springboot成神之——spring jdbc的使用

• 本文介绍spring jdbc的使用
  • 目录结构
  • pom配置
  • properties配置
  • model层User类
  • Dao层QueryForListDao
  • config层AppConfiguration
  • 程序入口DemoApplication

本文介绍spring jdbc的使用

目录结构

pom配置

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
	<groupId>mysql</groupId>
	<artifactId>mysql-connector-java</artifactId>
	<scope>runtime</scope>
</dependency>

properties配置

spring.datasource.url=jdbc:mysql://localhost:3306/mydb?useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull&allowMultiQueries=true&useSSL=false&allowPublicKeyRetrieval=true
spring.datasource.username=root
spring.datasource.password=123
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

server.tomcat.uri-encoding=UTF-8
server.port=8888

model层User类

package com.springlearn.learn.model;

public class User{
    private Integer id;
    private String name;
    private Integer age;
    private String sex;

    public User(Integer id, String name, Integer age, String sex) {
        this.id = id;
        this.name = name;
        this.age = age;
        this.sex = sex;
    }

    public Integer getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public Integer getAge() {
        return age;
    }

    public String getSex() {
        return sex;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

}

Dao层QueryForListDao

        /**
         * 第一种用法
         *      List<String> list = this.getJdbcTemplate().queryForList(sql, String.class)
         *
         * 第二种用法
         *      List<Map<String, Object>> list = this.getJdbcTemplate().queryForList(sql);
         *      for (Map<String, Object> item : users) {
         *          System.out.println("UserName: " + item.get("name") + "Age: " + item.get("age") + "Sex: " + item.get("sex"));
         *      }
         *
         * 第三种用法
         *      SqlRowSet rowset = this.getJdbcTemplate().queryForRowSet(sql, new Object[]{3},new int[]{Types.INTEGER});
         *
         *      SqlRowSet rowset = listdao.getUsersList();
         *      while(rowset.next()) {
         *          System.out.println("UserName: " + rowset.getString("name") + "Age: " + rowset.getInt("age") + "Sex: " + rowset.getString("sex"));
         *      }
         *
         * 第四种方式
         *      rowmapper的使用，在我的文章 https://www.cnblogs.com/ye-hcj/p/9618588.html#mapper%E5%B1%82 已经讲过
         *
         * 第五种方式
         *      String sql = "select * from test where id=?;";
         *
         *      RowCallbackHandler handler = new RowCallbackHandler(){
         *
         *          @Override
         *          public void processRow(ResultSet rs) throws SQLException {
         *              System.out.println("id：" + rs.getInt("id") + "UserName: " + rs.getString("name") + "Age: " + rs.getInt("age") + "Sex: " + rs.getString("sex"));
         *          }
         *      };
         *
         *      this.getJdbcTemplate().query(sql, handler, 3);
         *
         *      listdao.getUsersList();
         *
         * 第六种方式，如下
         *
         * 第七中方式，queryForObject 用法和上面类似
         */

package com.springlearn.learn.Dao;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import javax.sql.DataSource;

import com.springlearn.learn.model.User;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.ResultSetExtractor;
import org.springframework.jdbc.core.RowCallbackHandler;
import org.springframework.jdbc.core.support.JdbcDaoSupport;
import org.springframework.jdbc.support.rowset.SqlRowSet;
import org.springframework.stereotype.Repository;

@Repository
public class QueryForListDao extends JdbcDaoSupport{

    @Autowired
    public QueryForListDao(DataSource dataSource) {
        this.setDataSource(dataSource);
    }

    class ListResultSetExtractor implements ResultSetExtractor<List<User>>{

        @Override
        public List<User> extractData(ResultSet rs) throws SQLException, DataAccessException {
            List<User> list = new ArrayList<User>();
            while(rs.next()) {
                list.add(new User(rs.getInt("id"), rs.getString("name"), rs.getInt("age"), rs.getString("sex")));
            }
            return list;
        }
    }

    public List<User> getUsersList() {
        String sql = "select * from test where id=?;";
        ListResultSetExtractor ls = new ListResultSetExtractor();
        List<User> list = this.getJdbcTemplate().query(sql, ls, 2);
        return list;
    }
}

config层AppConfiguration

package com.springlearn.learn.config;

import javax.annotation.Resource;
import javax.sql.DataSource;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.EnvironmentAware;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.context.annotation.PropertySource;
import org.springframework.core.env.Environment;
import org.springframework.jdbc.datasource.DriverManagerDataSource;

@Configuration
@ComponentScan(basePackages = "com.springlearn.learn.*")
@PropertySource("classpath:application.properties")
public class AppConfiguration{
    @Autowired
    private Environment env;

    @Primary
    @Bean(name="dataSource")
    public DataSource dataSource() {
        DriverManagerDataSource dataSource = new DriverManagerDataSource();
        dataSource.setDriverClassName(env.getProperty("spring.datasource.driver-class-name"));
        dataSource.setUrl(env.getProperty("spring.datasource.url"));
        dataSource.setUsername(env.getProperty("spring.datasource.username"));
        dataSource.setPassword(env.getProperty("spring.datasource.password"));

        return dataSource;
    }
}

程序入口DemoApplication

package com.springlearn.learn;

import java.util.List;
import java.util.Map;

import com.springlearn.learn.Dao.QueryForListDao;
import com.springlearn.learn.config.AppConfiguration;
import com.springlearn.learn.model.User;

import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.jdbc.support.rowset.SqlRowSet;

public class DemoApplication {

	public static void main(String[] args) {
		ApplicationContext context = new AnnotationConfigApplicationContext(AppConfiguration.class);
        QueryForListDao listdao = (QueryForListDao)context.getBean(QueryForListDao.class);
        List<User> list = listdao.getUsersList();

        for (User user : list) {
            System.out.println("id：" + user.getId()+ "UserName: " + user.getName() + "Age: " + user.getAge() + "Sex: " + user.getSex());
        }
	}
}