Java Charseting

override-default-charset.sh

Can We Override the Default Charset?

-Dfile.encoding="UTF-8"
-Dsun.jnu.encoding="UTF-8"

java -Dfile.encoding=utf-8 -jar target\application.jar

• CharacterEncodingFilter for POST requests
• URIEncoding (or useBodyEncodingForURI="true") for GET requests

Server Page Encoding
JSPs :

<%@page pageEncoding="UTF-8" contentType="text/html; charset=UTF-8"%>
<%@ page language="java" pageEncoding="UTF-8"%>
<%@ page contentType="text/html;charset=UTF-8" %>

XML :
<jsp:directive.page contentType="text/html; charset=UTF-8" />

HTML Page Encoding

<meta http-equiv='Content-Type' content='text/html; charset=UTF-8' />

MySQL Server Configuration

my.cnf

[client]
default-character-set = utf8mb4

[mysql]
default-character-set = utf8mb4

[mysqld]
character-set-client-handshake = FALSE
character-set-server = utf8mb4
collation-server = utf8mb4_unicode_ci

MySQL Database Configuration

ALTER DATABASE database_name CHARACTER SET = utf8mb4 
    COLLATE = utf8mb4_unicode_ci;

ALTER TABLE table_name CONVERT TO 
    CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

ALTER TABLE table_name CHANGE column_name column_name 
    VARCHAR(69) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

JDBC Connection URL
jdbc:mysql://localhost:3306/?useUnicode=yes;characterEncoding=UTF-8

<Resource name="jdbc/AppDB" 
        auth="Container"
        type="javax.sql.DataSource"
        maxActive="20" maxIdle="10" maxWait="10000"
        username="foo"
        password="bar"
        driverClassName="com.mysql.jdbc.Driver" url="jdbc:mysql://localhost:3306/      ID_development?useEncoding=true&amp;characterEncoding=UTF-8"
    />

Maven POM Configuration :
pom.xml

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    ...
</properties>

Gradle Configuration :

compileJava.options.encoding = 'UTF-8'

Other Render View Config

@Bean
public StringHttpMessageConverter stringHttpMessageConverter() {
    return new StringHttpMessageConverter(Charset.forName("UTF-8"));
}

Force UTF-8 encoding in Spring MVC returning String

@RequestMapping

produces = MediaType.APPLICATION_JSON_VALUE + "; charset=utf-8"

In addition to Benjamin's answer - in case if you are using Spring Security, placing the CharacterEncodingFilter in web.xml might not always work. In this case you need to create a custom filter and add it to the filter chain as the first filter. To make sure it's the first filter in the chain, you need to add it before ChannelProcessingFilter, using addFilterBefore in your WebSecurityConfigurerAdapter :

@Configuration
@EnableWebSecurity 
public class SecurityConfig extends WebSecurityConfigurerAdapter {


    @Override
    protected void configure(HttpSecurity http) throws Exception {

        //add your custom encoding filter as the first filter in the chain
        http.addFilterBefore(new EncodingFilter(), ChannelProcessingFilter.class);

        http.authorizeRequests()
            .and()
            // your code here ...
    }
}

public class EncodingFilter extends GenericFilterBean {

    @Override
    public void doFilter(
            ServletRequest request, 
            ServletResponse response,
            FilterChain chain) throws IOException, ServletException {

        request.setCharacterEncoding("UTF-8");
        response.setCharacterEncoding("UTF-8");

        chain.doFilter(request, response);
    }
}

[Spring MVC Java config] (https://stackoverflow.com/questions/22225040/spring-mvc-java-config)

@Override
      protected Filter[] getServletFilters() {

        CharacterEncodingFilter characterEncodingFilter = new CharacterEncodingFilter();
        characterEncodingFilter.setEncoding("UTF-8");
        return new Filter[] { characterEncodingFilter};
      }

web.xml

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
                      http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
  version="4.0">
  <request-character-encoding>UTF-8</request-character-encoding>

<jsp-config>
    <jsp-property-group>
        <url-pattern>*.jsp</url-pattern>
        <page-encoding>UTF-8</page-encoding>
    </jsp-property-group>
</jsp-config>

Or in Java config :
servletContext.setRequestCharacterEncoding("UTF-8");

catalina.sh / catalina.bat - added following

set JAVA_OPTS=--Xms256m -Xmx1024m -Xss268k -server -XX:MaxPermSize=256m -XX:-UseGCOverheadLimit -Djava.awt.headless=true -Djavax.servlet.request.encoding=UTF-8 -Dfile.encoding=UTF-8

set CATALINA_OPTS=-Dfile.encoding="UTF-8"

<bean id="templateResolver" class="org.thymeleaf.templateresolver.ServletContextTemplateResolver">
    ...
    <property name="characterEncoding" value="UTF-8"/>
    ...
</bean>

<bean class="org.thymeleaf.spring4.view.ThymeleafViewResolver">
    ...
    <property name="characterEncoding" value="UTF-8"/>
    ...
</bean>

In SpringConfig

public class SpringConfig implements WebMvcConfigurer {

    private final ApplicationContext applicationContext;

    @Autowired
    public SpringConfig(ApplicationContext applicationContext) {
        this.applicationContext = applicationContext;
    }

    @Bean
    public SpringResourceTemplateResolver templateResolver() {
        SpringResourceTemplateResolver templateResolver = new SpringResourceTemplateResolver();
        templateResolver.setApplicationContext(applicationContext);
        templateResolver.setPrefix("/WEB-INF/views/");
        templateResolver.setSuffix(".html");
        templateResolver.setCharacterEncoding("UTF-8");
        return templateResolver;
    }

    @Bean
    public SpringTemplateEngine templateEngine() {
        SpringTemplateEngine templateEngine = new SpringTemplateEngine();
        templateEngine.setTemplateResolver(templateResolver());
        templateEngine.setEnableSpringELCompiler(true);
        return templateEngine;
    }

    @Override
    public void configureViewResolvers(ViewResolverRegistry registry) {
        ThymeleafViewResolver resolver = new ThymeleafViewResolver();
        resolver.setTemplateEngine(templateEngine());
        resolver.setCharacterEncoding("UTF-8");
        registry.viewResolver(resolver);
    }
}

In ServletInitializer

public class MySpringMvcDispatcherServletInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
    @Override
    protected Class<?>[] getRootConfigClasses() {
        return null;
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class[]{SpringConfig.class};
    }

    @Override
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }

    @Override
    protected Filter[] getServletFilters() {
        CharacterEncodingFilter filter = new CharacterEncodingFilter();
        filter.setEncoding("UTF-8");
        filter.setForceEncoding(true);
        return new Filter[] { filter };
    }
}

application.properties

spring.thymeleaf.enabled=true
spring.thymeleaf.encoding=UTF-8