Spring JDBC NamedParameterJdbcTemplate類示例

org.springframework.jdbc.core.NamedParameterJdbcTemplate類是一個具有基本JDBC操作的模板類，允許使用命名參數而不是傳統的’?‘占位符。 這個類代表一個包裝的JdbcTemplate，在執行時完成從命名參數占位符替換為JDBC樣式’?‘ 占位符。它還允許將值列表擴展到適當數量的占位符。

使用到的 Student 表的結構如下 -

CREATE TABLE Student( ID INT NOT NULL AUTO_INCREMENT, NAME VARCHAR(20) NOT NULL, AGE INT NOT NULL, DESCRIPTION LONGTEXT DEFAULT NULL, PRIMARY KEY (ID) ); 

SQL

類的聲明

以下是org.springframework.jdbc.core.NamedParameterJdbcTemplate接口的聲明 -

public class NamedParameterJdbcTemplate extends Object implements NamedParameterJdbcOperations 

Java

語法

MapSqlParameterSource in = new MapSqlParameterSource(); in.addValue("id", id); in.addValue("description", new SqlLobValue(description, new DefaultLobHandler()), Types.CLOB); String SQL = "update Student set description = :description where id = :id"; NamedParameterJdbcTemplate jdbcTemplateObject = new NamedParameterJdbcTemplate(dataSource); jdbcTemplateObject.update(SQL, in); 

Java

在上代碼中，

• in - SqlParameterSource對象將參數傳遞給更新查詢。
• SqlLobValue - 表示SQL BLOB/CLOB值參數的對象。
• jdbcTemplateObject - NamedParameterJdbcTemplate對象來更新數據庫中的Student對象。

實例項目

要了解上述與Spring JDBC相關的概念，下面我們編寫一個使用NamedParameterJdbcTemplate來更新Student對象。打開Eclipse IDE，並按照以下步驟創建一個Spring應用程序，這里創建一個名稱為：NamedParameterJdbcTemplate 的項目。

步驟說明

1. 參考第一個Spring JDBC項目來創建一個Maven項目 - http://www.yiibai.com/springjdbc/first_application.html
2. 更新bean配置並運行應用程序。

完整的項目結構如下所示 -

以下是Maven配置文件：pom.xml的代碼內容：

<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.yiibai</groupId> <artifactId>NamedParameterJdbcTemplate</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>NamedParameterJdbcTemplate</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> 

XML

以下是數據訪問對象接口文件：StudentDAO.java的內容：

package com.yiibai; 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(); /** * This is the method to be used to update a record into the Student table. */ public void updateDescription(Integer id, String description); public void create(String name, Integer age); } 

Java

以下是文件：Student.java的代碼內容：

package com.yiibai; public class Student { private Integer age; private String name; private Integer id; private String description; 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; } public String getDescription() { return description; } public void setDescription(String description) { this.description = description; } } 

Java

以下是文件：StudentMapper.java的代碼內容：

package com.yiibai; 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")); student.setDescription(rs.getString("description")); return student; } } 

Java

實現類StudentJDBCTemplate.java實現了定義的DAO接口 - StudentDAO.java，以下是文件：StudentJDBCTemplate.java的代碼內容：

package com.yiibai; import java.util.List; import javax.sql.DataSource; import org.springframework.jdbc.core.JdbcTemplate; import org.springframework.jdbc.core.namedparam.MapSqlParameterSource; import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate; import org.springframework.jdbc.core.namedparam.SqlParameterSource; import org.springframework.jdbc.core.simple.SimpleJdbcCall; import org.springframework.jdbc.core.support.SqlLobValue; import org.springframework.jdbc.support.lob.DefaultLobHandler; import java.io.ByteArrayInputStream; import java.sql.Types; 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, description) values (?, ?, NULL)"; jdbcTemplateObject.update(insertQuery, name, age); System.out.println("Created Record Name = " + name + " Age = " + age); return; } public void updateDescription(Integer id, String description) { MapSqlParameterSource in = new MapSqlParameterSource(); in.addValue("id", id); in.addValue("description", new SqlLobValue(description, new DefaultLobHandler()), Types.CLOB); String SQL = "update Student set description = :description where id = :id"; NamedParameterJdbcTemplate jdbcTemplateObject = new NamedParameterJdbcTemplate(dataSource); jdbcTemplateObject.update(SQL, in); System.out.println("Updated Record with ID = " + id); } } 

Java

以下是文件：MainApp.java的代碼內容：

package com.yiibai; import java.util.ArrayList; import java.util.List; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; import com.yiibai.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); // 更新描述 studentJDBCTemplate.updateDescription(1, "This can be a very long text upto 4 GB of size."); studentJDBCTemplate.updateDescription(2, "隨便寫一下描述內容......易百教程(www.yiibai.com) - 專注於IT教程和實例"); 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(", Description : " + record.getDescription()); } } } 

Java

以下是文件：application-beans.xml的代碼內容：

<?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.yiibai.StudentJDBCTemplate"> <property name="dataSource" ref="dataSource" /> </bean> </beans> 

XML

注意： application-beans.xml 文件的位置是：{workspace}/fistapp/src/main/java 目錄，如果放置錯了，程序可能會因為找不到此配置文件而出錯。

完成創建源代碼和bean和數據庫連接信息的文件配置后，運行應用程序。這里先簡單說明一下運行的步驟，在項目名稱(NamedParameterJdbcTemplate)上點擊右鍵，在彈出的菜單中選擇：【Run As】-> 【Maven test】

在運行測試成功后，應該會輸出類似以下內容(含有 BUILD SUCCESS 的信息) 。
接下來，點擊類文件：MainApp.java 選擇【Run As】->【Java Application】，如果應用程序一切正常，這將打印以下結果：

------Records Creation--------
Created Record Name = Maxsu Age = 21
Created Record Name = Curry Age = 22
Created Record Name = Suzend Age = 23
Updated Record with ID = 1
Updated Record with ID = 2
------Listing Multiple Records--------
ID : 1, Name : Maxsu, Age : 21
, Description : This can be a very long text upto 4 GB of size.
ID : 2, Name : Curry, Age : 22
, Description : 隨便寫一下描述內容......易百教程(www.yiibai.com) - 專注於IT教程和實例
ID : 3, Name : Suzend, Age : 23
, Description : null