[无名弟子]JAVA-王振宇|2020年06月01日的日报-技能树.IT修真院

发表于： 2020-06-01 22:02:56

1 609

今日作为：用spring JDBC Template 完成了任务1-17

同时使用spring反转控制来生成类对象

使用@Test来测试

使用String toString(){

}

代码：

实体类：

package com.jnshu.vo;

public class MySql_Values {
        private int id;
        private String name;
        private String school;
        private String online_un;
        private int number;
        private String city;

        public int getId() {
            return id;
        }

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

        public String getName() {
            return name;
        }

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

        public String getSchool() {
            return school;
        }

        public void setSchool(String school) {
            this.school = school;
        }

        public String getOnline_un() {
            return online_un;
        }

        public void setOnline_un(String online_un) {
            this.online_un = online_un;
        }

        public int getNumber() {
            return number;
        }

        public void setNumber(int number) {
            this.number = number;
        }

        public String getCity() {
            return city;
        }

        public void setCity(String city) {
            this.city = city;
        }

        public String toString(){
            return "MySql_Valuse [id = " + id + ", name = " + name + ", school = " + school + ", online_un = "
                                                + online_un + ", number = " + number + ", city = " + city +"]";
        }

}

接口：

package com.jnshu.interfaceDAO;

public interface DAO_interface {
    //标识接口
}

实现类：

package com.jnshu.impl;

import com.jnshu.DataBaseConn.DataBaseConnection;
import com.jnshu.interfaceDAO.DAO_interface;
import com.jnshu.vo.MySql_Values;
import org.junit.Test;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.RowMapper;

import java.util.List;

public class Do_Mysqls implements DAO_interface {

@Test
    public void QueryForObject() {
        //DataBaseConnection conn = new DataBaseConnection();
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");
        DataBaseConnection dataBaseConnection = (DataBaseConnection) context.getBean("dataBaseConnection");
        String sql = "select * from students";
        RowMapper<MySql_Values> rowMapper = new BeanPropertyRowMapper<MySql_Values>(MySql_Values.class);
        List<MySql_Values> users = dataBaseConnection.getJdbcTemplate().query(sql, rowMapper);

        for (MySql_Values students : users){
            System.out.println(students);
        }

    }
}

数据库连接：

package com.jnshu.DataBaseConn;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.JdbcTemplate;

public class DataBaseConnection {

    private  ApplicationContext cxt = new ClassPathXmlApplicationContext("applicationContext.xml");
    private JdbcTemplate jdbcTemplate = (JdbcTemplate) cxt.getBean("jdbcTemplate");

    public JdbcTemplate getJdbcTemplate() {
        return jdbcTemplate;
    }
}

结果：

使用的resouces配置文件:

db.properties.xml：

jdbc.user = root
jdbc.password = 54229103w
jdbc.driverClass = com.mysql.cj.jdbc.Driver
jdbc.jdbcUrl = jdbc:mysql://localhost:3306/it-xzy?serverTimezone=UTC&useUnicode=true&characterEncoding=utf8&useSSL=true

jdbc.initPoolSize = 5
jdbc.maxPoolSize = 10

applivationContext.xml:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd">

    <!-- 导入资源文件
        读取db.properties文件中的数据 -->
    <context:property-placeholder location="classpath:db.properties"/>

    <!-- 配置C3P0数据源 -->
    <bean id="dataSource"
          class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="user" value="${jdbc.user}"></property>
        <property name="password" value="${jdbc.password}"></property>
        <property name="jdbcUrl" value="${jdbc.jdbcUrl}"></property>
        <property name="driverClass" value="${jdbc.driverClass}"></property>

        <property name="initialPoolSize" value="${jdbc.initPoolSize}"></property>
        <property name="maxPoolSize" value="${jdbc.maxPoolSize}"></property>
    </bean>



    <!-- 配置Spring的jdbcTemplate
        并注入一个dataSource数据源-->
    <bean id="jdbcTemplate"
          class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource"></property>
    </bean>
</beans>

spring.xml:(使用spring来生成类对象，反转控制)

<?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.xsd">


    <bean id="dataBaseConnection" class="com.jnshu.DataBaseConn.DataBaseConnection"></bean>
</beans>

顺便附上pom.xml

以便将来的学弟们能直接抄一份，不用一个一个去找了

<?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/maven-v4_0_0.xsd">

  <modelVersion>4.0.0</modelVersion>

  <groupId>com.jnshu</groupId>
  <artifactId>MyTest_Template</artifactId>
  <packaging>jar</packaging>
  <version>1.0-SNAPSHOT</version>

  <name>A Camel Route</name>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
  </properties>

  <dependencyManagement>
    <dependencies>
      <!-- Camel BOM -->
      <dependency>
        <groupId>org.apache.camel</groupId>
        <artifactId>camel-parent</artifactId>
        <version>3.3.0</version>
        <scope>import</scope>
        <type>pom</type>
      </dependency>
    </dependencies>
  </dependencyManagement>

  <dependencies>
    <!-- https://mvnrepository.com/artifact/com.mchange/c3p0 -->
    <dependency>
      <groupId>com.mchange</groupId>
      <artifactId>c3p0</artifactId>
      <version>0.9.5.5</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/com.google.code.maven-play-plugin.com.mchange/c3p0-oracle-thin-extras -->
    <dependency>
      <groupId>com.google.code.maven-play-plugin.com.mchange</groupId>
      <artifactId>c3p0-oracle-thin-extras</artifactId>
      <version>0.9.5</version>
    </dependency>


    <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
      <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.20</version>
      </dependency>

      <!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
      <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jdbc</artifactId>
        <version>5.2.6.RELEASE</version>
      </dependency>

    <!-- https://mvnrepository.com/artifact/org.springframework/spring-test -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-test</artifactId>
      <version>5.2.6.RELEASE</version>
      <scope>test</scope>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.springframework/spring-beans -->
      <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-beans</artifactId>
        <version>5.2.6.RELEASE</version>
      </dependency>

      <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
      <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>5.2.6.RELEASE</version>
      </dependency>

    <!-- https://mvnrepository.com/artifact/org.springframework/spring-core -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-core</artifactId>
      <version>5.2.6.RELEASE</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.springframework/spring-expression -->
      <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-expression</artifactId>
        <version>5.2.6.RELEASE</version>
      </dependency>

    <!-- https://mvnrepository.com/artifact/org.springframework.webflow/spring-binding -->
    <dependency>
      <groupId>org.springframework.webflow</groupId>
      <artifactId>spring-binding</artifactId>
      <version>2.5.1.RELEASE</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.openjfx/javafx-controls -->
    <dependency>
      <groupId>org.openjfx</groupId>
      <artifactId>javafx-controls</artifactId>
      <version>11.0.2</version>
    </dependency>


    <!-- https://mvnrepository.com/artifact/org.springframework/spring-tx -->
      <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-tx</artifactId>
        <version>5.2.6.RELEASE</version>
      </dependency>

    <!-- https://mvnrepository.com/artifact/com.mchange/mchange-commons-java -->
    <dependency>
      <groupId>com.mchange</groupId>
      <artifactId>mchange-commons-java</artifactId>
      <version>0.2.20</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.springframework/spring -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring</artifactId>
      <version>5.2.6.RELEASE</version>
      <type>pom</type>
    </dependency>


      <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.11</version>
      </dependency>

    <dependency>
      <groupId>org.apache.camel</groupId>
      <artifactId>camel-core</artifactId>
    </dependency>
    <dependency>
      <groupId>org.apache.camel</groupId>
      <artifactId>camel-main</artifactId>
    </dependency>

    <!-- logging -->
    <dependency>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-slf4j-impl</artifactId>
      <scope>runtime</scope>
    </dependency>

    <!-- testing -->
    <dependency>
      <groupId>org.apache.camel</groupId>
      <artifactId>camel-test</artifactId>
      <scope>test</scope>
    </dependency>


  </dependencies>

  <build>
    <defaultGoal>install</defaultGoal>

    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.8.1</version>
        <configuration>
          <source>1.8</source>
          <target>1.8</target>
        </configuration>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-resources-plugin</artifactId>
        <version>3.1.0</version>
        <configuration>
          <encoding>UTF-8</encoding>
        </configuration>
      </plugin>

      <!-- Allows the example to be run via 'mvn compile exec:java' -->
      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>exec-maven-plugin</artifactId>
        <version>1.6.0</version>
        <configuration>
          <mainClass>com.jnshu.MainApp</mainClass>
          <includePluginDependencies>false</includePluginDependencies>
        </configuration>
      </plugin>

    </plugins>
  </build>

</project>

明天的计划：用Mybatis完成1-17

今日疑惑：如下图这么写或报错？为什么？

public class DataBaseConnection {

    private  ApplicationContext cxt = null;
    private JdbcTemplate jdbcTemplate;

   
        cxt = new ClassPathXmlApplicationContext("applicationContext.xml");
        jdbcTemplate = (JdbcTemplate) cxt.getBean("jdbcTemplate");
    
    
    public JdbcTemplate getJdbcTemplate() {
        return jdbcTemplate;
    }
}

这么写加上{ }就不会报错

public class DataBaseConnection {

    private  ApplicationContext cxt = null; 
    private JdbcTemplate jdbcTemplate;

    {
        cxt = new ClassPathXmlApplicationContext("applicationContext.xml");
        jdbcTemplate = (JdbcTemplate) cxt.getBean("jdbcTemplate");
    }
    public JdbcTemplate getJdbcTemplate() {
        return jdbcTemplate;
    }
}

或者这么写也不会报错，就第一种会报错？？？？

public class DataBaseConnection {

    private  ApplicationContext cxt = new ClassPathXmlApplicationContext("applicationContext.xml");
    private JdbcTemplate jdbcTemplate = (JdbcTemplate) cxt.getBean("jdbcTemplate");
    
    public JdbcTemplate getJdbcTemplate() {
        return jdbcTemplate;
    }
}

跪求师兄解答一下，这东西百度都还找不着我也是服了？？？？

一万个问号淦

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【任务1】 [无名弟子]JAVA-王振宇 | 2020年06月01日 的日报 上品

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【任务1】 [无名弟子]JAVA-王振宇 | 2020年06月01日的日报上品