使用spring連接mysql數據庫出錯

使用spring連接mysql數據庫出錯

最近在學習spring框架，但是在學到JdbcTemplate時連接數據庫一直報錯，百度谷歌各種查找都能沒有解決問題，簡直要癲狂，報錯信息如下：

org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: Connections could not be acquired from the underlying database!
	at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:80)
	at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:390)
	at org.springframework.jdbc.core.JdbcTemplate.update(JdbcTemplate.java:534)
	at cn.itcast.a_jdbctemplate.Demo.fun1(Demo.java:38)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
	at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
	at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:254)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:89)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
	at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:193)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
Caused by: java.sql.SQLException: Connections could not be acquired from the underlying database!
	at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106)
	at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:529)
	at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128)
	at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:111)
	at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:77)
	... 32 more
Caused by: com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource from its primary factory or source.
	at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1319)
	at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:557)
	at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:477)
	at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:525)
	... 35 more

最後的原因是我使用的數據庫是Mysql8,太新了，相對以前我使用的Mysql5需要在url參數上添加一些參數，（吐血。。。。。），調了三天，期間換了IDE，MySQL等等，最後解決方法是把url換成這樣：

jdbc:mysql:///spring?useSSL=false&serverTimezone=UTC&characterEncoding=utf8

重點是設置：useSSL=false

還有一點，最新的mysql驅動類應當是：com.mysql.cj.jdbc.Driver，以前的 com.mysql.cj.jdbc.Driver提示被廢棄了。

最後完整的測試代碼供君借鑑：

　@Test
public void test05() throws Exception {
	// 創建數據源
	ComboPooledDataSource dataSource = new ComboPooledDataSource();
	//設置連接相關參數
	dataSource.setDriverClass("com.mysql.cj.jdbc.Driver");
	dataSource.setJdbcUrl("jdbc:mysql:///spring?useSSL=false&serverTimezone=UTC&characterEncoding=utf8");
	dataSource.setUser("root");
	dataSource.setPassword("123456");
	//創建模板對象
	JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
	//測試相關代碼是否執行
	System.out.println("Hello");
	String sql = "insert into jdbc_template values(null,'Nick') ";
	jdbcTemplate.update(sql);
	System.out.println("!!!!!!!!!!!OK!!!!!!!!!!!!!!!!");
}

數據庫創建代碼：

CREATE DATABASE spring;
USE spring;

CREATE TABLE jdbc_template(
id INT AUTO_INCREMENT PRIMARY KEY,
NAME VARCHAR(255) NOT NULL
);

INSERT INTO jdbc_template VALUES(NULL,'rose') ;

SELECT * FROM jdbc_template;