" + password + ", perovince=" + perovince + ", address=" + address + ", tel=" + tel + ", interests=" + interests + "]"; } }
package logan.study.spring.jdbc; import static org.junit.Assert.*; import java.sql.SQLException; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import javax.sql.DataSource; import org.junit.Test; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; import org.springframework.jdbc.core.BeanPropertyRowMapper; import org.springframework.jdbc.core.JdbcTemplate; import org.springframework.jdbc.core.RowMapper; import org.springframework.jdbc.core.namedparam.BeanPropertySqlParameterSource; import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate; import org.springframework.jdbc.core.namedparam.SqlParameterSource; public class JDBCTest { private ApplicationContext ctx = null; private JdbcTemplate jdbcTemplate; private NamedParameterJdbcTemplate namedParameterJdbcTemplate; { ctx = new ClassPathXmlApplicationContext("applicationContext.xml"); jdbcTemplate = (JdbcTemplate) ctx.getBean("jdbcTemplate"); namedParameterJdbcTemplate = ctx.getBean(NamedParameterJdbcTemplate.class); } @Test public void testDataSource() throws SQLException { DataSource dataSource = (DataSource) ctx.getBean("dataSource"); System.out.println(dataSource.getConnection()); } /** * 使用具名参数可以使用update(String sql, SqlParameterSource paramSource)方法进行更新 * 1.SQL语句中的参数名和类的属性名一样。 * 2.使用SqlParameterSource的BeanPropertySqlParameterSource实现类作为参数 */ @Test public void testNamedParameterJdbcTemplate2(){ String sql = "INSERT INTO student_info (student_id,student_name) VALUES(:student_id,:student_name)"; Student student = new Student(); student.setStudent_id("100"); student.setStudent_name("小周"); SqlParameterSource paramSource = new BeanPropertySqlParameterSource(student); namedParameterJdbcTemplate.update(sql, paramSource); } /** * 可以为参数起名字 * 1.好处:若有多个参数,则不用再去对应位置,直接对应参数名,便于维护 * 2.缺点:较为麻烦 */ @Test public void testNamedParameterJdbcTemplate(){ String sql = "INSERT INTO student_info (student_id,student_name) VALUES(:si,:sn)"; Map<String,Object> paramMap = new HashMap<>(); paramMap.put("si", "HH"); paramMap.put("sn", "小楼"); namedParameterJdbcTemplate.update(sql, paramMap); } /** * 获取单个列的值,或者做统计查询 */ @Test public void testQueryForObject2(){ String sql = "SELECT count(*) FROM student_info"; long count = jdbcTemplate.queryForObject(sql, Long.class); System.out.println(count); } /** * 查到实体类的集合 */ @Test public void testQueryForList(){ String sql = "SELECT student_id,student_name,card_id,class student_class,sex,password,perovince,tel,interests from student_info where student_id > ?"; RowMapper<Student> rowMapper = new BeanPropertyRowMapper<>(Student.class); List<Student> students = jdbcTemplate.query(sql, rowMapper,5); System.out.println(students); } /** * 从数据库中获取一条记录,实际得到对应的一个对象 * 注意不是调用queryForObject(String sql,Class<Student> requiredType,Object... args)方法! * 而是调用queryForObject(String sql,RowMapper<Student> rowMapper,Object... args)方法! * 1.其中的RowMapper指定如何去映射结果集的行,常用的实现类为BeanPropertyRowMapper * 2.使用SQL中列的别名完成列名和类的属性名的映射。例如class student_class * 3.不支持级联框架,JdbcTemplate到底是一个JDBC的小工具,而不是ORM框架。 */ @Test public void testQueryForObject(){ String sql = "SELECT student_id,student_name,card_id,class student_class,sex,password,perovince,tel,interests from student_info where student_id=?"; RowMapper<Student> rowMapper = new BeanPropertyRowMapper<>(Student.class); Student student = jdbcTemplate.queryForObject(sql, rowMapper,1); System.out.println(student); } /** * 执行批量更新,批量INSERT,UPDATE,DELETE * */ @Test public void testBatchUpdate(){ String sql = "INSERT INTO student_info (student_id,student_name) VALUES(?,?)"; List<Object[]> pss = new ArrayList<Object[]>(); pss.add(new Object[]{"009","AA"}); pss.add(new Object[]{"010","BB"}); pss.add(new Object[]{"011","CC"}); pss.add(new Object[]{"012","DD"}); pss.add(new Object[]{"013","EE"}); pss.add(new Object[]{"014","FF"}); pss.add(new Object[]{"015","GG"}); jdbcTemplate.batchUpdate(sql, pss); } /** * 执行INSERT,UPDATE,DELETE */ @Test public void testUpdate(){ String sql = "UPDATE student_info SET student_name = ? WHERE student_id = ?"; jdbcTemplate.update(sql,"小黑","002"); } }
心再坚强也不要独自飞翔