JDBC 框架概述
在使用普通的 JDBC 數據庫時,就會很麻煩的寫不必要的代碼來處理異常,打開和關閉數據庫連接等。但 Spring JDBC 框架負責所有的低層細節,從開始打開連接,準備和執行 SQL 語句,處理異常,處理事務,到最後關閉連接。
JdbcTemplate 類
JdbcTemplate 類執行 SQL 查詢、更新語句和存儲過程調用,執行迭代結果集和提取返回參數值。它也捕獲 JDBC 異常並轉換它們到 org.springframework.dao 包中定義的通用類、更多的信息、異常層次結構。JdbcTemplate 類的實例是線程安全配置的。
配置數據源
創建數據庫test,並創建數據表。
CREATE TABLE Student(
ID INT NOT NULL AUTO_INCREMENT,
NAME VARCHAR(20) NOT NULL,
AGE INT NOT NULL,
PRIMARY KEY (ID)
);
1.導入spring 所需包 以及 spring-jdbc 包,創建配置文件 bans.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>
2.創建實體bane類
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;
}
}
3.創建接口,(方法實方法定義,隔絕new)
public interface StudentDAO {
public void setDataSource(DataSource ds);
public void create(String name, Integer age);
public Student getStudent(Integer id);
public List<Student> listStudents();
public void delete(Integer id);
public void update(Integer id, Integer age);
}
4.創建一個Mapper類
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;
}
}
5.創建接口實現類
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;
}
}
6.測試
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());
}
}