丢掉xml使用JavaConfig配置Spring

Spring JavaConfig

最近撸了一遍Spring action 4,发现里面讲的都不再使用xml文件来配置spring,全都采用Java代码来配置.

用Java代码配置的话,感觉要比xml更便于维护,而且用代码肯定比xml更爽嘛

下面来一步步用JavaConfig搭一个Spring工程

那在用xml配置的时候,项目都是从加载web.xml文件再扫描到各种spring-*.xml文件

那不用xml文件,项目从哪里启动呢?

那就要靠这个类了,AbstractAnnotationConfigDispatcherServletInitializer,这个就相当于web.xml啦,在这里面可以配置上下文,DispatcherServlet,过滤器等等bean;

首先咱先创建一个类SpittrWebAppInitialzer

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
package com.fireyao;
import org.springframework.web.filter.CharacterEncodingFilter;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;
import javax.servlet.Filter;
public class SpittrWebAppInitialzer extends AbstractAnnotationConfigDispatcherServletInitializer {
/**
* 配置root上下文,如Jpa数据源等等的配置
* @return
*/
@Override
protected Class<?>[] getRootConfigClasses() {
return new Class[]{RootConfig.class};
}
/**
* 配置dispatcher servlet
* @return
*/
@Override
protected Class<?>[] getServletConfigClasses() {
return new Class[]{WebConfig.class};
}
/**
* 将DispatcherServlet映射到 "/"
* 指定开始被servlet处理的url,配置从/开始
* @return
*/
@Override
protected String[] getServletMappings() {
return new String[]{"/"};
}
/**
* 这里注册的所有过滤器,都会映射到DispatcherServlet
* 就是说这里的过滤器过滤规则是 /*
* 所有的请求都会先到这里注册的过滤器中
*
* @return
*/
@Override
protected Filter[] getServletFilters() {
return new Filter[]{
new CharacterEncodingFilter("UTF-8", true)
};
}
}

SpittrWebAppInitialzer类里面加载了RootConfigWebConfig两个配置类,

再创建这两个类以及相关的配置(以下省略package和import)

RootConfig

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
/**
* 相当于applicationContext.xml
*/
@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(basePackages = {"com.fireyao.repository"},
entityManagerFactoryRef = "entityManagerFactory",
transactionManagerRef = "transactionManager")
@PropertySource(value = {"classpath:db.properties", "classpath:hibernate.properties", "classpath:app.properties"})
@ComponentScan(basePackages = "com.fireyao",
excludeFilters = {
@ComponentScan.Filter(
type = FilterType.ANNOTATION, value = EnableWebMvc.class
)})
@EnableAspectJAutoProxy(proxyTargetClass = true)
/**
* proxyTargetClass = true ==> 使用cglib代理
* proxyTargetClass = false(默认) ==> 使用JDK代理
*/
public class RootConfig {
@Value(value = "${db.driver:org.postgresql.Driver}")
private String DRIVERCLASSNAME;
@Value("${db.username}")
private String USERNAME;
@Value("${db.password}")
private String PASSWORD;
@Value("${db.jdbcURL}")
private String URL;
@Value("${hibernate.hbm2dll.create_namespaces}")
private String CREATE_NAMESPACES;
@Value("${hibernate.hbm2ddl.auto}")
private String HBM2DDL_AUTO;
@Value("${hibernate.show_sql}")
private String SHOW_SQL;
@Value("${hibernate.format_sql}")
private String FORMAT_SQL;
@Value("${hibernate.generate_statistics}")
private String GENERATE_STATISTICS;
/**
* 配置数据源
*/
@Bean(name = "dataSource")
public DruidDataSource dataSource() {
DruidDataSource dataSource = new DruidDataSource();
dataSource.setDriverClassName(DRIVERCLASSNAME);
dataSource.setUrl(URL);
dataSource.setUsername(USERNAME);
dataSource.setPassword(PASSWORD);
/* 配置初始化大小、最小、最大*/
dataSource.setInitialSize(5);
dataSource.setMinIdle(5);
dataSource.setMaxActive(20);
/* 配置获取连接等待超时的时间*/
dataSource.setMaxWait(30000);
/*配置间隔多久才进行一次检测,检测需要关闭的空闲连接,单位是毫秒*/
dataSource.setTimeBetweenEvictionRunsMillis(60000);
/*配置一个连接在池中最小生存的时间,单位是毫秒*/
dataSource.setMinEvictableIdleTimeMillis(300000);
/*申请连接的时候检测,如果空闲时间大于timeBetweenEvictionRunsMillis,执行validationQuery检测连接是否有效*/
dataSource.setTestWhileIdle(true);
dataSource.setValidationQuery("select 1");
return dataSource;
}
@Bean
public HibernateJpaVendorAdapter hibernateJpaVendorAdapter() {
return new HibernateJpaVendorAdapter();
}
@Bean(name = "entityManagerFactory")
public LocalContainerEntityManagerFactoryBean entityManagerFactory(DruidDataSource dataSource,HibernateJpaVendorAdapter hibernateJpaVendorAdapter) {
LocalContainerEntityManagerFactoryBean entityManagerFactory = new LocalContainerEntityManagerFactoryBean();
entityManagerFactory.setDataSource(dataSource);
entityManagerFactory.setJpaVendorAdapter(hibernateJpaVendorAdapter);
entityManagerFactory.setPackagesToScan("com.fireyao.domain");
/*指定JPA属性;如Hibernate中指定是否显示SQL的是否显示、方言等*/
Map<String, Object> jpaProp = new HashMap();
jpaProp.put("hibernate.dialect", new PostgisDialect());
jpaProp.put("hibernate.hbm2ddl.auto", HBM2DDL_AUTO);
jpaProp.put("hibernate.show_sql", SHOW_SQL);
jpaProp.put("hibernate.generate_statistics", GENERATE_STATISTICS);
jpaProp.put("hibernate.format_sql", FORMAT_SQL);
jpaProp.put("hibernate.hbm2dll.create_namespaces", CREATE_NAMESPACES);
entityManagerFactory.setJpaPropertyMap(jpaProp);
return entityManagerFactory;
}
/**
* 事务管理器
*
* @param entityManagerFactory
* @return
*/
@Bean(name = "transactionManager")
public JpaTransactionManager transactionManager(LocalContainerEntityManagerFactoryBean entityManagerFactory) {
return new JpaTransactionManager(entityManagerFactory.getObject());
}
}

WebConfig

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
/**
* 相当于springmvc-servlet.xml
*/
@Configuration
@EnableWebMvc//启用spring mvc
@ComponentScan(basePackages = "com.fireyao.controller") //启用组件扫描
public class WebConfig extends WebMvcConfigurerAdapter {
@Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter();
FastJsonConfig fastJsonConfig = new FastJsonConfig();
fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat);
//处理中文乱码问题
List<MediaType> fastMediaTypes = new ArrayList<>();
fastMediaTypes.add(MediaType.APPLICATION_JSON_UTF8);
fastConverter.setSupportedMediaTypes(fastMediaTypes);
fastConverter.setFastJsonConfig(fastJsonConfig);
converters.add(fastConverter);
}
/**
* Thymeleaf视图解析器
*
* @param springTemplateEngine
* @return
*/
@Bean
public ThymeleafViewResolver viewResolver(SpringTemplateEngine springTemplateEngine) {
ThymeleafViewResolver viewResolver = new ThymeleafViewResolver();
viewResolver.setTemplateEngine(springTemplateEngine);
viewResolver.setCharacterEncoding("utf-8");
return viewResolver;
}
/**
* 模版引擎
*
* @param iTemplateResolver
* @return
*/
@Bean
public SpringTemplateEngine templateEngine(ITemplateResolver iTemplateResolver) {
SpringTemplateEngine templateEngine = new SpringTemplateEngine();
templateEngine.setTemplateResolver(iTemplateResolver);
return templateEngine;
}
/**
* Thymeleaf3.0之后
* Thymeleaf模版解析器
*
* @return
*/
@Bean
public ITemplateResolver iTemplateResolver() {
SpringResourceTemplateResolver templateResolver = new SpringResourceTemplateResolver();
templateResolver.setTemplateMode("HTML5");
templateResolver.setPrefix("/WEB-INF/templates/");
templateResolver.setSuffix(".html");
templateResolver.setTemplateMode("HTML");
templateResolver.setCharacterEncoding("utf-8");
templateResolver.setCacheable(false);
return templateResolver;
}
/**
* Thymeleaf3.0之前
* Thymeleaf模版解析器
* @return
*/
/* @Bean
public TemplateResolver templateResolver() {
TemplateResolver resolver = new ServletContextTemplateResolver();
resolver.setPrefix("/WEB-INF/VIEWS/");
resolver.setSuffix(".html");
resolver.setTemplateMode("HTML5");
resolver.setCacheable(false);
return resolver;
}*/
/**
* 配置静态资源的处理
* 要求DispatcherServlet将对静态资源的请求转发到Servlet容器中默认的Servlet上
* 而不是使用DispatcherServlet本身来处理此类请求。
*
* @param configurer
*/
@Override
public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
configurer.enable();
}
/**
* 配置视图解析器
* ==> JSP视图
*
* @return
*/
/*@Bean
public ViewResolver viewResolver() {
InternalResourceViewResolver resolver = new InternalResourceViewResolver();
resolver.setPrefix("/WEB-INF/views/");
resolver.setSuffix(".jsp");
resolver.setExposeContextBeansAsAttributes(true);
return resolver;
}*/
}

@Configuration 标注为配置类

@EnableTransactionManagement注解开启注解式事务的支持。

@EnableJpaRepositories注解开启对Spring Data JPA Repostory的支持

@PropertySource 扫面db.properties等配置文件,可以用@Value注解取到properties中的值

@ComponentScan 配置扫描类包 相当于<context:component-scan base-package="com.fireyao"/>

@EnableAspectJAutoProxy 表示开启AOP代理自动配置

@EnableAspectJAutoProxy中proxyTargetClass属性
​ proxyTargetClass = true ==> 使用cglib代理
​ proxyTargetClass = false(默认) ==> 使用JDK代理

那spring最基本的JavaConfig就这样了.

是不是看上去很舒服,果然还是要用Java代码才爽.

maven依赖就不贴出来了.

附上源码地址 FireYao/springAction4