Redis在Java中的使用及連線資料庫（附原始碼）

引言：

本文主要分享了Redis如何在IDEA中部署，執行；模擬加入Redis的操作；

1. 在IDEA中搭建Redis

1.1 建立專案

新建含有web的SpringBoot專案；

搭建專案參考：SpringBoot超詳細筆記：https://blog.csdn.net/weixin_42601136/article/details/108396511

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1.2 新增依賴（不夠手動新增）

<dependencies>
    <!--    1、 Jedis-->
    <dependency>
        <groupId>redis.clients</groupId>
        <artifactId>jedis</artifactId>
        <version>2.9.0</version>
    </dependency>
    <!--    2、 Junit測試-->
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jdbc</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-thymeleaf</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>2.1.2</version>
    </dependency>

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

1.3 測試環境是否搭建成功

 @Test
    public void test0() {
        //連線Redis
        Jedis jedis = new Jedis("127.0.0.1", 6379);
        //獲取kak
        String kaka = jedis.get("kak");
        log.info(kaka);
        //建立datex
        String datex = jedis.set("datex", new Date().toString());
        //獲取datex
        String datex1 = jedis.get("datex");
        log.info(datex1);
        //關閉資源
        jedis.close();
    }

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1.4 利用json儲存資料

@Test
    public void test1() {
        JedisPool pool = new JedisPool("127.0.0.1", 6379);
        Jedis jedis = pool.getResource();
        Student student = new Student(1001, "kak", "man", "20");
        String key = "student";
        String field = "1001";
        String s = JsonUtils.objectToJson(student);
        String value = s;
        jedis.hset(key, field, value);
        String hget = jedis.hget(key, field);
        log.info(hget);
        jedis.close();
    }

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1.5 以byte的形式儲存物件

@Test
    public void test02() {
        //連線redis
        Jedis jedis = new Jedis("127.0.0.1", 6379);
        String key = "Student";
        Student value = new Student(1002, "taotao", "woman", "20");
        //將key和value轉換為byte[]
        byte[] byteKey = SerializationUtils.serialize(key);
        byte[] byteValue = SerializationUtils.serialize(value);
        //將key和value儲存到redis中
        jedis.set(byteKey, byteValue);
        //獲取value值
        byte[] bytes = jedis.get(byteKey);
        //bytes反序列化為Student物件
        Student stu = (Student) SerializationUtils.deserialize(bytes);
        System.out.println(stu);
        jedis.close();

    }

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1.6 加入連線池的操作

使用連線池操作，可以避免頻繁的建立和銷燬連線物件的消耗資源

 @Test
    public void test3(){
        //建立連線池
        GenericObjectPoolConfig poolConfig = new GenericObjectPoolConfig();
        poolConfig.setMaxTotal(100);//連線池中的最大活躍數
        poolConfig.setMaxIdle(10);//最大空閒數
        poolConfig.setMinIdle(5);//最小空閒數
        poolConfig.setMaxWaitMillis(3000);//連線池空了，3000毫秒後沒有獲取Jedis物件，超時
        //建立連線池
        JedisPool pool = new JedisPool(poolConfig,"127.0.0.1",6379);
        //通過連線池獲取Jedis物件
        Jedis resource = pool.getResource();
        //獲取上面新增的datex
        String value = resource.get("datex");
        log.info(value);

        resource.close();
    }

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1.7 管道操作

Redis的管道操作，執行一個命令需要先傳送請求到Redis，需要經歷網路延遲，Redis還需給使用者端一個響應；如果需要一次操作多個命令，可以通過管道，將命令放到使用者端的一個Pipeline中，之後一次將命令傳送到伺服器端，伺服器端一次性返回到使用者端；

 @Test
    public void test04(){
        //建立連線池
        JedisPool pool = new JedisPool("127.0.0.1", 6379);
        long l = System.currentTimeMillis();
        //獲取連線物件
        Jedis jedis = pool.getResource();
        //建立管道
        Pipeline pipelined = jedis.pipelined();
        //建立執行kk100000次放入管道中
        for(int i=0;i<100000;i++){
            pipelined.incr("kk");
        }
        //執行命令
        pipelined.syncAndReturnAll();
        jedis.close();

        System.out.print(System.currentTimeMillis() -1);
    }

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2. 從資料中查詢資料

場景：

將資料存入Redis中，避免存取量過大，造成資料庫奔潰；

2.1 生成實體類

package com.sx.kak.po;

import com.sun.xml.internal.ws.developer.Serialization;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.springframework.util.SerializationUtils;

import java.io.Serializable;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Student implements Serializable {
    private Integer id;

    private String name;

    private String sex;

    private String age;

    public Integer getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name == null ? null : name.trim();
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex == null ? null : sex.trim();
    }

    public String getAge() {
        return age;
    }

    public void setAge(String age) {
        this.age = age == null ? null : age.trim();
    }
}

2.2 生成實體模板類

package com.sx.kak.po;

import java.util.ArrayList;
import java.util.List;

public class StudentExample {
    protected String orderByClause;

    protected boolean distinct;

    protected List<Criteria> oredCriteria;

    public StudentExample() {
        oredCriteria = new ArrayList<Criteria>();
    }

    public void setOrderByClause(String orderByClause) {
        this.orderByClause = orderByClause;
    }

    public String getOrderByClause() {
        return orderByClause;
    }

    public void setDistinct(boolean distinct) {
        this.distinct = distinct;
    }

    public boolean isDistinct() {
        return distinct;
    }

    public List<Criteria> getOredCriteria() {
        return oredCriteria;
    }

    public void or(Criteria criteria) {
        oredCriteria.add(criteria);
    }

    public Criteria or() {
        Criteria criteria = createCriteriaInternal();
        oredCriteria.add(criteria);
        return criteria;
    }

    public Criteria createCriteria() {
        Criteria criteria = createCriteriaInternal();
        if (oredCriteria.size() == 0) {
            oredCriteria.add(criteria);
        }
        return criteria;
    }

    protected Criteria createCriteriaInternal() {
        Criteria criteria = new Criteria();
        return criteria;
    }

    public void clear() {
        oredCriteria.clear();
        orderByClause = null;
        distinct = false;
    }

    protected abstract static class GeneratedCriteria {
        protected List<Criterion> criteria;

        protected GeneratedCriteria() {
            super();
            criteria = new ArrayList<Criterion>();
        }

        public boolean isValid() {
            return criteria.size() > 0;
        }

        public List<Criterion> getAllCriteria() {
            return criteria;
        }

        public List<Criterion> getCriteria() {
            return criteria;
        }

        protected void addCriterion(String condition) {
            if (condition == null) {
                throw new RuntimeException("Value for condition cannot be null");
            }
            criteria.add(new Criterion(condition));
        }

        protected void addCriterion(String condition, Object value, String property) {
            if (value == null) {
                throw new RuntimeException("Value for " + property + " cannot be null");
            }
            criteria.add(new Criterion(condition, value));
        }

        protected void addCriterion(String condition, Object value1, Object value2, String property) {
            if (value1 == null || value2 == null) {
                throw new RuntimeException("Between values for " + property + " cannot be null");
            }
            criteria.add(new Criterion(condition, value1, value2));
        }

        public Criteria andIdIsNull() {
            addCriterion("id is null");
            return (Criteria) this;
        }

        public Criteria andIdIsNotNull() {
            addCriterion("id is not null");
            return (Criteria) this;
        }

        public Criteria andIdEqualTo(Integer value) {
            addCriterion("id =", value, "id");
            return (Criteria) this;
        }

        public Criteria andIdNotEqualTo(Integer value) {
            addCriterion("id <>", value, "id");
            return (Criteria) this;
        }

        public Criteria andIdGreaterThan(Integer value) {
            addCriterion("id >", value, "id");
            return (Criteria) this;
        }

        public Criteria andIdGreaterThanOrEqualTo(Integer value) {
            addCriterion("id >=", value, "id");
            return (Criteria) this;
        }

        public Criteria andIdLessThan(Integer value) {
            addCriterion("id <", value, "id");
            return (Criteria) this;
        }

        public Criteria andIdLessThanOrEqualTo(Integer value) {
            addCriterion("id <=", value, "id");
            return (Criteria) this;
        }

        public Criteria andIdIn(List<Integer> values) {
            addCriterion("id in", values, "id");
            return (Criteria) this;
        }

        public Criteria andIdNotIn(List<Integer> values) {
            addCriterion("id not in", values, "id");
            return (Criteria) this;
        }

        public Criteria andIdBetween(Integer value1, Integer value2) {
            addCriterion("id between", value1, value2, "id");
            return (Criteria) this;
        }

        public Criteria andIdNotBetween(Integer value1, Integer value2) {
            addCriterion("id not between", value1, value2, "id");
            return (Criteria) this;
        }

        public Criteria andNameIsNull() {
            addCriterion("NAME is null");
            return (Criteria) this;
        }

        public Criteria andNameIsNotNull() {
            addCriterion("NAME is not null");
            return (Criteria) this;
        }

        public Criteria andNameEqualTo(String value) {
            addCriterion("NAME =", value, "name");
            return (Criteria) this;
        }

        public Criteria andNameNotEqualTo(String value) {
            addCriterion("NAME <>", value, "name");
            return (Criteria) this;
        }

        public Criteria andNameGreaterThan(String value) {
            addCriterion("NAME >", value, "name");
            return (Criteria) this;
        }

        public Criteria andNameGreaterThanOrEqualTo(String value) {
            addCriterion("NAME >=", value, "name");
            return (Criteria) this;
        }

        public Criteria andNameLessThan(String value) {
            addCriterion("NAME <", value, "name");
            return (Criteria) this;
        }

        public Criteria andNameLessThanOrEqualTo(String value) {
            addCriterion("NAME <=", value, "name");
            return (Criteria) this;
        }

        public Criteria andNameLike(String value) {
            addCriterion("NAME like", value, "name");
            return (Criteria) this;
        }

        public Criteria andNameNotLike(String value) {
            addCriterion("NAME not like", value, "name");
            return (Criteria) this;
        }

        public Criteria andNameIn(List<String> values) {
            addCriterion("NAME in", values, "name");
            return (Criteria) this;
        }

        public Criteria andNameNotIn(List<String> values) {
            addCriterion("NAME not in", values, "name");
            return (Criteria) this;
        }

        public Criteria andNameBetween(String value1, String value2) {
            addCriterion("NAME between", value1, value2, "name");
            return (Criteria) this;
        }

        public Criteria andNameNotBetween(String value1, String value2) {
            addCriterion("NAME not between", value1, value2, "name");
            return (Criteria) this;
        }

        public Criteria andSexIsNull() {
            addCriterion("sex is null");
            return (Criteria) this;
        }

        public Criteria andSexIsNotNull() {
            addCriterion("sex is not null");
            return (Criteria) this;
        }

        public Criteria andSexEqualTo(String value) {
            addCriterion("sex =", value, "sex");
            return (Criteria) this;
        }

        public Criteria andSexNotEqualTo(String value) {
            addCriterion("sex <>", value, "sex");
            return (Criteria) this;
        }

        public Criteria andSexGreaterThan(String value) {
            addCriterion("sex >", value, "sex");
            return (Criteria) this;
        }

        public Criteria andSexGreaterThanOrEqualTo(String value) {
            addCriterion("sex >=", value, "sex");
            return (Criteria) this;
        }

        public Criteria andSexLessThan(String value) {
            addCriterion("sex <", value, "sex");
            return (Criteria) this;
        }

        public Criteria andSexLessThanOrEqualTo(String value) {
            addCriterion("sex <=", value, "sex");
            return (Criteria) this;
        }

        public Criteria andSexLike(String value) {
            addCriterion("sex like", value, "sex");
            return (Criteria) this;
        }

        public Criteria andSexNotLike(String value) {
            addCriterion("sex not like", value, "sex");
            return (Criteria) this;
        }

        public Criteria andSexIn(List<String> values) {
            addCriterion("sex in", values, "sex");
            return (Criteria) this;
        }

        public Criteria andSexNotIn(List<String> values) {
            addCriterion("sex not in", values, "sex");
            return (Criteria) this;
        }

        public Criteria andSexBetween(String value1, String value2) {
            addCriterion("sex between", value1, value2, "sex");
            return (Criteria) this;
        }

        public Criteria andSexNotBetween(String value1, String value2) {
            addCriterion("sex not between", value1, value2, "sex");
            return (Criteria) this;
        }

        public Criteria andAgeIsNull() {
            addCriterion("age is null");
            return (Criteria) this;
        }

        public Criteria andAgeIsNotNull() {
            addCriterion("age is not null");
            return (Criteria) this;
        }

        public Criteria andAgeEqualTo(String value) {
            addCriterion("age =", value, "age");
            return (Criteria) this;
        }

        public Criteria andAgeNotEqualTo(String value) {
            addCriterion("age <>", value, "age");
            return (Criteria) this;
        }

        public Criteria andAgeGreaterThan(String value) {
            addCriterion("age >", value, "age");
            return (Criteria) this;
        }

        public Criteria andAgeGreaterThanOrEqualTo(String value) {
            addCriterion("age >=", value, "age");
            return (Criteria) this;
        }

        public Criteria andAgeLessThan(String value) {
            addCriterion("age <", value, "age");
            return (Criteria) this;
        }

        public Criteria andAgeLessThanOrEqualTo(String value) {
            addCriterion("age <=", value, "age");
            return (Criteria) this;
        }

        public Criteria andAgeLike(String value) {
            addCriterion("age like", value, "age");
            return (Criteria) this;
        }

        public Criteria andAgeNotLike(String value) {
            addCriterion("age not like", value, "age");
            return (Criteria) this;
        }

        public Criteria andAgeIn(List<String> values) {
            addCriterion("age in", values, "age");
            return (Criteria) this;
        }

        public Criteria andAgeNotIn(List<String> values) {
            addCriterion("age not in", values, "age");
            return (Criteria) this;
        }

        public Criteria andAgeBetween(String value1, String value2) {
            addCriterion("age between", value1, value2, "age");
            return (Criteria) this;
        }

        public Criteria andAgeNotBetween(String value1, String value2) {
            addCriterion("age not between", value1, value2, "age");
            return (Criteria) this;
        }
    }

    public static class Criteria extends GeneratedCriteria {

        protected Criteria() {
            super();
        }
    }

    public static class Criterion {
        private String condition;

        private Object value;

        private Object secondValue;

        private boolean noValue;

        private boolean singleValue;

        private boolean betweenValue;

        private boolean listValue;

        private String typeHandler;

        public String getCondition() {
            return condition;
        }

        public Object getValue() {
            return value;
        }

        public Object getSecondValue() {
            return secondValue;
        }

        public boolean isNoValue() {
            return noValue;
        }

        public boolean isSingleValue() {
            return singleValue;
        }

        public boolean isBetweenValue() {
            return betweenValue;
        }

        public boolean isListValue() {
            return listValue;
        }

        public String getTypeHandler() {
            return typeHandler;
        }

        protected Criterion(String condition) {
            super();
            this.condition = condition;
            this.typeHandler = null;
            this.noValue = true;
        }

        protected Criterion(String condition, Object value, String typeHandler) {
            super();
            this.condition = condition;
            this.value = value;
            this.typeHandler = typeHandler;
            if (value instanceof List<?>) {
                this.listValue = true;
            } else {
                this.singleValue = true;
            }
        }

        protected Criterion(String condition, Object value) {
            this(condition, value, null);
        }

        protected Criterion(String condition, Object value, Object secondValue, String typeHandler) {
            super();
            this.condition = condition;
            this.value = value;
            this.secondValue = secondValue;
            this.typeHandler = typeHandler;
            this.betweenValue = true;
        }

        protected Criterion(String condition, Object value, Object secondValue) {
            this(condition, value, secondValue, null);
        }
    }
}

2.3 生成studentMapper.java

package com.sx.kak.mapper;

import com.sx.kak.po.Student;
import com.sx.kak.po.StudentExample;
import java.util.List;
import org.apache.ibatis.annotations.Param;

public interface StudentMapper {
    int countByExample(StudentExample example);

    int deleteByExample(StudentExample example);

    int deleteByPrimaryKey(Integer id);

    int insert(Student record);

    int insertSelective(Student record);

    List<Student> selectByExample(StudentExample example);

    Student selectByPrimaryKey(Integer id);

    int updateByExampleSelective(@Param("record") Student record, @Param("example") StudentExample example);

    int updateByExample(@Param("record") Student record, @Param("example") StudentExample example);

    int updateByPrimaryKeySelective(Student record);

    int updateByPrimaryKey(Student record);
}

2.4 生成StudentMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.sx.kak.mapper.StudentMapper" >
  <resultMap id="BaseResultMap" type="com.sx.kak.po.Student" >
    <id column="id" property="id" jdbcType="INTEGER" />
    <result column="NAME" property="name" jdbcType="VARCHAR" />
    <result column="sex" property="sex" jdbcType="VARCHAR" />
    <result column="age" property="age" jdbcType="VARCHAR" />
  </resultMap>
  <sql id="Example_Where_Clause" >
    <where >
      <foreach collection="oredCriteria" item="criteria" separator="or" >
        <if test="criteria.valid" >
          <trim prefix="(" suffix=")" prefixOverrides="and" >
            <foreach collection="criteria.criteria" item="criterion" >
              <choose >
                <when test="criterion.noValue" >
                  and ${criterion.condition}
                </when>
                <when test="criterion.singleValue" >
                  and ${criterion.condition} #{criterion.value}
                </when>
                <when test="criterion.betweenValue" >
                  and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
                </when>
                <when test="criterion.listValue" >
                  and ${criterion.condition}
                  <foreach collection="criterion.value" item="listItem" open="(" close=")" separator="," >
                    #{listItem}
                  </foreach>
                </when>
              </choose>
            </foreach>
          </trim>
        </if>
      </foreach>
    </where>
  </sql>
  <sql id="Update_By_Example_Where_Clause" >
    <where >
      <foreach collection="example.oredCriteria" item="criteria" separator="or" >
        <if test="criteria.valid" >
          <trim prefix="(" suffix=")" prefixOverrides="and" >
            <foreach collection="criteria.criteria" item="criterion" >
              <choose >
                <when test="criterion.noValue" >
                  and ${criterion.condition}
                </when>
                <when test="criterion.singleValue" >
                  and ${criterion.condition} #{criterion.value}
                </when>
                <when test="criterion.betweenValue" >
                  and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
                </when>
                <when test="criterion.listValue" >
                  and ${criterion.condition}
                  <foreach collection="criterion.value" item="listItem" open="(" close=")" separator="," >
                    #{listItem}
                  </foreach>
                </when>
              </choose>
            </foreach>
          </trim>
        </if>
      </foreach>
    </where>
  </sql>
  <sql id="Base_Column_List" >
    id, NAME, sex, age
  </sql>
  <select id="selectByExample" resultMap="BaseResultMap" parameterType="com.sx.kak.po.StudentExample" >
    select
    <if test="distinct" >
      distinct
    </if>
    <include refid="Base_Column_List" />
    from student
    <if test="_parameter != null" >
      <include refid="Example_Where_Clause" />
    </if>
    <if test="orderByClause != null" >
      order by ${orderByClause}
    </if>
  </select>
  <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
    select 
    <include refid="Base_Column_List" />
    from student
    where id = #{id,jdbcType=INTEGER}
  </select>
  <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >
    delete from student
    where id = #{id,jdbcType=INTEGER}
  </delete>
  <delete id="deleteByExample" parameterType="com.sx.kak.po.StudentExample" >
    delete from student
    <if test="_parameter != null" >
      <include refid="Example_Where_Clause" />
    </if>
  </delete>
  <insert id="insert" parameterType="com.sx.kak.po.Student" >
    insert into student (id, NAME, sex, 
      age)
    values (#{id,jdbcType=INTEGER}, #{name,jdbcType=VARCHAR}, #{sex,jdbcType=VARCHAR}, 
      #{age,jdbcType=VARCHAR})
  </insert>
  <insert id="insertSelective" parameterType="com.sx.kak.po.Student" >
    insert into student
    <trim prefix="(" suffix=")" suffixOverrides="," >
      <if test="id != null" >
        id,
      </if>
      <if test="name != null" >
        NAME,
      </if>
      <if test="sex != null" >
        sex,
      </if>
      <if test="age != null" >
        age,
      </if>
    </trim>
    <trim prefix="values (" suffix=")" suffixOverrides="," >
      <if test="id != null" >
        #{id,jdbcType=INTEGER},
      </if>
      <if test="name != null" >
        #{name,jdbcType=VARCHAR},
      </if>
      <if test="sex != null" >
        #{sex,jdbcType=VARCHAR},
      </if>
      <if test="age != null" >
        #{age,jdbcType=VARCHAR},
      </if>
    </trim>
  </insert>
  <select id="countByExample" parameterType="com.sx.kak.po.StudentExample" resultType="java.lang.Integer" >
    select count(*) from student
    <if test="_parameter != null" >
      <include refid="Example_Where_Clause" />
    </if>
  </select>
  <update id="updateByExampleSelective" parameterType="map" >
    update student
    <set >
      <if test="record.id != null" >
        id = #{record.id,jdbcType=INTEGER},
      </if>
      <if test="record.name != null" >
        NAME = #{record.name,jdbcType=VARCHAR},
      </if>
      <if test="record.sex != null" >
        sex = #{record.sex,jdbcType=VARCHAR},
      </if>
      <if test="record.age != null" >
        age = #{record.age,jdbcType=VARCHAR},
      </if>
    </set>
    <if test="_parameter != null" >
      <include refid="Update_By_Example_Where_Clause" />
    </if>
  </update>
  <update id="updateByExample" parameterType="map" >
    update student
    set id = #{record.id,jdbcType=INTEGER},
      NAME = #{record.name,jdbcType=VARCHAR},
      sex = #{record.sex,jdbcType=VARCHAR},
      age = #{record.age,jdbcType=VARCHAR}
    <if test="_parameter != null" >
      <include refid="Update_By_Example_Where_Clause" />
    </if>
  </update>
  <update id="updateByPrimaryKeySelective" parameterType="com.sx.kak.po.Student" >
    update student
    <set >
      <if test="name != null" >
        NAME = #{name,jdbcType=VARCHAR},
      </if>
      <if test="sex != null" >
        sex = #{sex,jdbcType=VARCHAR},
      </if>
      <if test="age != null" >
        age = #{age,jdbcType=VARCHAR},
      </if>
    </set>
    where id = #{id,jdbcType=INTEGER}
  </update>
  <update id="updateByPrimaryKey" parameterType="com.sx.kak.po.Student" >
    update student
    set NAME = #{name,jdbcType=VARCHAR},
      sex = #{sex,jdbcType=VARCHAR},
      age = #{age,jdbcType=VARCHAR}
    where id = #{id,jdbcType=INTEGER}
  </update>
</mapper>

2.5 編寫application.yml

server:
  port: 8080
spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/db0711?characterEncoding=utf8&serverTimezone=UTC
    username: root
    password: root
mybatis:
  type-aliases-package: po
  mapper-locations: classpath:mapping/*.xml

2.6 編寫JsonUtils工具類

package com.sx.kak.utils;

import java.util.List;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.ObjectMapper;


public class JsonUtils {

    // 定義jackson物件
    private static final ObjectMapper MAPPER = new ObjectMapper();

    /**
     * 將物件轉換成json字串。
     * <p>Title: pojoToJson</p>
     * <p>Description: </p>
     * @param data
     * @return
     */
    public static String objectToJson(Object data) {
    	try {
			String string = MAPPER.writeValueAsString(data);
			return string;
		} catch (JsonProcessingException e) {
			e.printStackTrace();
		}
    	return null;
    }
    
    /**
     * 將json結果集轉化為物件
     * 
     * @param jsonData json資料
     * @param clazz 物件中的object型別
     * @return
     */
    public static <T> T jsonToPojo(String jsonData, Class<T> beanType) {
        try {
            T t = MAPPER.readValue(jsonData, beanType);
            return t;
        } catch (Exception e) {
        	e.printStackTrace();
        }
        return null;
    }
    
    /**
     * 將json資料轉換成pojo物件list
     * <p>Title: jsonToList</p>
     * <p>Description: </p>
     * @param jsonData
     * @param beanType
     * @return
     */
    public static <T>List<T> jsonToList(String jsonData, Class<T> beanType) {
    	JavaType javaType = MAPPER.getTypeFactory().constructParametricType(List.class, beanType);
    	try {
    		List<T> list = MAPPER.readValue(jsonData, javaType);
    		return list;
		} catch (Exception e) {
			e.printStackTrace();
		}
    	return null;
    }
}

2.7 編寫RedisUtils工具類

package com.sx.kak.utils;

/**
 * Created by Kak on 2020/9/17.
 */
public interface RedisUtils {
    public void hset(String key,String filed,String value);
    public String hget(String key,String field );
    public void set(String key ,String value);
    public String get (String key);
    public void expire(String key,int seconds);
    public long ttl(String key);
}

2.8 編寫RedisUtils工具類的實現類

package com.sx.kak.utils;

import redis.clients.jedis.Jedis;

/**
 * Created by Kak on 2020/9/17.
 */
public class SingleTonRedisUtil implements RedisUtils{
    private Jedis jedis;
    public SingleTonRedisUtil(Jedis jedis){
        this.jedis = jedis;
    }
    @Override
    public void hset(String key, String filed, String value) {
        jedis.hset(key, filed, value);
    }

    @Override
    public String hget(String key, String field) {
        return jedis.hget(key, field);
    }
}

2.9 設定初始化檔案

package com.sx.kak.config;

import com.sx.kak.utils.SingleTonRedisUtil;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import redis.clients.jedis.Jedis;

/**
 * Created by Kak on 2020/9/17.
 */
@Configuration
public class RedisConfig {
    @Bean
    public SingleTonRedisUtil singleTonRedisUtil(@Qualifier("jedis") Jedis jedis){
        SingleTonRedisUtil singleTonRedisUtil = new SingleTonRedisUtil(jedis);
        return singleTonRedisUtil;
    }

    @Bean(name = "jedis")
    public Jedis getJedis(){
        Jedis jedis = new Jedis("127.0.0.1",6379);
        return jedis;
    }
}

2.10 設定StudentService.java

package com.sx.kak.service;

import com.sx.kak.po.Student;

import java.util.List;

/**
 * Created by Kak on 2020/9/17.
 */
public interface StudentService {
    public List<Student> findAllStudent();
}

2.11 設定StudentServiceImpl.java

package com.sx.kak.service.serviceImpl;

import com.sx.kak.mapper.StudentMapper;
import com.sx.kak.po.Student;
import com.sx.kak.po.StudentExample;
import com.sx.kak.service.StudentService;
import com.sx.kak.utils.JsonUtils;
import com.sx.kak.utils.SingleTonRedisUtil;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

/**
 * Created by Kak on 2020/9/17.
 */
@Service
@Slf4j
public class StudentServiceImpl implements StudentService {
    @Autowired(required = false)
    private StudentMapper studentMapper;
    //注入自定義的redis工具
    @Autowired
    private SingleTonRedisUtil redisUtil;

    @Override
    public List<Student> findAllStudent() {
        //獲取redis中存出的json字串
        String student = redisUtil.hget("student", "0");
        if(student!=null){
            log.info("get student from redis");
            //json物件，封裝的物件型別
            List<Student> students = JsonUtils.jsonToList(student, Student.class);
            return students;
        }
        //建立查詢模板物件
        StudentExample studentExample = new StudentExample();
        List<Student> students = studentMapper.selectByExample(studentExample);
        log.info("get student from db");
        try{
            //將查詢的集合轉化為json字串
            String s = JsonUtils.objectToJson(students);
            //放入redis中
            redisUtil.hset("student","0",s);
            log.info("set data to redis");
        }catch (Exception ex){
            log.info(ex.getMessage());
        }
        return students;
    }
}

2.12 編寫全查展示頁面

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8"/>
    <title>學生全查頁面</title>
</head>

<body>
<div id="findAll">
    <table>
        <tr>
            <th>ID</th>
            <th>NAME</th>
            <th>SEX</th>
            <th>AGE</th>
            <th>Action</th>
        </tr>
        <tr th:each="s:${students}">
            <td th:text="${s.id}"></td>
            <td th:text="${s.name}"></td>
            <td th:text="${s.sex}"></td>
            <td th:text="${s.age}"></td>
        </tr>
    </table>
</div>
</body>
</html>

2.13 編寫StudentController

package com.sx.kak.Controller;

import com.sx.kak.po.Student;
import com.sx.kak.service.StudentService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

/**
 * Created by Kak on 2020/9/17.
 */
@Controller
public class StudentController {
    @Autowired(required = false)
    private StudentService studentService;

    @RequestMapping("/findStudent")
    public String findAllStu(Model model){
        List<Student> allStudent = studentService.findAllStudent();
        model.addAttribute("students",allStudent);
        return "showAllStudent";
    }
}

在這裡插入圖片描述

3. 結果

從列印出的紀錄檔可以看出，第一次存取是從資料庫得到資料，然後存入redis中

第二次直接從redis中獲取

在這裡插入圖片描述

Redis在Java中的使用及連線資料庫（附原始碼）

Redis在Java中的使用及連線資料庫（附原始碼）

文章目錄

1. 在IDEA中搭建Redis

1.1 建立專案

1.2 新增依賴（不夠手動新增）

1.3 測試環境是否搭建成功

1.4 利用json儲存資料

1.5 以byte的形式儲存物件

1.6 加入連線池的操作

1.7 管道操作

2. 從資料中查詢資料

2.1 生成實體類

2.2 生成實體模板類

2.3 生成studentMapper.java

2.4 生成StudentMapper.xml

2.5 編寫application.yml

2.6 編寫JsonUtils工具類

2.7 編寫RedisUtils工具類

2.8 編寫RedisUtils工具類的實現類

2.9 設定初始化檔案

2.10 設定StudentService.java

2.11 設定StudentServiceImpl.java

2.12 編寫全查展示頁面

2.13 編寫StudentController

3. 結果