JDBC的Template概念
JDBC的Template基本使用
环境搭建
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.19</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-beans</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aop</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
</dependencies>
<?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"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
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.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx.xsd">
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.cj.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/selection_course?useUnicode=true&characterEncoding=UTF-8&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=GMT%2B8"/>
<property name="username" value="root"/>
<property name="password" value="1234"/>
</bean>
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource" ref="dataSource"/>
</bean>
</beans>
execute方法
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.JdbcTemplate;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
public class Test {
private JdbcTemplate jdbcTemplate;
{
ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");
jdbcTemplate = (JdbcTemplate)context.getBean("jdbcTemplate");
}
@org.junit.Test
public void testExecute(){
jdbcTemplate.execute("create table user1(id int, name varchar(20))");
}
update与batchUpdate方法
@org.junit.Test
public void testUpdate(){
String sql = "INSERT INTO student(name,sex) VALUES(?,?)";
jdbcTemplate.update(sql, new Object[]{"张飞","男"});
}
@org.junit.Test
public void testUpdate2(){
String sql = "UPDATE student SET sex=? WHERE id=?";
jdbcTemplate.update(sql, "女",1);
}
@org.junit.Test
public void testBatchUpdate(){
String[] sqls={
"INSERT INTO student(name,sex) VALUES('关羽','女')",
"INSERT INTO student(name,sex) VALUES('刘备','男')",
"UPDATE student SET sex='男' WHERE id=1"
};
jdbcTemplate.batchUpdate(sqls);
}
@org.junit.Test
public void testBatchUpdate2(){
String sql = "INSERT INTO selection(student,course) VALUES(?,?)";
List<Object[]> list = new ArrayList<Object[]>();
list.add(new Object[]{1, 1001});
list.add(new Object[]{1,1003});
jdbcTemplate.batchUpdate(sql,list);
}
query与queryXXX方法
package com.jesse.sc.entity;
import java.util.Date;
public class Student {
private int id;
private String name;
private String sex;
private Date born;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public Date getBorn() {
return born;
}
public void setBorn(Date born) {
this.born = born;
}
@Override
public String toString() {
return "Student{" +
"id=" + id +
", name='" + name + '\'' +
", sex='" + sex + '\'' +
", born=" + born +
'}';
}
}
@org.junit.Test
public void testQuerySimple1(){
String sql = "SELECT count(*) FROM student";
int count = jdbcTemplate.queryForObject(sql,Integer.class);
System.out.println(count);
}
@org.junit.Test
public void testQuerySimple2(){
String sql = "SELECT name FROM student WHERE sex=?";
List<String> names = jdbcTemplate.queryForList(sql,String.class,"男");
System.out.println(names);
}
@org.junit.Test
public void testQueryMap1(){
String sql = "SELECT * FROM student WHERE id = ?";
Map<String,Object> stu = jdbcTemplate.queryForMap(sql, 1);
System.out.println(stu);
}
@org.junit.Test
public void testQueryMap2(){
String sql = "SELECT * FROM student";
List<Map<String,Object>> stus = jdbcTemplate.queryForList(sql);
System.out.println(stus);
}
@org.junit.Test
public void testQueryEntity1(){
String sql = "SELECT * FROM student WHERE id = ?";
Student stu = jdbcTemplate.queryForObject(sql, new StudentRowMapper(), 1);
System.out.println(stu);
}
@org.junit.Test
public void testQueryEntity2(){
String sql = "SELECT * FROM student";
List<Student> stus = jdbcTemplate.query(sql, new StudentRowMapper());
System.out.println(stus);
}
private class StudentRowMapper implements RowMapper<Student>{
public Student mapRow(ResultSet resultSet, int i) throws SQLException {
Student stu = new Student();
stu.setId(resultSet.getInt("id"));
stu.setName(resultSet.getString("name"));
stu.setSex(resultSet.getString("sex"));
stu.setBorn(resultSet.getDate("born"));
return stu;
}
}
Example
package com.jesse.sc.entity;
import java.util.Date;
public class Student {
private int id;
private String name;
private String sex;
private Date born;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public Date getBorn() {
return born;
}
public void setBorn(Date born) {
this.born = born;
}
@Override
public String toString() {
return "Student{" +
"id=" + id +
", name='" + name + '\'' +
", sex='" + sex + '\'' +
", born=" + born +
'}';
}
}
package com.jesse.sc.dao;
import com.jesse.sc.entity.Student;
import java.util.List;
public interface StudentDao {
void insert(Student stu);
void update(Student stu);
void delete(int id);
Student select(int id);
List<Student> selectAll();
}
package com.jesse.sc.dao.impl;
import com.jesse.sc.dao.StudentDao;
import com.jesse.sc.entity.Student;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.stereotype.Repository;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
@Repository
public class StudentDaoImpl implements StudentDao {
@Autowired
private JdbcTemplate jdbcTemplate;
public void insert(Student stu) {
String sql = "INSERT INTO student(name,sex,born) VALUES(?,?,?)";
jdbcTemplate.update(sql, stu.getName(), stu.getSex(), stu.getBorn());
}
public void update(Student stu) {
String sql = "UPDATE student SET name=?,sex=?,born=? WHERE id=?";
jdbcTemplate.update(sql,stu.getName(),stu.getSex(),stu.getBorn(),stu.getId());
}
public void delete(int id) {
String sql = "DELETE FROM student WHERE id=?";
jdbcTemplate.update(sql,id);
}
public Student select(int id) {
String sql = "SELECT * FROM student WHERE id=?";
return jdbcTemplate.queryForObject(sql, new StudentRowMapper(), id);
}
public List<Student> selectAll() {
String sql = "SELECT * FROM student WHERE id=?";
return jdbcTemplate.query(sql, new StudentRowMapper());
}
private class StudentRowMapper implements RowMapper<Student> {
public Student mapRow(ResultSet resultSet, int i) throws SQLException {
Student stu = new Student();
stu.setId(resultSet.getInt("id"));
stu.setName(resultSet.getString("name"));
stu.setSex(resultSet.getString("sex"));
stu.setBorn(resultSet.getDate("born"));
return stu;
}
}
}
优缺点
- 优点：对比原生JDBC，更加方便灵活
- 缺点：SQL与Java代码掺杂，功能不够丰富（引出MaBatis）
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