Spring JDBC PreparedStatementSetter接口示例

org.springframework.jdbc.core.PreparedStatementSetter接口充当JdbcTemplate类使用的一般回调接口。该接口在JdbcTemplate类提供的PreparedStatement上设置了使用相同SQL的批处理中的每个更新的值。实现负责设置必要的参数。已经提供带有占位符的SQL，使用此接口比PreparedStatementCreator更容易：JdbcTemplate将创建PreparedStatement，回调仅负责设置参数值。

接口的声明

以下是org.springframework.jdbc.core.PreparedStatementSetter接口的声明 -

public interface PreparedStatementSetter

用法

步骤1 - 使用配置的数据源创建一个JdbcTemplate对象。
步骤2 - 使用JdbcTemplate对象方法进行数据库操作，同时传递PreparedStatementSetter对象来替换查询中的占位符。

实例

以下示例将演示如何使用JdbcTemplate类和PreparedStatementSetter接口进行读取查询。这里我们将从student表中读取记录。

语法

final String SQL = "select * from Student where id = ? ";
List <Student> students = jdbcTemplateObject.query(SQL, new PreparedStatementSetter() {
   public void setValues(PreparedStatement preparedStatement) throws SQLException {
      preparedStatement.setInt(1, id);
  }
},
new StudentMapper());

在上面示例(语法)代码中 -

• SQL - 选择查询语句来来读取学生记录信息。
• jdbcTemplateObject - StudentJDBCTemplate对象从数据库中读取Student对象。
• PreparedStatementSetter - PreparedStatementSetter对象在查询中设置参数。
• StudentMapper - StudentMapper是一个RowMapper对象，用于将每个获取的记录映射到学生对象。

实例项目

要了解上述与Spring JDBC相关的概念，下面我们编写一个select查询语句的示例。打开Eclipse IDE，并按照以下步骤创建一个Spring应用程序，这里创建一个名称为：PreparedStatementSetter 的项目。

步骤说明

1. 参考第一个Spring JDBC项目来创建一个Maven项目 - http://www.zyiz.net/springjdbc/first_application.html
2. 更新bean配置并运行应用程序。

完整的项目结构如下所示 -

以下是Maven配置文件：pom.xml的代码内容：

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.zyiz</groupId>
    <artifactId>PreparedStatementSetter</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>PreparedStatementSetter</name>
    <url>http://maven.apache.org</url>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.40</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>4.1.0.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>4.1.4.RELEASE</version>
        </dependency>
    </dependencies>
</project>

以下是数据访问对象接口文件：StudentDAO.java的内容：

package com.zyiz;

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 list down all the records from the
     * Student table.
     */
    public List<Student> listStudents();
    public Student getStudent(Integer id);
    public void create(String name, Integer age);

}

以下是文件：Student.java的代码内容：

package com.zyiz;

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;
    }
}

以下是文件：StudentMapper.java的代码内容：

package com.zyiz;

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StudentJDBCTemplate.java实现了定义的DAO接口 - StudentDAO.java，以下是文件：StudentJDBCTemplate.java的代码内容：

package com.zyiz;

import java.sql.PreparedStatement;
import java.util.List;
import javax.sql.DataSource;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.ParameterizedPreparedStatementSetter;
import org.springframework.jdbc.core.PreparedStatementSetter;

import java.sql.SQLException;

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 List<Student> listStudents() {
        String SQL = "select * from Student";
        List<Student> students = jdbcTemplateObject.query(SQL, new StudentMapper());
        return students;
    }

    public void create(String name, Integer age) {
        // TODO Auto-generated method stub
        String insertQuery = "insert into student (name, age) values (?, ?)";

        jdbcTemplateObject.update(insertQuery, name, age);
        System.out.println("Created Record Name = " + name + " Age = " + age);
        return;
    }

    public Student getStudent(final Integer id) {
        final String SQL = "select * from Student where id = ? ";
        List<Student> students = jdbcTemplateObject.query(SQL, new PreparedStatementSetter() {
            public void setValues(PreparedStatement preparedStatement) throws SQLException {
                preparedStatement.setInt(1, id);
            }
        }, new StudentMapper());
        return students.get(0);
    }
}

以下是文件：MainApp.java的代码内容：

package com.zyiz;

import java.util.ArrayList;
import java.util.List;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.zyiz.StudentJDBCTemplate;

public class MainApp {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("application-beans.xml");

        StudentJDBCTemplate studentJDBCTemplate = (StudentJDBCTemplate) context.getBean("studentJDBCTemplate");

        System.out.println("------Records Creation--------");
        studentJDBCTemplate.create("Maxsu", 21);
        studentJDBCTemplate.create("Curry", 22);
        studentJDBCTemplate.create("Suzend", 23);

        System.out.println("------Get Student Info by ID=1 --------");
        Student student = studentJDBCTemplate.getStudent(1);
        System.out.print("ID : " + student.getId());
        System.out.println(", Age : " + student.getAge());

        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());
        }
    }
}

以下是文件：application-beans.xml的代码内容：

<?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?characterEncoding=utf8&useSSL=true" />
        <property name="username" value="root" />
        <property name="password" value="123456" />
    </bean>

    <!-- Definition for studentJDBCTemplate bean -->
    <bean id="studentJDBCTemplate" class="com.zyiz.StudentJDBCTemplate">
        <property name="dataSource" ref="dataSource" />
    </bean>

</beans>

注意： application-beans.xml 文件的位置是：{workspace}/fistapp/src/main/java 目录，如果放置错了，程序可能会因为找不到此配置文件而出错。

完成创建源代码和bean和数据库连接信息的文件配置后，运行应用程序。这里先简单说明一下运行的步骤，在项目名称(PreparedStatementSetter)上点击右键，在弹出的菜单中选择：【Run As】-> 【Maven test】

在运行测试成功后，应该会输出类似以下内容(含有 BUILD SUCCESS 的信息) 。
接下来，点击类文件：MainApp.java 选择【Run As】->【Java Application】，如果应用程序一切正常，这将打印以下结果：

------Records Creation--------
Created Record Name = Maxsu Age = 21
Created Record Name = Curry Age = 22
Created Record Name = Suzend Age = 23
------Get Student Info by ID=1 --------
ID : 1, Age : 21
------Listing Multiple Records--------
ID : 1, Name : Maxsu, Age : 21
ID : 2, Name : Curry, Age : 22
ID : 3, Name : Suzend, Age : 23