@JsonSerialize

先看下jackson的@JsonSerialize注解。

@JsonSerialize是jackson提供自定義序列化方法的注解，它有個using 屬性，指定自定義序列化的執(zhí)行類；

例如：
先自定義一個序列化類

public class OptimizedBooleanSerializer extends JsonSerializer<Boolean> {

    @Override
    public void serialize(Boolean aBoolean, JsonGenerator jsonGenerator, 
        SerializerProvider serializerProvider) 
    throws IOException, JsonProcessingException {

        if(aBoolean){
            jsonGenerator.writeNumber(1);
        } else {
            jsonGenerator.writeNumber(0);
        }
    }
}

@JsonSerialize注解的Java類示例

public class PersonVo {

    public long   personId = 0;
    public String name ="John";

    @JsonSerialize(using = OptimizedBooleanSerializer.class)
    public boolean enabled = false;
}

我們知道，springMVC是通過jackson這個序列化框架，當(dāng)響應(yīng)頭的Content-Type是application/json;charset=UTF-8時，對返回的vo轉(zhuǎn)換為json對象；所以，利用jackson的注解，這樣就可以實現(xiàn)脫敏，下面我們對這個注解做一層封裝。

升級

1.自定義序列化類，每當(dāng)有需要脫敏的字段，例如，人名，郵箱，手機(jī)號等等，我們就創(chuàng)建一個這樣的類，主要是制定一種脫敏的規(guī)則。

public class EmailDesensitization extends JsonSerializer<String> {

    /**
     * 郵箱正則(半匹配)
     */
    private static final Pattern DEFAULT_PATTERN = Pattern.compile("([A-Za-z0-9_\\-.])+@([A-Za-z0-9_\\-.])+\\.([A-Za-z]{2,4})");

    @Override
    public void serialize(String value, JsonGenerator gen, SerializerProvider serializers) throws IOException {
        Matcher matcher = DEFAULT_PATTERN.matcher(value);
        while (matcher.find()) {
            String group = matcher.group();
            int l = group.lastIndexOf("@");
            value = value.replace(group, group.substring(0,2) + Symbol.getSymbol(l - 2, Symbol.STAR) + group.substring(l));
        }

        gen.writeString(value);
    }

}

2.定義脫敏注解
@JacksonAnnotationsInside 表示將注解捆綁；當(dāng)我們在字段注解@EmailDesensitize ，等價于@JsonSerialize(using = EmailDesensitization.class)；

@Target({ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
@JacksonAnnotationsInside
@JsonSerialize(using = EmailDesensitization.class)
@Documented
public @interface EmailDesensitize {
}

Symbol類

public class Symbol {


    /**
     * '*'脫敏符
     */
    public static final String STAR = "*";

    private Symbol() {

    }

    /**
     * 獲取符號
     *
     * @param number 符號個數(shù)
     * @param symbol 符號
     */
    public static String getSymbol(int number, String symbol) {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < number; i++) {
            sb.append(symbol);
        }
        return sb.toString();
    }
}

3.vo字段加注解

public class PersonVo {

    private String name;

    @JsonProperty("someEmail")
    @EmailDesensitize
    private String email;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }
}

4.測試

@RestController
public class TestController {

    @ResponseBody
    @GetMapping("/getPerson")
    public PersonVo getPerson() {
        PersonVo vo = new PersonVo();
        vo.setName("強(qiáng)強(qiáng)");
        vo.setEmail("13355782547@qq.com");
        return vo;
    }

}

5.結(jié)果

{"name":"強(qiáng)強(qiáng)","someEmail":"13********@qq.com"}