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  • Spring中使用JDBC

    首先要获得DataSource连接池:
    要对数据库执行任何的JDBC操作，需要有一个Connection.在Spring中，Connection对象是通过DataSource获得的。

    有几种方法可以得到DataSource, 其中一种方法是使用Spring提供的轻量级org.springframework.jdbc.datasource.DriverManagerDataSource，第二种方法是使用org.apache.commons.dbcp.BasicDataSource类。

    一：使用DriverMangerDataSource，这种方法是轻量级的，方便测试

     1 public class DataSoureProvider {
 2     public static DriverManagerDataSource dataSource = new DriverManagerDataSource();
 3 
 4     public static DriverManagerDataSource getInstance() {
 5         dataSource.setDriverClassName("com.mysql.jdbc.Driver");
 6         dataSource.setUrl("jdbc:mysql://localhost:3306/book");
 7         dataSource.setUsername("y****");
 8         dataSource.setPassword("h*******");
 9         return dataSource;
10     }
11 
12     @Test
13     public void test() {
14         DataSoureProvider.getInstance();
15         try {
16             dataSource.getConnection();
17         }
18         catch (SQLException e) {
19             e.printStackTrace();
20         }
21     }
22 }

    第5~8行是配置连接数据库所需的信息。

    二：使用BasicDataSouce创建一个连接池。应为BasicDataSource所有属性都是通过setter方法暴露在外面的，我们可以像配置其他Srping Bean那样配置它
    我将数据库连接信息配置在properties文件中，利用spring的org.springframeword.beans.factory.config.PropertyPlaceholderConfigurer类进行读取装载，可以查看spring_装配Bean一文。

    书写配置文件applicationContext.xml:

     1 <?xml version="1.0" encoding="UTF-8"?>
 2 <beans
 3     xmlns="http://www.springframework.org/schema/beans"
 4     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 5     xmlns:p="http://www.springframework.org/schema/p"
 6     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
 7 
 8     <bean id="dbproperty" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
 9         <property name="location">
10             <value>connect.properties</value>
11         </property>
12     </bean>
13     
14     <bean id="myDataSource" class="org.apache.commons.dbcp.BasicDataSource">
15         <property name="driverClassName">
16             <value>${db.driver}</value>
17         </property>
18         <property name="url">
19             <value>${db.url}</value>
20         </property>
21         <property name="username">
22             <value>${db.username}</value>
23         </property>
24         <property name="password">
25             <value>${db.password}</value>
26         </property>
27     </bean>
28 </beans>

    第14~27行配置BasicDataSource参数，其中<value>中的参数是在connect.propertices配置文件中拿到的。

    进行测试：

     1 public class DataSourceProvider2 {
 2     @Test
 3     public void connectTest() {
 4         ApplicationContext context = new ClassPathXmlApplicationContext(
 5                 "applicationContext.xml");
 6         BasicDataSource dataSource = (BasicDataSource) context
 7                 .getBean("myDataSource");
 8         try {
 9             dataSource.getConnection();
10             System.out.println("connect successful");
11         }
12         catch (SQLException e) {
13             e.printStackTrace();
14         }
15     }
16     
17 }

    使用org.apache.commons.dbcp.BasicDataSource需要引入额外的jar包，分别是commons-collections-2.1.1.jar,commons-dbcp-1.4.jar,commons-pool-1.2.jar.为了方便大家，这里有这三个jar包的下载地址：http://pan.baidu.com/share/link?shareid=68214&uk=2198762756#dir/path=%2Flib%2Fdatasource

    Spring把JDBC中重复的操作建立成了一个模板类org.springframework.jdbc.core.JdbcTemplate。

     

    使用JdbcTemplate:
    要使用JdbcTemplate,需要为每一个DAO配置一个JdbcTemplate实例

    1 public class StudentDaoImp implements StudentDao {
2     private JdbcTemplate jdbcTemplate;
3 
4     @Override
5     public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
6         this.jdbcTemplate = jdbcTemplate;
7     }
8 }

    如上，StudentDaoImp内配置了一个JdbcTemplate对象和它对应的setter方法。这样就可以在Spring配置文件中对其进行赋值。

     1 <?xml version="1.0" encoding="UTF-8"?>
 2 <beans xmlns="http://www.springframework.org/schema/beans"
 3     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
 4     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
 5 
 6     <bean id="dbproperty"
 7         class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
 8         <property name="location">
 9             <value>connect.properties</value>
10         </property>
11     </bean>
12 
13     <bean id="myDataSource" class="org.apache.commons.dbcp.BasicDataSource">
14         <property name="driverClassName">
15             <value>${db.driver}</value>
16         </property>
17         <property name="url">
18             <value>${db.url}</value>
19         </property>
20         <property name="username">
21             <value>${db.username}</value>
22         </property>
23         <property name="password">
24             <value>${db.password}</value>
25         </property>
26     </bean>
27 
28     <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
29         <property name="dataSource">
30             <ref bean="myDataSource"/>
31         </property>
32     </bean>
33     
34     <bean id="studentDao" class="com.sunflower.dao.StudentDaoImp">
35         <property name="jdbcTemplate">
36             <ref bean="jdbcTemplate"/>
37         </property>
38     </bean>
39 </beans>

    第28~32行是装配JdbcTemplate这个Bean,其中需要为其设置dataSource这个参数，就是我们上面的到的DataSource.

    使用JdbcTemplate插入数据:

     1 public class StudentDaoImp implements StudentDao {
 2     private JdbcTemplate jdbcTemplate;
 3 
 4     @Override
 5     public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
 6         this.jdbcTemplate = jdbcTemplate;
 7     }
 8     
 9     public void insert(Student student)
10     {
11         String sql = "insert into student (cno,name,score) values(?,?,?)";
12         //设置传递给通配符的参数
13         Object[] params = new Object[]{student.getCno(), student.getName(), student.getScore()};
14         jdbcTemplate.update(sql, params);
15     }
16 }

    第9~15行为插入一条学生记录的方法，第14行中，JdbcTemplate为我们提供了update(String sql,Object... args)方法，方便我们进行数据的插入. 

    进行测试：

     1 public class InsertTest {
 2     @Test
 3     public void insertTest() {
 4         Student student = new Student();
 5         student.setCno(1);
 6         student.setName("张飞");
 7         student.setScore(50);
 8 
 9         ApplicationContext context = new ClassPathXmlApplicationContext(
10                 "applicationContext.xml");
11         StudentDaoImp studentDao = (StudentDaoImp) context.getBean("studentDao");
12         studentDao.insert(student);
13     }
14 }

    数据库中多了一条记录：

    mysql> select * from student;
    +-----+-----+------+-------+
    | sno | cno | name | score |
    +-----+-----+------+-------+
    | 1 | 1 | 地心 | 50 |
    | 2 | 2 | 华雄 | 88 |
    | 3 | 1 | 孝慈 | 90 |
    | 4 | 3 | 必须 | 42 |
    | 5 | 1 | 华雄 | 74 |
    | 6 | 2 | 地心 | 75 |
    | 7 | 2 | 横切 | 85 |
    | 11 | 2 | 横切 | 85 |
    | 12 | 2 | 横切 | 85 |
    | 14 | 1 | 张飞 | 50 |
    +-----+-----+------+-------+
    10 rows in set

    批量插入数据：
    批量插入数据需要用到org.springframework.jdbc.core.BatchPreparedStatementSetter接口。

    修改StudentDaoImp:

     1 public class StudentDaoImp implements StudentDao {
 2     private JdbcTemplate jdbcTemplate;
 3 
 4     @Override
 5     public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
 6         this.jdbcTemplate = jdbcTemplate;
 7     }
 8     
 9     public int insert(Student student)
10     {
11         String sql = "insert into student (cno,name,score) values(?,?,?)";
12         //设置传递给通配符的参数
13         Object[] params = new Object[]{student.getCno(), student.getName(), student.getScore()};
14         return jdbcTemplate.update(sql, params);
15     }
16     
17     public int[] batchInsert(final List<Student> list)
18     {
19         String sql = "insert into student (cno,name,score) values(?,?,?)";
20         
21         BatchPreparedStatementSetter setter = new BatchPreparedStatementSetter() {
22             
23             @Override
24             public void setValues(PreparedStatement ps, int index) throws SQLException {
25                 Student student = (Student) list.get(index);
26                 ps.setInt(1, student.getCno());
27                 ps.setString(2, student.getName());
28                 ps.setDouble(3, student.getScore());
29             }
30             
31             //有多少条记录要处理
32             @Override
33             public int getBatchSize() {
34                 return list.size();
35             }
36         };
37         
38         return jdbcTemplate.batchUpdate(sql, setter);
39     }
40 }

    第17~39行为批量插入的方法，BatchPreparedStatementSetter接口的两个方法，其中getBatchSize()方法是得到需要插入的记录的个数，setValues(PreparedStatement ps, int index)方法是实际进行插入的方法。

    进行测试：

     1 @Test
 2     public void batchInsert() {
 3         Student student1 = null, student2 = null, student3 = null;
 4         student1 = new Student();
 5         student2 = new Student();
 6         student3 = new Student();
 7 
 8         student1.setCno(1);
 9         student1.setName("刘备");
10         student1.setScore(70);
11 
12         student2.setCno(2);
13         student2.setName("关羽");
14         student2.setScore(90);
15 
16         student3.setCno(2);
17         student3.setName("张飞");
18         student3.setScore(40);
19 
20         List<Student> list = new ArrayList<Student>();
21         list.add(student1);
22         list.add(student2);
23         list.add(student3);
24 
25         ApplicationContext context = new ClassPathXmlApplicationContext(
26                 "applicationContext.xml");
27         StudentDaoImp studentDao = (StudentDaoImp) context
28                 .getBean("studentDao");
29         studentDao.batchInsert(list);
30     }

    插入结果：
    mysql> select * from student;

    +-----+-----+------+-------+
    | sno | cno | name | score |
    +-----+-----+------+-------+
    | 15 | 1 | 刘备 | 70 |
    | 16 | 2 | 关羽 | 90 |
    | 17 | 2 | 张飞 | 40 |
    +-----+-----+------+-------+
    3 rows in set


    查询一条记录：
    执行一条数据的查询，需要使用org.springframework.jdbc.core.RowCallbackHandler接口的实现。

    修改StudentDaoImp:

     1 /**
 2      * 查询一条记录
 3      */
 4     public Student getStudent(final int id) {
 5         // 装载查询结果
 6         final Student student = new Student();
 7 
 8         String sql = "select s.cno,s.name,s.score from student s where sno = ?";
 9         // 设置查询参数
10         final Object[] params = new Object[] { new Integer(id) };
11         // 进行查询
12         jdbcTemplate.query(sql, params, new RowCallbackHandler() {
13             @Override
14             public void processRow(ResultSet rs) throws SQLException {
15                 student.setCno(rs.getInt("cno"));
16                 student.setName(rs.getString("name"));
17                 student.setScore(rs.getDouble("score"));
18             }
19         });
20         
21         return student;
22     }

    进行测试：

     1 @Test
 2     public void selectTest() {
 3         ApplicationContext context = new ClassPathXmlApplicationContext(
 4                 "applicationContext.xml");
 5         StudentDaoImp studentDao = (StudentDaoImp) context
 6                 .getBean("studentDao");
 7 
 8         Student student = studentDao.getStudent(15);
 9         System.out.println("cno:" + student.getCno() + " name:"+ student.getName() + " score:" + student.getScore());
10     }

    查询多条记录：
    这里需要用到org.springframework.jdbc.core.RowMapper接口的实现。

    修改StudentDaoImp:

     1 /**
 2      * 查询多条记录
 3      */
 4     public List<Student> getAllStudent() {
 5         String sql = "select s.cno,s.name,s.score from student s";
 6 
 7         return jdbcTemplate.query(sql, new RowMapper<Student>() {
 8             @Override
 9             public Student mapRow(ResultSet rs, int index) throws SQLException {
10                 Student student = new Student();
11                 student.setCno(rs.getInt("cno"));
12                 student.setName(rs.getString("name"));
13                 student.setScore(rs.getDouble("score"));
14 
15                 return student;
16             }
17         });
18     }

    RowMapper接口负责把Result中的一条记录映射成一个对象。

    进行测试：

     1 @Test
 2     public void getAllStudent() {
 3         ApplicationContext context = new ClassPathXmlApplicationContext(
 4                 "applicationContext.xml");
 5         StudentDaoImp studentDao = (StudentDaoImp) context
 6                 .getBean("studentDao");
 7 
 8         List<Student> list = new ArrayList<Student>();
 9         list = studentDao.getAllStudent();
10 
11         for (int i = 0; i < list.size(); i++) {
12             System.out.println("name is:" + list.get(i).getName());
13         }
14     }

    也可以使用这种方法查询一条记录，只要附加查询参数即可：

     1 /**
 2      * 查询一条记录
 3      */
 4     public Student getStudent(final int id) {
 5         // 装载查询结果
 6         final Student student = new Student();
 7 
 8         String sql = "select s.cno,s.name,s.score from student s where sno = ?";
 9         // 设置查询参数
10         final Object[] params = new Object[] { new Integer(id) };
11 
12         List<Student> list = jdbcTemplate.query(sql, params,
13                 new RowMapper<Student>() {
14                     @Override
15                     public Student mapRow(ResultSet rs, int index)
16                             throws SQLException {
17                         Student student = new Student();
18                         student.setCno(rs.getInt("cno"));
19                         student.setName(rs.getString("name"));
20                         student.setScore(rs.getDouble("score"));
21 
22                         return student;
23                     }
24                 });
25         
26         return list.get(0);
27     }
    一颗平常心，踏踏实实，平静对待一切
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  • 原文地址：https://www.cnblogs.com/hanyuan/p/2712132.html
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