Spring学习五（JDBC支持）

Spring的jdbc支持

1配置db.properties,将有关JDBC的信息载入

2bean文件配置数据源，这里用e3p0作为数据源载入db.properties

3配置template的bean 之后，可以直接使用。

JUnit的测试

代码如下

db.proeprties

jdbc.username=root
jdbc.password=s1127736971
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://127.0.0.1:3306/school
jdbc.iniPoolSize=5
jdbc.maxPoolSize=10
//强烈注意！！！！！ 每行空格也要删掉，因为载入的时候会读取空格

bean文件如下

<?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-4.1.xsd">

<!-- 配置配置文件 -->
<context:property-placeholder location="classpath:db.properties"/>

<!-- 配置数据源文件 -->
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="user" value="${jdbc.username}"></property>
<property name="password" value="${jdbc.password}"></property>
<property name="jdbcUrl" value="${jdbc.url}"></property>
<property name="driverClass" value="${jdbc.driver}"></property>
<property name="initialPoolSize" value="${jdbc.iniPoolSize}"></property>
<property name="maxPoolSize" value="${jdbc.maxPoolSize}"></property>
</bean>

<!-- 配置template -->
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource" ref="dataSource"></property>
</bean>

<context:component-scan base-package="Test"></context:component-scan>
</beans>

java文件如下

package Test;

import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

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;

public class test {
    private ApplicationContext ctx= null;
    private JdbcTemplate jdbcTemplate=null;
    private StudentDao dao;
    {
    ctx=new ClassPathXmlApplicationContext("SpringJDBC.xml");
    jdbcTemplate=(JdbcTemplate) ctx.getBean("jdbcTemplate");//里面就已经配置了datasource的配置，所以可以更改。
    dao=ctx.getBean(StudentDao.class);
    }

    @Test
    public void testStudentDao(){
        System.out.println(dao.getById(2));
    }

    @Test
    public void testQueryForObject(){//用于数据统计类型
        String sql = "SELECT COUNT(id) FROM student ";
        long count = jdbcTemplate.queryForObject(sql, Long.class);
        System.out.println(count);

    }

   @Test
    public void testQueryForList(){//收集属性集合类型
        String sql = "SELECT id,name,age,address FROM student WHERE id>? ";
        RowMapper<Student> rowMapper= new BeanPropertyRowMapper<Student>(Student.class);
        List<Student> students =jdbcTemplate.query(sql, rowMapper,1);//一个不同的集合语句
        System.out.println(students);

    }

    /*
     * 这里要用BeanPropertyRowMapper，不要在queryForObject里面用另一个，格式如下。
     * 1 可以在里面配置类对应的名字，比如 name name 前一个是类属性名字，后一个是database里面名字
     * 2 不支持级联属性
     * 3 RowMapper 是映射属性行，BeanPropertyRowMapper是其一个实现类
     * */
    @Test
    public void testQueryById(){
        String sql = "SELECT id,name,age,address FROM student WHERE id=? ";
        RowMapper<Student> rowMapper= new BeanPropertyRowMapper<Student>(Student.class);
        Student student =jdbcTemplate.queryForObject(sql, rowMapper,1);
        System.out.println(student);
    }

    @Test
    public void testUpdateBatch(){
        String sql = "INSERT INTO student(id,name,age,address) Values(?,?,?,?)";
        List<Object[]> date = new ArrayList<>();
        date.add(new Object[]{"5","xiaohong","52","shanghai"});
        date.add(new Object[]{"6","xiaobai","22","fujian"});
        jdbcTemplate.batchUpdate(sql, date);

    }

    @Test//这个更新可以是 UPDATE DELETE INSERT
    public void testUpdate (){
        String sql = "UPDATE student SET Address = ? where id=?";
        jdbcTemplate.update(sql, "beijing",4);
    }

    @Test
    public void testDataSource() throws SQLException {//测试 DataSource是否可行
       DataSource datasource = (DataSource) ctx.getBean(javax.sql.DataSource.class);//记一个非常不科学的错误，db.properties里面不要有空格，他会把空格也当成命令。
       System.out.println(datasource.getConnection());
    }

}

注，一般用Dao类文件，是将Dao里面添加jdbcTemplate成员属性。而不用另一种extends 的方法，不考虑。

package Test;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.stereotype.Repository;

@Repository//自动装配
public class StudentDao {

    @Autowired
     private JdbcTemplate jdbcTemplate;

    public Student getById(int id){
        String sql = "SELECT id,name,age,address FROM student WHERE id=? ";
        RowMapper<Student> rowMapper= new BeanPropertyRowMapper<Student>(Student.class);
        Student student =jdbcTemplate.queryForObject(sql, rowMapper,id);
        return student;
    }
}

使用jdbc的具名参数设置

配置NamedParameterJdbcTemplate   Bean文件

xml添加

<!-- 配置带参template -->
<bean id="namedtemplate" class="org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate">
<constructor-arg ref="dataSource"></constructor-arg>
</bean>

java代码添加测试

@Test//这是利用对象来具名参数，要求Values(:id,:name,:age,:address)和类的名字要一样，mysql的名字要一样。
    public void testNamedTemplate2(){
        String sql = "INSERT INTO student(id,name,age,address) Values(:id,:name,:age,:address)";
        Student student = new Student();
        student.setId(11);
        student.setAge(4);
        student.setName("xiaoxiaobai");
        student.setAddress("hong shang lu ");
        SqlParameterSource ss = new BeanPropertySqlParameterSource(student);
        namedParameterJdbcTemplate.update(sql, ss);
    }

    @Test//利用具名参数来构造template 优点当参数多的时候维护比较容易 不需要按照固定顺序。缺点是相对于estUpdateBatch()比较复杂
    public void testNamedTemplate(){
        String sql = "INSERT INTO student(id,name,age,address) Values(:id,:name,:age,:address)";
        Map<String,Object> paramMap = new HashMap<String,Object>();
        paramMap.put("id", 10);
        paramMap.put("name", "xiaobai");
        paramMap.put("age",51 );
        paramMap.put("address", "tongbei");
        namedParameterJdbcTemplate.update(sql, paramMap);
        }