在使用普通的 JDBC 数据库时,就会很麻烦的写不必要的代码来处理异常,打开和关闭数据库连接等。但 Spring JDBC 框架负责所有的低层细节,从开始打开连接,准备和执行 SQL 语句,处理异常,处理事务,到最后关闭连接。
所以当从数据库中获取数据时,你所做的是定义连接参数,指定要执行的 SQL 语句,每次迭代完成所需的工作。
Spring JDBC 示例
- 数据访问对象接口文件 StudentDAO.java 的内容:
package com.tutorialspoint;
import java.util.List;
import javax.sql.DataSource;
public interface StudentDAO {
/**
* This is the method to be used to initialize
* database resources ie. connection.
*/
public void setDataSource(DataSource ds);
/**
* This is the method to be used to create
* a record in the Student table.
*/
public void create(String name, Integer age);
/**
* This is the method to be used to list down
* a record from the Student table corresponding
* to a passed student id.
*/
public Student getStudent(Integer id);
/**
* This is the method to be used to list down
* all the records from the Student table.
*/
public List<Student> listStudents();
/**
* This is the method to be used to delete
* a record from the Student table corresponding
* to a passed student id.
*/
public void delete(Integer id);
/**
* This is the method to be used to update
* a record into the Student table.
*/
public void update(Integer id, Integer age);
}
- Student.java 文件的内容:
package com.tutorialspoint;
public class Student {
private Integer age;
private String name;
private Integer id;
public void setAge(Integer age) {
this.age = age;
}
public Integer getAge() {
return age;
}
public void setName(String name) {
this.name = name;
}
public String getName() {
return name;
}
public void setId(Integer id) {
this.id = id;
}
public Integer getId() {
return id;
}
}
- StudentMapper.java 文件的内容:
package com.tutorialspoint;
import java.sql.ResultSet;
import java.sql.SQLException;
import org.springframework.jdbc.core.RowMapper;
public class StudentMapper implements RowMapper<Student> {
public Student mapRow(ResultSet rs, int rowNum) throws SQLException {
Student student = new Student();
student.setId(rs.getInt("id"));
student.setName(rs.getString("name"));
student.setAge(rs.getInt("age"));
return student;
}
}
- 为定义的 DAO 接口 StudentDAO 的实现类文件 StudentJDBCTemplate.java:
package com.tutorialspoint;
import java.util.List;
import javax.sql.DataSource;
import org.springframework.jdbc.core.JdbcTemplate;
public class StudentJDBCTemplate implements StudentDAO {
private DataSource dataSource;
private JdbcTemplate jdbcTemplateObject;
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
this.jdbcTemplateObject = new JdbcTemplate(dataSource);
}
public void create(String name, Integer age) {
String SQL = "insert into Student (name, age) values (?, ?)";
jdbcTemplateObject.update( SQL, name, age);
System.out.println("Created Record Name = " + name + " Age = " + age);
return;
}
public Student getStudent(Integer id) {
String SQL = "select * from Student where id = ?";
Student student = jdbcTemplateObject.queryForObject(SQL,
new Object[]{id}, new StudentMapper());
return student;
}
public List<Student> listStudents() {
String SQL = "select * from Student";
List <Student> students = jdbcTemplateObject.query(SQL,
new StudentMapper());
return students;
}
public void delete(Integer id){
String SQL = "delete from Student where id = ?";
jdbcTemplateObject.update(SQL, id);
System.out.println("Deleted Record with ID = " + id );
return;
}
public void update(Integer id, Integer age){
String SQL = "update Student set age = ? where id = ?";
jdbcTemplateObject.update(SQL, age, id);
System.out.println("Updated Record with ID = " + id );
return;
}
}
- 配置文件 Beans.xml 的内容:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
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 ">
<!-- Initialization for data source -->
<bean id="dataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/TEST"/>
<property name="username" value="root"/>
<property name="password" value="password"/>
</bean>
<!-- Definition for studentJDBCTemplate bean -->
<bean id="studentJDBCTemplate"
class="com.tutorialspoint.StudentJDBCTemplate">
<property name="dataSource" ref="dataSource" />
</bean>
</beans>
- MainApp.java 文件的内容:
package com.tutorialspoint;
import java.util.List;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.tutorialspoint.StudentJDBCTemplate;
public class MainApp {
public static void main(String[] args) {
ApplicationContext context =
new ClassPathXmlApplicationContext("Beans.xml");
StudentJDBCTemplate studentJDBCTemplate =
(StudentJDBCTemplate)context.getBean("studentJDBCTemplate");
System.out.println("------Records Creation--------" );
studentJDBCTemplate.create("Zara", 11);
studentJDBCTemplate.create("Nuha", 2);
studentJDBCTemplate.create("Ayan", 15);
System.out.println("------Listing Multiple Records--------" );
List<Student> students = studentJDBCTemplate.listStudents();
for (Student record : students) {
System.out.print("ID : " + record.getId() );
System.out.print(", Name : " + record.getName() );
System.out.println(", Age : " + record.getAge());
}
System.out.println("----Updating Record with ID = 2 -----" );
studentJDBCTemplate.update(2, 20);
System.out.println("----Listing Record with ID = 2 -----" );
Student student = studentJDBCTemplate.getStudent(2);
System.out.print("ID : " + student.getId() );
System.out.print(", Name : " + student.getName() );
System.out.println(", Age : " + student.getAge());
}
}
- 输出的消息:
------Records Creation--------
Created Record Name = Zara Age = 11
Created Record Name = Nuha Age = 2
Created Record Name = Ayan Age = 15
------Listing Multiple Records--------
ID : 1, Name : Zara, Age : 11
ID : 2, Name : Nuha, Age : 2
ID : 3, Name : Ayan, Age : 15
----Updating Record with ID = 2 -----
Updated Record with ID = 2
----Listing Record with ID = 2 -----
ID : 2, Name : Nuha, Age : 20
SQL 的存储过程
SimpleJdbcCall 类可以被用于调用一个包含 IN 和 OUT 参数的存储过程。你可以在处理任何一个 RDBMS 时使用这个方法,就像 Apache Derby, DB2, MySQL, Microsoft SQL Server, Oracle,和 Sybase。
- 数据访问对象接口文件 StudentDAO.java 的内容:
package com.tutorialspoint;
import java.util.List;
import javax.sql.DataSource;
public interface StudentDAO {
/**
* This is the method to be used to initialize
* database resources ie. connection.
*/
public void setDataSource(DataSource ds);
/**
* This is the method to be used to create
* a record in the Student table.
*/
public void create(String name, Integer age);
/**
* This is the method to be used to list down
* a record from the Student table corresponding
* to a passed student id.
*/
public Student getStudent(Integer id);
/**
* This is the method to be used to list down
* all the records from the Student table.
*/
public List<Student> listStudents();
}
- Student.java 文件的内容:
package com.tutorialspoint;
public class Student {
private Integer age;
private String name;
private Integer id;
public void setAge(Integer age) {
this.age = age;
}
public Integer getAge() {
return age;
}
public void setName(String name) {
this.name = name;
}
public String getName() {
return name;
}
public void setId(Integer id) {
this.id = id;
}
public Integer getId() {
return id;
}
}
- StudentMapper.java 文件的内容:
package com.tutorialspoint;
import java.sql.ResultSet;
import java.sql.SQLException;
import org.springframework.jdbc.core.RowMapper;
public class StudentMapper implements RowMapper<Student> {
public Student mapRow(ResultSet rs, int rowNum) throws SQLException {
Student student = new Student();
student.setId(rs.getInt("id"));
student.setName(rs.getString("name"));
student.setAge(rs.getInt("age"));
return student;
}
}
- 实现类文件 StudentJDBCTemplate.java,定义了 DAO 接口 StudentDAO:
package com.tutorialspoint;
import java.util.Map;
import javax.sql.DataSource;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.namedparam.MapSqlParameterSource;
import org.springframework.jdbc.core.namedparam.SqlParameterSource;
import org.springframework.jdbc.core.simple.SimpleJdbcCall;
public class StudentJDBCTemplate implements StudentDAO {
private DataSource dataSource;
private SimpleJdbcCall jdbcCall;
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
this.jdbcCall = new SimpleJdbcCall(dataSource).
withProcedureName("getRecord");
}
public void create(String name, Integer age) {
JdbcTemplate jdbcTemplateObject = new JdbcTemplate(dataSource);
String SQL = "insert into Student (name, age) values (?, ?)";
jdbcTemplateObject.update( SQL, name, age);
System.out.println("Created Record Name = " + name + " Age = " + age);
return;
}
public Student getStudent(Integer id) {
SqlParameterSource in = new MapSqlParameterSource().
addValue("in_id", id);
Map<String, Object> out = jdbcCall.execute(in);
Student student = new Student();
student.setId(id);
student.setName((String) out.get("out_name"));
student.setAge((Integer) out.get("out_age"));
return student;
}
public List<Student> listStudents() {
String SQL = "select * from Student";
List <Student> students = jdbcTemplateObject.query(SQL,new StudentMapper());
return students;
}
}
- 配置文件 Beans.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"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd ">
<!-- Initialization for data source -->
<bean id="dataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/TEST"/>
<property name="username" value="root"/>
<property name="password" value="password"/>
</bean>
<!-- Definition for studentJDBCTemplate bean -->
<bean id="studentJDBCTemplate"
class="com.tutorialspoint.StudentJDBCTemplate">
<property name="dataSource" ref="dataSource" />
</bean>
</beans>
- MainApp.java:
package com.tutorialspoint;
import java.util.List;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.tutorialspoint.StudentJDBCTemplate;
public class MainApp {
public static void main(String[] args) {
ApplicationContext context =
new ClassPathXmlApplicationContext("Beans.xml");
StudentJDBCTemplate studentJDBCTemplate =
(StudentJDBCTemplate)context.getBean("studentJDBCTemplate");
System.out.println("------Records Creation--------" );
studentJDBCTemplate.create("Zara", 11);
studentJDBCTemplate.create("Nuha", 2);
studentJDBCTemplate.create("Ayan", 15);
System.out.println("------Listing Multiple Records--------" );
List<Student> students = studentJDBCTemplate.listStudents();
for (Student record : students) {
System.out.print("ID : " + record.getId() );
System.out.print(", Name : " + record.getName() );
System.out.println(", Age : " + record.getAge());
}
System.out.println("----Listing Record with ID = 2 -----" );
Student student = studentJDBCTemplate.getStudent(2);
System.out.print("ID : " + student.getId() );
System.out.print(", Name : " + student.getName() );
System.out.println(", Age : " + student.getAge());
}
}
- 输出消息:
------Records Creation--------
Created Record Name = Zara Age = 11
Created Record Name = Nuha Age = 2
Created Record Name = Ayan Age = 15
------Listing Multiple Records--------
ID : 1, Name : Zara, Age : 11
ID : 2, Name : Nuha, Age : 2
ID : 3, Name : Ayan, Age : 15
----Listing Record with ID = 2 -----
ID : 2, Name : Nuha, Age : 2
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