1、C3P0是一个开源的JDBC连接池，它实现了数据源和JNDI绑定，支持JDBC3规范和JDBC2的标准扩展，同时在Hibernate、Spring项目开发中被广泛应用。修改项目的pom.xml配置文件，添加C3P0依赖支持管理，由于要连接mysql，所以也要加入mysql的依赖包，如下所示：
代码语言：javascript复制 1 <?xml version="1.0" encoding="UTF-8"?>
2 <project xmlns="http://maven.apache.org/POM/4.0.0"
3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
5 https://maven.apache.org/xsd/maven-4.0.0.xsd">
6
7 <modelVersion>4.0.0</modelVersion>
8 <parent>
9 <!-- spring-boot-starter-parent就是官方给出的快速构建SpringBoot项目的公共父pom.xml配置文件支持。 -->
10 <groupId>org.springframework.boot</groupId>
11 <artifactId>spring-boot-starter-parent</artifactId>
12 <version>2.3.4.RELEASE</version>
13 <relativePath /> <!-- lookup parent from repository -->
14 </parent>
15
16 <groupId>com.bie</groupId>
17 <artifactId>springboot-01</artifactId>
18 <version>0.0.1-SNAPSHOT</version>
19 <name>springboot-01</name>
20 <description>Demo project for Spring Boot</description>
21
22 <properties>
23 <java.version>1.8</java.version>
24 <maven-jar-plugin.version>3.1.1</maven-jar-plugin.version>
25 </properties>
26
27 <dependencies>
28 <dependency>
29 <groupId>org.springframework.boot</groupId>
30 <artifactId>spring-boot-starter-web</artifactId>
31 </dependency>
32
33 <dependency>
34 <groupId>org.springframework.boot</groupId>
35 <artifactId>spring-boot-starter-test</artifactId>
36 <scope>test</scope>
37 <exclusions>
38 <exclusion>
39 <groupId>org.junit.vintage</groupId>
40 <artifactId>junit-vintage-engine</artifactId>
41 </exclusion>
42 </exclusions>
43 </dependency>
44 <!-- https://mvnrepository.com/artifact/com.mchange/c3p0 -->
45 <dependency>
46 <groupId>com.mchange</groupId>
47 <artifactId>c3p0</artifactId>
48 <version>0.9.5.2</version>
49 </dependency>
50 <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
51 <dependency>
52 <groupId>mysql</groupId>
53 <artifactId>mysql-connector-java</artifactId>
54 <!-- <version>5.1.12</version> -->
55 </dependency>
56 <dependency>
57 <groupId>org.springframework.boot</groupId>
58 <artifactId>spring-boot-configuration-processor</artifactId>
59 <optional>true</optional>
60 </dependency>
61 </dependencies>
62
63 <build>
64 <plugins>
65 <plugin>
66 <groupId>org.springframework.boot</groupId>
67 <artifactId>spring-boot-maven-plugin</artifactId>
68 </plugin>
69 </plugins>
70 </build>
71
72 </project>然后，更新项目，Maven -> Update Project，修改application.yml配置文件，追加C3P0数据库连接池配置信息。
代码语言：javascript复制 1 # 定义c3p0的配置，没有提示可以使用，数据库连接地址
2 c3p0.jdbcUrl=jdbc:mysql://localhost:3306/biehl?serverTimezone=UTC
3 # 数据库用户名
4 c3p0.user=root
5 # 数据库密码
6 c3p0.password=123456
7 # 数据库驱动程序
8 c3p0.driverClass=com.mysql.jdbc.Driver
9 # 最小连接数
10 c3p0.minPoolSize=2
11 # 最大连接数
12 c3p0.maxPoolSize=10
13 # 最大等待时间
14 c3p0.maxIdleTime=3000
15 # 初始化连接数
16 c3p0.initialPoolSize=3定义c3p0的配置的时候，没有提示可以使用，数据库连接地址后面要加上?serverTimezone=UTC，不然报下面的错误，如下所示：
高版本的 spring boot搭配mysql 驱动版本较高时，如 mysql-connector-java:8.0.16，此时 driver-class-name 的值要带 cj（可不带），url 的值要带时区 serverTimezone（要带）。
代码语言：javascript复制 1 . ____ _ __ _ _
2 /\ / ___'_ __ _ _(_)_ __ __ _
3 ( ( )___ | '_ | '_| | '_ / _` |
4 \/ ___)| |_)| | | | | || (_| | ) ) ) )
5 ' |____| .__|_| |_|_| |___, | / / / /
6 =========|_|==============|___/=/_/_/_/
7 :: Spring Boot :: (v2.3.4.RELEASE)
8
9 2020-11-15 11:17:01.181 INFO 4908 --- [ main] com.bie.Springboot01ApplicationTests : Starting Springboot01ApplicationTests on DESKTOP-V37QSSE with PID 4908 (started by biehl in E:eclipseeclipseworkspace_springbootspringboot-01)
10 2020-11-15 11:17:01.182 INFO 4908 --- [ main] com.bie.Springboot01ApplicationTests : No active profile set, falling back to default profiles: default
11 2020-11-15 11:17:01.885 INFO 4908 --- [g-Init-Reporter] com.mchange.v2.log.MLog : MLog clients using slf4j logging.
12 2020-11-15 11:17:02.796 INFO 4908 --- [ main] com.mchange.v2.c3p0.C3P0Registry : Initializing c3p0-0.9.5.2 [built 08-December-2015 22:06:04 -0800; debug? true; trace: 10]
13 2020-11-15 11:17:03.307 INFO 4908 --- [ main] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor'
14 2020-11-15 11:17:03.652 INFO 4908 --- [ main] com.bie.Springboot01ApplicationTests : Started Springboot01ApplicationTests in 2.803 seconds (JVM running for 4.051)
15 2020-11-15 11:17:03.950 INFO 4908 --- [ main] c.m.v.c.i.AbstractPoolBackedDataSource : Initializing c3p0 pool... com.mchange.v2.c3p0.ComboPooledDataSource [ acquireIncrement -> 3, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, contextClassLoaderSource -> caller, dataSourceName -> 1hgemn5ad1k0s6dw1kn7og9|3be8821f, debugUnreturnedConnectionStackTraces -> false, description -> null, driverClass -> com.mysql.jdbc.Driver, extensions -> {}, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, forceSynchronousCheckins -> false, forceUseNamedDriverClass -> false, identityToken -> 1hgemn5ad1k0s6dw1kn7og9|3be8821f, idleConnectionTestPeriod -> 0, initialPoolSize -> 3, jdbcUrl -> jdbc:mysql://localhost:3306/biehl, maxAdministrativeTaskTime -> 0, maxConnectionAge -> 0, maxIdleTime -> 1800000, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 10, maxStatements -> 0, maxStatementsPerConnection -> 0, minPoolSize -> 2, numHelperThreads -> 3, preferredTestQuery -> null, privilegeSpawnedThreads -> false, properties -> {user=******, password=******}, propertyCycle -> 0, statementCacheNumDeferredCloseThreads -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, userOverrides -> {}, usesTraditionalReflectiveProxies -> false ]
16 Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.
17 2020-11-15 11:17:34.489 WARN 4908 --- [HelperThread-#2] c.m.v2.resourcepool.BasicResourcePool : com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@2c34448d -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception:
18
19 java.sql.SQLException: The server time zone value '�й���ʱ��' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the 'serverTimezone' configuration property) to use a more specifc time zone value if you want to utilize time zone support.
20 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:129) ~[mysql-connector-java-8.0.21.jar:8.0.21]
21 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97) ~[mysql-connector-java-8.0.21.jar:8.0.21]
22 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:89) ~[mysql-connector-java-8.0.21.jar:8.0.21]
23 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:63) ~[mysql-connector-java-8.0.21.jar:8.0.21]
24 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:73) ~[mysql-connector-java-8.0.21.jar:8.0.21]
25 at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:76) ~[mysql-connector-java-8.0.21.jar:8.0.21]
26 at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:836) ~[mysql-connector-java-8.0.21.jar:8.0.21]
27 at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:456) ~[mysql-connector-java-8.0.21.jar:8.0.21]
28 at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:246) ~[mysql-connector-java-8.0.21.jar:8.0.21]
29 at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:197) ~[mysql-connector-java-8.0.21.jar:8.0.21]
30 at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:175) ~[c3p0-0.9.5.2.jar:0.9.5.2]
31 at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:220) ~[c3p0-0.9.5.2.jar:0.9.5.2]
32 at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:206) ~[c3p0-0.9.5.2.jar:0.9.5.2]
33 at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:203) ~[c3p0-0.9.5.2.jar:0.9.5.2]
34 at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138) ~[c3p0-0.9.5.2.jar:0.9.5.2]
35 at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125) ~[c3p0-0.9.5.2.jar:0.9.5.2]
36 at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44) ~[c3p0-0.9.5.2.jar:0.9.5.2]
37 at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870) ~[c3p0-0.9.5.2.jar:0.9.5.2]
38 at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696) [mchange-commons-java-0.2.11.jar:0.2.11]
39 Caused by: com.mysql.cj.exceptions.InvalidConnectionAttributeException: The server time zone value '�й���ʱ��' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the 'serverTimezone' configuration property) to use a more specifc time zone value if you want to utilize time zone support.
40 at sun.reflect.GeneratedConstructorAccessor27.newInstance(Unknown Source) ~[na:na]
41 at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) ~[na:1.8.0_191]
42 at java.lang.reflect.Constructor.newInstance(Unknown Source) ~[na:1.8.0_191]
43 at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61) ~[mysql-connector-java-8.0.21.jar:8.0.21]
44 at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:85) ~[mysql-connector-java-8.0.21.jar:8.0.21]
45 at com.mysql.cj.util.TimeUtil.getCanonicalTimezone(TimeUtil.java:132) ~[mysql-connector-java-8.0.21.jar:8.0.21]
46 at com.mysql.cj.protocol.a.NativeProtocol.configureTimezone(NativeProtocol.java:2120) ~[mysql-connector-java-8.0.21.jar:8.0.21]
47 at com.mysql.cj.protocol.a.NativeProtocol.initServerSession(NativeProtocol.java:2143) ~[mysql-connector-java-8.0.21.jar:8.0.21]
48 at com.mysql.cj.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:1310) ~[mysql-connector-java-8.0.21.jar:8.0.21]
49 at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:967) ~[mysql-connector-java-8.0.21.jar:8.0.21]
50 at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:826) ~[mysql-connector-java-8.0.21.jar:8.0.21]
51 ... 12 common frames omitted
52
53 2020-11-15 11:17:34.492 WARN 4908 --- [HelperThread-#2] c.m.v2.resourcepool.BasicResourcePool : Having failed to acquire a resource, com.mchange.v2.resourcepool.BasicResourcePool@51a8313b is interrupting all Threads waiting on a resource to check out. Will try again in response to new client requests.
54 2020-11-15 11:17:34.495 WARN 4908 --- [HelperThread-#0] c.m.v2.resourcepool.BasicResourcePool : com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@bf450d2 -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception:
55
56 java.sql.SQLException: The server time zone value '�й���ʱ��' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the 'serverTimezone' configuration property) to use a more specifc time zone value if you want to utilize time zone support.
57 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:129) ~[mysql-connector-java-8.0.21.jar:8.0.21]
58 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97) ~[mysql-connector-java-8.0.21.jar:8.0.21]
59 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:89) ~[mysql-connector-java-8.0.21.jar:8.0.21]
60 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:63) ~[mysql-connector-java-8.0.21.jar:8.0.21]
61 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:73) ~[mysql-connector-java-8.0.21.jar:8.0.21]
62 at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:76) ~[mysql-connector-java-8.0.21.jar:8.0.21]
63 at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:836) ~[mysql-connector-java-8.0.21.jar:8.0.21]
64 at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:456) ~[mysql-connector-java-8.0.21.jar:8.0.21]
65 at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:246) ~[mysql-connector-java-8.0.21.jar:8.0.21]
66 at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:197) ~[mysql-connector-java-8.0.21.jar:8.0.21]
67 at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:175) ~[c3p0-0.9.5.2.jar:0.9.5.2]
68 at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:220) ~[c3p0-0.9.5.2.jar:0.9.5.2]
69 at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:206) ~[c3p0-0.9.5.2.jar:0.9.5.2]
70 at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:203) ~[c3p0-0.9.5.2.jar:0.9.5.2]
71 at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138) ~[c3p0-0.9.5.2.jar:0.9.5.2]
72 at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125) ~[c3p0-0.9.5.2.jar:0.9.5.2]
73 at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44) ~[c3p0-0.9.5.2.jar:0.9.5.2]
74 at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870) ~[c3p0-0.9.5.2.jar:0.9.5.2]
75 at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696) [mchange-commons-java-0.2.11.jar:0.2.11]
76 Caused by: com.mysql.cj.exceptions.InvalidConnectionAttributeException: The server time zone value '�й���ʱ��' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the 'serverTimezone' configuration property) to use a more specifc time zone value if you want to utilize time zone support.
77 at sun.reflect.GeneratedConstructorAccessor27.newInstance(Unknown Source) ~[na:na]
78 at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) ~[na:1.8.0_191]
79 at java.lang.reflect.Constructor.newInstance(Unknown Source) ~[na:1.8.0_191]
80 at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61) ~[mysql-connector-java-8.0.21.jar:8.0.21]
81 at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:85) ~[mysql-connector-java-8.0.21.jar:8.0.21]
82 at com.mysql.cj.util.TimeUtil.getCanonicalTimezone(TimeUtil.java:132) ~[mysql-connector-java-8.0.21.jar:8.0.21]
83 at com.mysql.cj.protocol.a.NativeProtocol.configureTimezone(NativeProtocol.java:2120) ~[mysql-connector-java-8.0.21.jar:8.0.21]
84 at com.mysql.cj.protocol.a.NativeProtocol.initServerSession(NativeProtocol.java:2143) ~[mysql-connector-java-8.0.21.jar:8.0.21]
85 at com.mysql.cj.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:1310) ~[mysql-connector-java-8.0.21.jar:8.0.21]
86 at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:967) ~[mysql-connector-java-8.0.21.jar:8.0.21]
87 at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:826) ~[mysql-connector-java-8.0.21.jar:8.0.21]
88 ... 12 common frames omitted
89
90 2020-11-15 11:17:34.495 WARN 4908 --- [HelperThread-#0] c.m.v2.resourcepool.BasicResourcePool : Having failed to acquire a resource, com.mchange.v2.resourcepool.BasicResourcePool@51a8313b is interrupting all Threads waiting on a resource to check out. Will try again in response to new client requests.
91 2020-11-15 11:17:34.495 WARN 4908 --- [HelperThread-#1] c.m.v2.resourcepool.BasicResourcePool : com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@6ed18a76 -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception:
92
93 java.sql.SQLException: The server time zone value '�й���ʱ��' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the 'serverTimezone' configuration property) to use a more specifc time zone value if you want to utilize time zone support.
94 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:129) ~[mysql-connector-java-8.0.21.jar:8.0.21]
95 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97) ~[mysql-connector-java-8.0.21.jar:8.0.21]
96 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:89) ~[mysql-connector-java-8.0.21.jar:8.0.21]
97 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:63) ~[mysql-connector-java-8.0.21.jar:8.0.21]
98 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:73) ~[mysql-connector-java-8.0.21.jar:8.0.21]
99 at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:76) ~[mysql-connector-java-8.0.21.jar:8.0.21]
100 at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:836) ~[mysql-connector-java-8.0.21.jar:8.0.21]
101 at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:456) ~[mysql-connector-java-8.0.21.jar:8.0.21]
102 at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:246) ~[mysql-connector-java-8.0.21.jar:8.0.21]
103 at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:197) ~[mysql-connector-java-8.0.21.jar:8.0.21]
104 at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:175) ~[c3p0-0.9.5.2.jar:0.9.5.2]
105 at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:220) ~[c3p0-0.9.5.2.jar:0.9.5.2]
106 at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:206) ~[c3p0-0.9.5.2.jar:0.9.5.2]
107 at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:203) ~[c3p0-0.9.5.2.jar:0.9.5.2]
108 at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138) ~[c3p0-0.9.5.2.jar:0.9.5.2]
109 at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125) ~[c3p0-0.9.5.2.jar:0.9.5.2]
110 at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44) ~[c3p0-0.9.5.2.jar:0.9.5.2]
111 at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870) ~[c3p0-0.9.5.2.jar:0.9.5.2]
112 at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696) [mchange-commons-java-0.2.11.jar:0.2.11]
113 Caused by: com.mysql.cj.exceptions.InvalidConnectionAttributeException: The server time zone value '�й���ʱ��' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the 'serverTimezone' configuration property) to use a more specifc time zone value if you want to utilize time zone support.
114 at sun.reflect.GeneratedConstructorAccessor27.newInstance(Unknown Source) ~[na:na]
115 at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) ~[na:1.8.0_191]
116 at java.lang.reflect.Constructor.newInstance(Unknown Source) ~[na:1.8.0_191]
117 at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61) ~[mysql-connector-java-8.0.21.jar:8.0.21]
118 at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:85) ~[mysql-connector-java-8.0.21.jar:8.0.21]
119 at com.mysql.cj.util.TimeUtil.getCanonicalTimezone(TimeUtil.java:132) ~[mysql-connector-java-8.0.21.jar:8.0.21]
120 at com.mysql.cj.protocol.a.NativeProtocol.configureTimezone(NativeProtocol.java:2120) ~[mysql-connector-java-8.0.21.jar:8.0.21]
121 at com.mysql.cj.protocol.a.NativeProtocol.initServerSession(NativeProtocol.java:2143) ~[mysql-connector-java-8.0.21.jar:8.0.21]
122 at com.mysql.cj.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:1310) ~[mysql-connector-java-8.0.21.jar:8.0.21]
123 at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:967) ~[mysql-connector-java-8.0.21.jar:8.0.21]
124 at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:826) ~[mysql-connector-java-8.0.21.jar:8.0.21]
125 ... 12 common frames omitted
126
127 2020-11-15 11:17:34.496 WARN 4908 --- [HelperThread-#1] c.m.v2.resourcepool.BasicResourcePool : Having failed to acquire a resource, com.mchange.v2.resourcepool.BasicResourcePool@51a8313b is interrupting all Threads waiting on a resource to check out. Will try again in response to new client requests.
128 2020-11-15 11:17:34.519 INFO 4908 --- [extShutdownHook] o.s.s.concurrent.ThreadPoolTaskExecutor : Shutting down ExecutorService 'applicationTaskExecutor'建立C3P0数据源连接池配置类，此时设置的Bean名称为dataSource。
代码语言：javascript复制 1 package com.bie.config;
2
3 import javax.sql.DataSource;
4
5 import org.springframework.boot.context.properties.ConfigurationProperties;
6 import org.springframework.boot.jdbc.DataSourceBuilder;
7 import org.springframework.context.annotation.Bean;
8 import org.springframework.context.annotation.Configuration;
9
10 @Configuration
11 public class C3p0DatasourceConfig {
12
13 // c3p0 连接池
14 @Bean(name = "dataSource")
15 @ConfigurationProperties(prefix = "c3p0")
16 public DataSource dataSource() {
17 return DataSourceBuilder.create().type(com.mchange.v2.c3p0.ComboPooledDataSource.class).build();
18 }
19
20 }编写Junit测试类，测试当前DataSource配置是否正确。
代码语言：javascript复制 1 package com.bie;
2
3 import java.sql.Connection;
4 import java.sql.PreparedStatement;
5 import java.sql.ResultSet;
6 import java.sql.SQLException;
7
8 import javax.sql.DataSource;
9
10 import org.junit.jupiter.api.Test;
11 import org.junit.runner.RunWith;
12 import org.springframework.beans.factory.annotation.Autowired;
13 import org.springframework.boot.test.context.SpringBootTest;
14 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
15 import org.springframework.test.context.web.WebAppConfiguration;
16
17 @SpringBootTest(classes = Springboot01Application.class) // 定义要测试的Springboot类
18 @RunWith(SpringJUnit4ClassRunner.class) // 使用Junit进行测试
19 @WebAppConfiguration // 进行Web应用配置
20 class Springboot01ApplicationTests {
21
22 @Autowired
23 private DataSource dataSource; // 注入DataSource对象
24
25 @Test
26 void testConnection() throws SQLException {
27 // 获取连接
28 Connection connection = this.dataSource.getConnection();
29 System.out.println(connection);
30
31 String sql = "select * from user_info ";
32 PreparedStatement ps = connection.prepareStatement(sql);
33 ResultSet rs = ps.executeQuery();
34 UserInfo users = null;
35 if (rs.next()) {
36 users = new UserInfo();
37 // 从数据库中获取值设置到实体类的setter方法中
38 users.setUserId(rs.getInt("user_id"));
39 users.setUserAccount(rs.getString("user_account"));
40 users.setUserPw(rs.getString("user_pw"));
41 users.setUserNumber(rs.getString("user_number"));
42 users.setUserName(rs.getString("user_name"));
43 users.setUserAge(rs.getInt("user_age"));
44 users.setUserSex(rs.getString("user_sex"));
45 users.setUserMark(rs.getString("user_mark"));
46 users.setIsMoney(rs.getString("is_money"));
47 System.out.println(users.toString());
48 }
49 }
50
51 // 内部类
52 class UserInfo {
53 private Integer userId;// 用户编号
54 private String userAccount;// 用户账号
55 private String userPw;// 用户密码
56 private String userNumber;// 用户学号
57 private String userName;// 用户姓名
58 private Integer userAge;// 用户年龄
59 private String userSex;// 用户性别
60 private String userMark;// 用户标识，可以使用一张表，完成管理员和用户
61
62 private String isMoney;
63
64 public Integer getUserId() {
65 return userId;
66 }
67
68 public void setUserId(Integer userId) {
69 this.userId = userId;
70 }
71
72 public String getUserAccount() {
73 return userAccount;
74 }
75
76 public void setUserAccount(String userAccount) {
77 this.userAccount = userAccount;
78 }
79
80 public String getUserPw() {
81 return userPw;
82 }
83
84 public void setUserPw(String userPw) {
85 this.userPw = userPw;
86 }
87
88 public String getUserNumber() {
89 return userNumber;
90 }
91
92 public void setUserNumber(String userNumber) {
93 this.userNumber = userNumber;
94 }
95
96 public String getUserName() {
97 return userName;
98 }
99
100 public void setUserName(String userName) {
101 this.userName = userName;
102 }
103
104 public Integer getUserAge() {
105 return userAge;
106 }
107
108 public void setUserAge(Integer userAge) {
109 this.userAge = userAge;
110 }
111
112 public String getUserSex() {
113 return userSex;
114 }
115
116 public void setUserSex(String userSex) {
117 this.userSex = userSex;
118 }
119
120 public String getUserMark() {
121 return userMark;
122 }
123
124 public void setUserMark(String userMark) {
125 this.userMark = userMark;
126 }
127
128 public String getIsMoney() {
129 return isMoney;
130 }
131
132 public void setIsMoney(String isMoney) {
133 this.isMoney = isMoney;
134 }
135
136 @Override
137 public String toString() {
138 return "UserInfo [userId=" userId ", userAccount=" userAccount ", userPw=" userPw
139 ", userNumber=" userNumber ", userName=" userName ", userAge=" userAge ", userSex="
140 userSex ", userMark=" userMark ", isMoney=" isMoney "]";
141 }
142
143 }
144
145 }使用该测试类的时候，如果报下面的错误，在包资源管理器中右键单击您的项目，然后build path，然后configure build path，然后libraries-->add libraries-->junit-->添加就好了。
代码语言：javascript复制 1 java.lang.NoClassDefFoundError: org/junit/platform/launcher/core/LauncherFactory
2 at org.eclipse.jdt.internal.junit5.runner.JUnit5TestLoader.<init>(JUnit5TestLoader.java:31)
3 at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
4 at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
5 at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
6 at java.lang.reflect.Constructor.newInstance(Unknown Source)
7 at java.lang.Class.newInstance(Unknown Source)
8 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.createRawTestLoader(RemoteTestRunner.java:367)
9 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.createLoader(RemoteTestRunner.java:362)
10 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.defaultInit(RemoteTestRunner.java:306)
11 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.init(RemoteTestRunner.java:221)
12 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:205)
13 Caused by: java.lang.ClassNotFoundException: org.junit.platform.launcher.core.LauncherFactory
14 at java.net.URLClassLoader.findClass(Unknown Source)
15 at java.lang.ClassLoader.loadClass(Unknown Source)
16 at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
17 at java.lang.ClassLoader.loadClass(Unknown Source)
18 ... 11 more2、SpringBoot整合Druid数据库连接池，Druid是阿里巴巴推出的一款数据库连接池组件（可以理解为C3P0的下一代产品），也是一个用于大数据实时查询和分析的高容错、高性能开源分布式系统，可高效处理大规模的数据并实现快速查询和分析。
修改项目的pom.xml文件，引入Druid的相关依赖库，如下所示：
代码语言：javascript复制 1 <?xml version="1.0" encoding="UTF-8"?>
2 <project xmlns="http://maven.apache.org/POM/4.0.0"
3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
5 https://maven.apache.org/xsd/maven-4.0.0.xsd">
6
7 <modelVersion>4.0.0</modelVersion>
8 <parent>
9 <!-- spring-boot-starter-parent就是官方给出的快速构建SpringBoot项目的公共父pom.xml配置文件支持。 -->
10 <groupId>org.springframework.boot</groupId>
11 <artifactId>spring-boot-starter-parent</artifactId>
12 <version>2.3.4.RELEASE</version>
13 <relativePath /> <!-- lookup parent from repository -->
14 </parent>
15
16 <groupId>com.bie</groupId>
17 <artifactId>springboot-01</artifactId>
18 <version>0.0.1-SNAPSHOT</version>
19 <name>springboot-01</name>
20 <description>Demo project for Spring Boot</description>
21
22 <properties>
23 <java.version>1.8</java.version>
24 <maven-jar-plugin.version>3.1.1</maven-jar-plugin.version>
25 </properties>
26
27 <dependencies>
28 <dependency>
29 <groupId>org.springframework.boot</groupId>
30 <artifactId>spring-boot-starter-web</artifactId>
31 </dependency>
32
33 <dependency>
34 <groupId>org.springframework.boot</groupId>
35 <artifactId>spring-boot-starter-test</artifactId>
36 <scope>test</scope>
37 <exclusions>
38 <exclusion>
39 <groupId>org.junit.vintage</groupId>
40 <artifactId>junit-vintage-engine</artifactId>
41 </exclusion>
42 </exclusions>
43 </dependency>
44 <!-- https://mvnrepository.com/artifact/com.mchange/c3p0 -->
45 <dependency>
46 <groupId>com.mchange</groupId>
47 <artifactId>c3p0</artifactId>
48 <version>0.9.5.2</version>
49 </dependency>
50 <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
51 <dependency>
52 <groupId>mysql</groupId>
53 <artifactId>mysql-connector-java</artifactId>
54 <!-- <version>5.1.12</version> -->
55 </dependency>
56 <dependency>
57 <groupId>org.springframework.boot</groupId>
58 <artifactId>spring-boot-configuration-processor</artifactId>
59 <optional>true</optional>
60 </dependency>
61
62 <!-- 引入 Druid 数据源依赖：https://mvnrepository.com/artifact/com.alibaba/druid -->
63 <dependency>
64 <groupId>com.alibaba</groupId>
65 <artifactId>druid</artifactId>
66 <version>1.1.9</version>
67 </dependency>
68 </dependencies>
69
70 <build>
71 <plugins>
72 <plugin>
73 <groupId>org.springframework.boot</groupId>
74 <artifactId>spring-boot-maven-plugin</artifactId>
75 </plugin>
76 </plugins>
77 </build>
78
79 </project>修改application.yml配置文件，追加Druid的连接配置，如下所示：
代码语言：javascript复制 1 # 配置当前要使用的数据源的操作类型
2 spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
3 # 配置Mysql的驱动程序类
4 spring.datasource.driver-class-name=com.mysql.jdbc.Driver
5 # 数据库连接地址
6 spring.datasource.url=jdbc:mysql://127.0.0.1:3306/biehl
7 # 数据库用户名称
8 spring.datasource.username=root
9 # 数据库密码
10 spring.datasource.password=123456
11 # 进行数据库链接池的配置，数据库最小维持连接数
12 spring.datasource.dbcp2.min-idle=1
13 # 数据库初始化提供的连接数
14 spring.datasource.dbcp2.initial-size=1
15 # 数据库最大维持连接数
16 spring.datasource.dbcp2.max-total=1
17 # 等待连接获取的最大超时时间
18 spring.datasource.dbcp2.max-wait-millis=3000建立Druid数据源连接池配置类，此时设置的Bean名称为dataSource。也可以使用@Value手动一个一个将参数注入进来，然后设置，不过使用@ConfigurationProperties 绑定配置文件参数，此注解更加方便。
代码语言：javascript复制 1 package com.bie.config;
2
3 import javax.sql.DataSource;
4
5 import org.springframework.boot.context.properties.ConfigurationProperties;
6 import org.springframework.context.annotation.Bean;
7 import org.springframework.context.annotation.Configuration;
8
9 import com.alibaba.druid.pool.DruidDataSource;
10
11 @Configuration
12 public class DruidDataSourceConfiguration {
13
14 /**
15 * 注入bean
16 *
17 * @return
18 */
19 @Bean(name = "dataSource")
20 // 作用就是将全局配置文件中 前缀为 spring.datasource的属性值注入到
21 // com.alibaba.druid.pool.DruidDataSource 的同名参数中。
22 @ConfigurationProperties(prefix = "spring.datasource")
23 public DataSource dataSource() {
24 DruidDataSource datasource = new DruidDataSource();
25 return datasource;
26 }
27
28 }编写Junit测试类，测试当前DataSource配置是否正确。
代码语言：javascript复制 1 package com.bie;
2
3 import java.sql.Connection;
4 import java.sql.PreparedStatement;
5 import java.sql.ResultSet;
6 import java.sql.SQLException;
7
8 import javax.sql.DataSource;
9
10 import org.junit.jupiter.api.Test;
11 import org.junit.runner.RunWith;
12 import org.springframework.beans.factory.annotation.Autowired;
13 import org.springframework.boot.test.context.SpringBootTest;
14 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
15 import org.springframework.test.context.web.WebAppConfiguration;
16
17 @SpringBootTest(classes = Springboot01Application.class) // 定义要测试的Springboot类
18 @RunWith(SpringJUnit4ClassRunner.class) // 使用Junit进行测试
19 @WebAppConfiguration // 进行Web应用配置
20 class Springboot01ApplicationTests {
21
22 @Autowired
23 private DataSource dataSource; // 注入DataSource对象
24
25 @Test
26 void testConnection() throws SQLException {
27 // 获取连接
28 Connection connection = this.dataSource.getConnection();
29 System.out.println(connection);
30
31 String sql = "select * from user_info ";
32 PreparedStatement ps = connection.prepareStatement(sql);
33 ResultSet rs = ps.executeQuery();
34 UserInfo users = null;
35 if (rs.next()) {
36 users = new UserInfo();
37 // 从数据库中获取值设置到实体类的setter方法中
38 users.setUserId(rs.getInt("user_id"));
39 users.setUserAccount(rs.getString("user_account"));
40 users.setUserPw(rs.getString("user_pw"));
41 users.setUserNumber(rs.getString("user_number"));
42 users.setUserName(rs.getString("user_name"));
43 users.setUserAge(rs.getInt("user_age"));
44 users.setUserSex(rs.getString("user_sex"));
45 users.setUserMark(rs.getString("user_mark"));
46 users.setIsMoney(rs.getString("is_money"));
47 System.out.println(users.toString());
48 }
49 }
50
51 // 内部类
52 class UserInfo {
53 private Integer userId;// 用户编号
54 private String userAccount;// 用户账号
55 private String userPw;// 用户密码
56 private String userNumber;// 用户学号
57 private String userName;// 用户姓名
58 private Integer userAge;// 用户年龄
59 private String userSex;// 用户性别
60 private String userMark;// 用户标识，可以使用一张表，完成管理员和用户
61
62 private String isMoney;
63
64 public Integer getUserId() {
65 return userId;
66 }
67
68 public void setUserId(Integer userId) {
69 this.userId = userId;
70 }
71
72 public String getUserAccount() {
73 return userAccount;
74 }
75
76 public void setUserAccount(String userAccount) {
77 this.userAccount = userAccount;
78 }
79
80 public String getUserPw() {
81 return userPw;
82 }
83
84 public void setUserPw(String userPw) {
85 this.userPw = userPw;
86 }
87
88 public String getUserNumber() {
89 return userNumber;
90 }
91
92 public void setUserNumber(String userNumber) {
93 this.userNumber = userNumber;
94 }
95
96 public String getUserName() {
97 return userName;
98 }
99
100 public void setUserName(String userName) {
101 this.userName = userName;
102 }
103
104 public Integer getUserAge() {
105 return userAge;
106 }
107
108 public void setUserAge(Integer userAge) {
109 this.userAge = userAge;
110 }
111
112 public String getUserSex() {
113 return userSex;
114 }
115
116 public void setUserSex(String userSex) {
117 this.userSex = userSex;
118 }
119
120 public String getUserMark() {
121 return userMark;
122 }
123
124 public void setUserMark(String userMark) {
125 this.userMark = userMark;
126 }
127
128 public String getIsMoney() {
129 return isMoney;
130 }
131
132 public void setIsMoney(String isMoney) {
133 this.isMoney = isMoney;
134 }
135
136 @Override
137 public String toString() {
138 return "UserInfo [userId=" userId ", userAccount=" userAccount ", userPw=" userPw
139 ", userNumber=" userNumber ", userName=" userName ", userAge=" userAge ", userSex="
140 userSex ", userMark=" userMark ", isMoney=" isMoney "]";
141 }
142
143 }
144
145 }如果进行连接测试使用的ORM框架的话，需要导入相应ORM框架的依赖支持包。
