JdbcTemplate的設計目的是為不同類型的HJDBC操作提供模板方法,每個模板方法都能控制整個數據訪問的過程。
常用方法:
- execute:可以用於執行任何的SQL語句,一般用於執行DDL語句;
- update和batchUpdate:用於執行新增、修改、刪除等語句,batch是批量的意思;
- query和queryForObject:用於查詢相關語句;
- call:用於執行存儲過程、函數等語句。
JdbcTemplate對應的配置信息如下:
<!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-jdbc -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
完整的pom配置如下:
<?xml version="1.0" encoding="UTF-8"?>
<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.cjs</groupId>
<artifactId>springjdbctemplatetest</artifactId>
<version>1.0-SNAPSHOT</version>
<name>springjdbctemplatetest</name>
<!-- FIXME change it to the project's website -->
<url>http://www.example.com</url>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.6.RELEASE</version>
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.7</maven.compiler.source>
<maven.compiler.target>1.7</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<!-- Web依賴 -->
<!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- Mysql依賴 -->
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<!-- JDBC依賴 -->
<!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-jdbc -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
</dependencies>
<build>
<pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
<plugins>
<plugin>
<artifactId>maven-clean-plugin</artifactId>
<version>3.0.0</version>
</plugin>
<!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
<plugin>
<artifactId>maven-resources-plugin</artifactId>
<version>3.0.2</version>
</plugin>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.7.0</version>
</plugin>
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.20.1</version>
</plugin>
<plugin>
<artifactId>maven-jar-plugin</artifactId>
<version>3.0.2</version>
</plugin>
<plugin>
<artifactId>maven-install-plugin</artifactId>
<version>2.5.2</version>
</plugin>
<plugin>
<artifactId>maven-deploy-plugin</artifactId>
<version>2.8.2</version>
</plugin>
</plugins>
</pluginManagement>
</build>
</project>
省略application.properties和Bean類的創建,直接給出XXXDaoImpl類,
package com.cjs.dao.impl; import com.cjs.bean.User; import com.cjs.dao.UserDao; import com.mysql.jdbc.Statement; import org.springframework.jdbc.core.BeanPropertyRowMapper; import org.springframework.jdbc.core.JdbcTemplate; import org.springframework.jdbc.core.PreparedStatementCreator; import org.springframework.jdbc.core.RowMapper; import org.springframework.jdbc.support.GeneratedKeyHolder; import org.springframework.jdbc.support.KeyHolder; import org.springframework.stereotype.Repository; import javax.annotation.Resource; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.SQLException; import java.util.List; @Repository public class UserDaoImpl implements UserDao { @Resource private JdbcTemplate jdbcTemplate;//注入Jdbc模板核心對象
@Override public int insertUser() { String sql = "insert into tb_users(loginname, username, password)"
+ " values(?,?,?),(?,?,?),(?,?,?)"; Object[] args = new Object[]{"swk","Tom", "123456","zbj", "Jean","123456","ts","Jimmy","123456"}; return jdbcTemplate.update(sql, args);//update(String sql, Object[] obj{}),第一個參數時sql語句,第二個參數是填充sql語句的?參數,依次填入 } @Override public User selectByUserName(String username) { String sql = "select * from tb_users where username = ?"; RowMapper<User> rowMapper = new BeanPropertyRowMapper<>(User.class);//設置返回數據類型 User user = jdbcTemplate.queryForObject(sql, new Object[]{username}, rowMapper); return user; } @Override public User selectUserById(int id) { String sql = "select * from tb_users where id = ?"; RowMapper<User> rowMapper = new BeanPropertyRowMapper<>(User.class); User user = jdbcTemplate.queryForObject(sql, new Object[]{id}, rowMapper); return user; } @Override public List<User> findAll() { String sql = "select * from tb_users"; RowMapper<User> rowMapper = new BeanPropertyRowMapper<>(User.class); return jdbcTemplate.query(sql, rowMapper); } @Override public void delete(Integer id) { String sql = "delete from tb_users where id=?"; jdbcTemplate.update(sql, new Object[]{id}); } @Override public void update(User user) { String sql = "update tb_users set username=?, loginname=? where id=?"; jdbcTemplate.update(sql, new Object[]{user.getUsername(), user.getLoginname(), user.getId()}); } @Override public User insertGetKey(final User user) {//獲取新插入數據的id KeyHolder holder = new GeneratedKeyHolder(); jdbcTemplate.update(new PreparedStatementCreator() { @Override public PreparedStatement createPreparedStatement(Connection connection) throws SQLException { String sql = "insert into tb_users(username, loginname, password) values(?,?,?)"; PreparedStatement ps = connection.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS); ps.setString(1,user.getUsername()); ps.setString(2,user.getLoginname()); ps.setString(3,user.getPassword()); return ps; } }, holder); int newUserId = holder.getKey().intValue(); user.setId(newUserId); return user; } }
Biz層和Controller也不是這里重點,上面已經將JdbcTemplate的使用說清楚了,因為文中所說那幾個常用的方法有很多重載,有些人喜歡用三個參數的,xxx(String sql, Object[] obj, RowMapper<T> rm);不管需不需要填充sql語句參數,都寫上,看個人習慣而已。