SpringBoot使用JdbcTemplate


  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:

  1. execute:可以用於執行任何的SQL語句,一般用於執行DDL語句;
  2. update和batchUpdate:用於執行新增、修改、刪除等語句,batch是批量的意思;
  3. query和queryForObject:用於查詢相關語句;
  4. 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。


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