5.mybatis的CURD操作
阿新 • • 發佈：2017-08-08
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5.mybatis的CURD操作
1.導包（使用maven創建工程，導包只需要配置pom.xml即可，此處導入jackson是為測試查詢打印結果）
<?xml version="1.0" encoding="UTF-8"?> <!-- $Id: pom.xml 642118 2008-03-28 08:04:16Z reinhard $ --> <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> <packaging>jar</packaging> <name>Mybatis01</name> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <configuration> <source>1.8</source> <target>1.8</target> </configuration> </plugin> </plugins> </build> <groupId>Mybatis01</groupId> <artifactId>Mybatis01</artifactId> <version>1.0-SNAPSHOT</version> <dependencies> <!--junit依賴--> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.10</version> <scope>test</scope> </dependency> <!--mybatis依賴--> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.4.4</version> </dependency> <!--jackson2.1.0依賴--> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-core</artifactId> <version>2.2.1</version> </dependency> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <version>2.2.1</version> </dependency> <dependency> <groupId>org.junit.jupiter</groupId> <artifactId>junit-jupiter-api</artifactId> <version>RELEASE</version> </dependency> <!--mysql驅動依賴--> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.43</version> </dependency> </dependencies> </project>
2.配置mybatis核心文件mybatis.xml
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration> <!-- 加載配置文件,只能放在這個位置--> <properties resource="db.properties"></properties> <settings> <setting name="useGeneratedKeys" value="false"/> <setting name="useColumnLabel" value="true"/> </settings> <!-- 配置對應的javabean的路徑,應用別名--> <typeAliases> <typeAlias alias="Person" type="entity.Person"/> </typeAliases> <!-- 配置數據庫的連接信息 --> <environments default="development"> <environment id="development"> <transactionManager type="JDBC"> <property name="" value=""/> </transactionManager> <!--使用連接池方式獲取連接--> <dataSource type="POOLED"> <!--配置數據庫連接的信息--> <property name="driver" value="${mysql.driver}"/> <property name="url" value="${mysql.url}"/> <property name="username" value="${mysql.username}"/> <property name="password" value="${mysql.password}"/> </dataSource> </environment> </environments> <!-- 配置映射類xml文件的路徑 --> <mappers> <mapper resource="mappers/PersonMapper.xml"/> </mappers> </configuration>
3.創建sqlSession的工具類
package util; import org.apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; import java.io.IOException; import java.io.Reader; /** * 工具類 * Created by Administrator on 2017/8/6. */ public class MybatisUtil { private static ThreadLocal<SqlSession> threadLocal = new ThreadLocal<SqlSession>(); private static SqlSessionFactory sqlSessionFactory; /** * 加載位於src/mybatis.xml配置文件 */ static { try { Reader reader = Resources.getResourceAsReader("mybatis.xml"); sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader); } catch (IOException e) { e.printStackTrace(); throw new RuntimeException(e); } } /** * 禁止外界通過new方法直接創建,否則會不斷運行影響性能 * 使用方法：將這個類的構造方法設置為私有 */ private MybatisUtil() { } /** * 獲取SqlSession * * @return sqlSession */ public static SqlSession getSqlSession() { //從當前線程中獲取sqlsession對象 SqlSession sqlSession = threadLocal.get(); //如果sqlSession對象為空則從sqlSessionFacety中從新獲取 if (sqlSession == null) { sqlSession = sqlSessionFactory.openSession(); //將sqlSession與當前線程進行綁定 threadLocal.set(sqlSession); } return sqlSession; } /** * 關閉SqlSession與當前線程分開 */ public static void closeSqlSession() { //從當前線程中獲取sqlSession SqlSession sqlSession = threadLocal.get(); //如果sqlSession不為空則關閉它，並且分離線程：如不分離線程，則會數據庫操作會越來越慢 if (sqlSession != null) { sqlSession.close(); threadLocal.remove();//讓GC盡快回收，釋放內存 } } }
3.1測試工具類
import util.MybatisUtil; import java.sql.Connection; /** * Created by Administrator on 2017/8/6. * 測試獲取qlSession */ public class test1 { public static void main(String[] args) { Connection conn = MybatisUtil.getSqlSession().getConnection(); System.out.println(conn != null?"連接成功!":"連接失敗!"); } }
4.創建javabean，註意：一定要寫無參的構造函數，
防止後面要使用帶參的構造函數會覆蓋，會出現mybatis無法創建JavaBean導致查詢失敗
5.配置Mapper.xml文件，並將配置文件的路徑配置加到mybatis.xml中
package entity; /** * Created by Administrator on 2017/8/5. * Person的實體類 */ public class Person { private Integer id; private String name; private Integer age; private String remark; /*mybatis對應的javabean中必須得有一個默認無參的構造函數， * 如果我們自定義了有參的構造函數時，會將其覆蓋，執行查詢時， *mybatis無法將參數存入，所以要將其顯性的寫出來 */ public Person () { } //全參數的構造函數 public Person (Integer id, String name, Integer age,String remark) { super(); this.id = id; this.name = name; this.age = age; this.remark = remark; } //不含id的構造函數 public Person (String name, Integer age,String remark) { super(); this.name = name; this.age = age; this.remark = remark; } 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; } public Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } public String getRemark() { return remark; } public void setRemark(String remark) { this.remark = remark; } }
6.書寫JavaBean的Dao類
package dao; import entity.Person; import org.apache.ibatis.jdbc.SQL; import org.apache.ibatis.session.SqlSession; import util.MybatisUtil; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; /** * Created by Administrator on 2017/8/6. */ public class PersonDao { //*****************************************急速入門******************************************** //增加一條信息 public Integer addPerson (Person person){ try { SqlSession sqlSession = MybatisUtil.getSqlSession(); Integer i = sqlSession.insert("Person.addPerson",person); sqlSession.commit(); return i; } catch (Exception e) { e.printStackTrace(); return -1; } finally { MybatisUtil.closeSqlSession(); } } //根據id刪除人員信息 public Integer deletePersonById (int id) { try { SqlSession sqlSession = MybatisUtil.getSqlSession(); Integer i = sqlSession.delete("Person.deletePersonById",id); sqlSession.commit(); return i; } catch (Exception e) { e.printStackTrace(); return -1; } finally { MybatisUtil.closeSqlSession(); } } //根據id修改一個人的信息 public Integer updatePersonById (Person person) { try { SqlSession sqlSession = MybatisUtil.getSqlSession(); Integer i = sqlSession.update("Person.updatePersonById",person); sqlSession.commit(); return i; } catch (Exception e) { e.printStackTrace(); return -1; } finally { MybatisUtil.closeSqlSession(); } } //通過id獲取person public Person getPersonById (int id) { try { SqlSession sqlSession = MybatisUtil.getSqlSession(); Person person = sqlSession.selectOne("Person.getPersonById",id); return person; } catch (Exception e) { e.printStackTrace(); return null; } finally { MybatisUtil.closeSqlSession(); } } //根據分頁查詢 public List<Person> getPersonList (Integer start, Integer limit) { try { SqlSession sqlSession = MybatisUtil.getSqlSession(); Map<String, Object> map = new HashMap<String, Object>(); map.put("start", start); map.put("limit", limit); List<Person> li = sqlSession.selectList("Person.getPersonList",map); return li; } catch (Exception e) { e.printStackTrace(); return null; } finally { MybatisUtil.closeSqlSession(); } } //*****************************************動態CRUD,mybatis相較於hibernate的優勢******************************************** /** * 根據三個條件中的任意一個或多個進行動態查詢 * @param name * @param age * @param remark * @return */ public List<Person> getPersonLList2 (String name, Integer age, String remark) { try { SqlSession sqlSession = MybatisUtil.getSqlSession(); Map<String, Object> map = new HashMap<String, Object>(); map.put("name",name); map.put("age",age); map.put("remark",remark); List<Person> li = sqlSession.selectList("Person.getPersonList2",map); return li; } catch (Exception e) { e.printStackTrace(); return new ArrayList<Person>(); } finally { MybatisUtil.closeSqlSession(); } } public Integer updatePerson1 (Person person) { try{ SqlSession sqlSession = MybatisUtil.getSqlSession(); Integer i = sqlSession.update("Person.updatePerson1",person); sqlSession.commit(); return i; }catch (Exception e) { e.printStackTrace(); return -1; }finally { MybatisUtil.closeSqlSession(); } } public Integer deletePerson1 (int... id) { try { SqlSession sqlSession = MybatisUtil.getSqlSession(); Integer i = sqlSession.delete("Person.deldetPerson1",id); sqlSession.commit(); return i; } catch (Exception e) { e.printStackTrace(); return -1; } finally { MybatisUtil.closeSqlSession(); } } public Integer addPerson1 (Person person) { try { SqlSession sqlSession = MybatisUtil.getSqlSession(); Integer i = sqlSession.insert("Person.addPerson1",person); sqlSession.commit(); return i; } catch (Exception e) { e.printStackTrace(); return -1; }finally { MybatisUtil.closeSqlSession(); } } }
7.測試（其他測試類以此類推）
import util.MybatisUtil; import java.sql.Connection; /** * Created by Administrator on 2017/8/6. * 測試獲取qlSession */ public class test1 { public static void main(String[] args) { Connection conn = MybatisUtil.getSqlSession().getConnection(); System.out.println(conn != null?"連接成功!":"連接失敗!"); } }
8.項目文件結構
package util;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import java.io.IOException;
import java.io.Reader;
/**
* 工具類
* Created by Administrator on 2017/8/6.
*/
public class MybatisUtil {
private static ThreadLocal<SqlSession> threadLocal = new ThreadLocal<SqlSession>();
private static SqlSessionFactory sqlSessionFactory;
/**
* 加載位於src/mybatis.xml配置文件
*/
static {
try {
Reader reader = Resources.getResourceAsReader("mybatis.xml");
sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
} catch (IOException e) {
e.printStackTrace();
throw new RuntimeException(e);
}
}
/**
* 禁止外界通過new方法直接創建,否則會不斷運行影響性能
* 使用方法：將這個類的構造方法設置為私有
*/
private MybatisUtil() {
}
/**
* 獲取SqlSession
*
* @return sqlSession
*/
public static SqlSession getSqlSession() {
//從當前線程中獲取sqlsession對象
SqlSession sqlSession = threadLocal.get();
//如果sqlSession對象為空則從sqlSessionFacety中從新獲取
if (sqlSession == null) {
sqlSession = sqlSessionFactory.openSession();
//將sqlSession與當前線程進行綁定
threadLocal.set(sqlSession);
}
return sqlSession;
}
/**
* 關閉SqlSession與當前線程分開
*/
public static void closeSqlSession() {
//從當前線程中獲取sqlSession
SqlSession sqlSession = threadLocal.get();
//如果sqlSession不為空則關閉它，並且分離線程：如不分離線程，則會數據庫操作會越來越慢
if (sqlSession != null) {
sqlSession.close();
threadLocal.remove();//讓GC盡快回收，釋放內存
}
}
}
5.mybatis的CURD操作