http://netty.io/netty-all/: Netty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers and clients. (The Netty Project) 
public class io.netty.handler.codec.http.QueryStringEncoder
  minor version: 0
  major version: 59
  flags: flags: (0x0021) ACC_PUBLIC, ACC_SUPER
  this_class: io.netty.handler.codec.http.QueryStringEncoder
  super_class: java.lang.Object
{
  private final java.lang.String charsetName;
    descriptor: Ljava/lang/String;
    flags: (0x0012) ACC_PRIVATE, ACC_FINAL

  private final java.lang.StringBuilder uriBuilder;
    descriptor: Ljava/lang/StringBuilder;
    flags: (0x0012) ACC_PRIVATE, ACC_FINAL

  private boolean hasParams;
    descriptor: Z
    flags: (0x0002) ACC_PRIVATE

  public void <init>(java.lang.String);
    descriptor: (Ljava/lang/String;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=2, args_size=2
        start local 0 // io.netty.handler.codec.http.QueryStringEncoder this
        start local 1 // java.lang.String uri
         0: .line 49
            aload 0 /* this */
            aload 1 /* uri */
            getstatic io.netty.handler.codec.http.HttpConstants.DEFAULT_CHARSET:Ljava/nio/charset/Charset;
            invokespecial io.netty.handler.codec.http.QueryStringEncoder.<init>:(Ljava/lang/String;Ljava/nio/charset/Charset;)V
         1: .line 50
            return
        end local 1 // java.lang.String uri
        end local 0 // io.netty.handler.codec.http.QueryStringEncoder this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lio/netty/handler/codec/http/QueryStringEncoder;
            0    2     1   uri  Ljava/lang/String;
    MethodParameters:
      Name  Flags
      uri   

  public void <init>(java.lang.String, java.nio.charset.Charset);
    descriptor: (Ljava/lang/String;Ljava/nio/charset/Charset;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=4, locals=3, args_size=3
        start local 0 // io.netty.handler.codec.http.QueryStringEncoder this
        start local 1 // java.lang.String uri
        start local 2 // java.nio.charset.Charset charset
         0: .line 56
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 57
            aload 0 /* this */
            new java.lang.StringBuilder
            dup
            aload 1 /* uri */
            invokespecial java.lang.StringBuilder.<init>:(Ljava/lang/String;)V
            putfield io.netty.handler.codec.http.QueryStringEncoder.uriBuilder:Ljava/lang/StringBuilder;
         2: .line 58
            aload 0 /* this */
            aload 2 /* charset */
            invokevirtual java.nio.charset.Charset.name:()Ljava/lang/String;
            putfield io.netty.handler.codec.http.QueryStringEncoder.charsetName:Ljava/lang/String;
         3: .line 59
            return
        end local 2 // java.nio.charset.Charset charset
        end local 1 // java.lang.String uri
        end local 0 // io.netty.handler.codec.http.QueryStringEncoder this
      LocalVariableTable:
        Start  End  Slot     Name  Signature
            0    4     0     this  Lio/netty/handler/codec/http/QueryStringEncoder;
            0    4     1      uri  Ljava/lang/String;
            0    4     2  charset  Ljava/nio/charset/Charset;
    MethodParameters:
         Name  Flags
      uri      
      charset  

  public void addParam(java.lang.String, java.lang.String);
    descriptor: (Ljava/lang/String;Ljava/lang/String;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=3, args_size=3
        start local 0 // io.netty.handler.codec.http.QueryStringEncoder this
        start local 1 // java.lang.String name
        start local 2 // java.lang.String value
         0: .line 65
            aload 1 /* name */
            ldc "name"
            invokestatic io.netty.util.internal.ObjectUtil.checkNotNull:(Ljava/lang/Object;Ljava/lang/String;)Ljava/lang/Object;
            pop
         1: .line 66
            aload 0 /* this */
            getfield io.netty.handler.codec.http.QueryStringEncoder.hasParams:Z
            ifeq 4
         2: .line 67
            aload 0 /* this */
            getfield io.netty.handler.codec.http.QueryStringEncoder.uriBuilder:Ljava/lang/StringBuilder;
            bipush 38
            invokevirtual java.lang.StringBuilder.append:(C)Ljava/lang/StringBuilder;
            pop
         3: .line 68
            goto 6
         4: .line 69
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            getfield io.netty.handler.codec.http.QueryStringEncoder.uriBuilder:Ljava/lang/StringBuilder;
            bipush 63
            invokevirtual java.lang.StringBuilder.append:(C)Ljava/lang/StringBuilder;
            pop
         5: .line 70
            aload 0 /* this */
            iconst_1
            putfield io.netty.handler.codec.http.QueryStringEncoder.hasParams:Z
         6: .line 72
      StackMap locals:
      StackMap stack:
            aload 1 /* name */
            aload 0 /* this */
            getfield io.netty.handler.codec.http.QueryStringEncoder.charsetName:Ljava/lang/String;
            aload 0 /* this */
            getfield io.netty.handler.codec.http.QueryStringEncoder.uriBuilder:Ljava/lang/StringBuilder;
            invokestatic io.netty.handler.codec.http.QueryStringEncoder.appendComponent:(Ljava/lang/String;Ljava/lang/String;Ljava/lang/StringBuilder;)V
         7: .line 73
            aload 2 /* value */
            ifnull 10
         8: .line 74
            aload 0 /* this */
            getfield io.netty.handler.codec.http.QueryStringEncoder.uriBuilder:Ljava/lang/StringBuilder;
            bipush 61
            invokevirtual java.lang.StringBuilder.append:(C)Ljava/lang/StringBuilder;
            pop
         9: .line 75
            aload 2 /* value */
            aload 0 /* this */
            getfield io.netty.handler.codec.http.QueryStringEncoder.charsetName:Ljava/lang/String;
            aload 0 /* this */
            getfield io.netty.handler.codec.http.QueryStringEncoder.uriBuilder:Ljava/lang/StringBuilder;
            invokestatic io.netty.handler.codec.http.QueryStringEncoder.appendComponent:(Ljava/lang/String;Ljava/lang/String;Ljava/lang/StringBuilder;)V
        10: .line 77
      StackMap locals:
      StackMap stack:
            return
        end local 2 // java.lang.String value
        end local 1 // java.lang.String name
        end local 0 // io.netty.handler.codec.http.QueryStringEncoder this
      LocalVariableTable:
        Start  End  Slot   Name  Signature
            0   11     0   this  Lio/netty/handler/codec/http/QueryStringEncoder;
            0   11     1   name  Ljava/lang/String;
            0   11     2  value  Ljava/lang/String;
    MethodParameters:
       Name  Flags
      name   
      value  

  public java.net.URI toUri();
    descriptor: ()Ljava/net/URI;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=1, args_size=1
        start local 0 // io.netty.handler.codec.http.QueryStringEncoder this
         0: .line 85
            new java.net.URI
            dup
            aload 0 /* this */
            invokevirtual io.netty.handler.codec.http.QueryStringEncoder.toString:()Ljava/lang/String;
            invokespecial java.net.URI.<init>:(Ljava/lang/String;)V
            areturn
        end local 0 // io.netty.handler.codec.http.QueryStringEncoder this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lio/netty/handler/codec/http/QueryStringEncoder;
    Exceptions:
      throws java.net.URISyntaxException

  public java.lang.String toString();
    descriptor: ()Ljava/lang/String;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // io.netty.handler.codec.http.QueryStringEncoder this
         0: .line 95
            aload 0 /* this */
            getfield io.netty.handler.codec.http.QueryStringEncoder.uriBuilder:Ljava/lang/StringBuilder;
            invokevirtual java.lang.StringBuilder.toString:()Ljava/lang/String;
            areturn
        end local 0 // io.netty.handler.codec.http.QueryStringEncoder this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lio/netty/handler/codec/http/QueryStringEncoder;

  private static void appendComponent(java.lang.String, java.lang.String, java.lang.StringBuilder);
    descriptor: (Ljava/lang/String;Ljava/lang/String;Ljava/lang/StringBuilder;)V
    flags: (0x000a) ACC_PRIVATE, ACC_STATIC
    Code:
      stack=4, locals=6, args_size=3
        start local 0 // java.lang.String s
        start local 1 // java.lang.String charset
        start local 2 // java.lang.StringBuilder sb
         0: .line 100
            aload 0 /* s */
            aload 1 /* charset */
            invokestatic java.net.URLEncoder.encode:(Ljava/lang/String;Ljava/lang/String;)Ljava/lang/String;
            astore 0 /* s */
         1: .line 101
            goto 4
      StackMap locals:
      StackMap stack: java.io.UnsupportedEncodingException
         2: pop
         3: .line 102
            new java.nio.charset.UnsupportedCharsetException
            dup
            aload 1 /* charset */
            invokespecial java.nio.charset.UnsupportedCharsetException.<init>:(Ljava/lang/String;)V
            athrow
         4: .line 105
      StackMap locals:
      StackMap stack:
            aload 0 /* s */
            bipush 43
            invokevirtual java.lang.String.indexOf:(I)I
            istore 3 /* idx */
        start local 3 // int idx
         5: .line 106
            iload 3 /* idx */
            iconst_m1
            if_icmpne 8
         6: .line 107
            aload 2 /* sb */
            aload 0 /* s */
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
            pop
         7: .line 108
            return
         8: .line 110
      StackMap locals: int
      StackMap stack:
            aload 2 /* sb */
            aload 0 /* s */
            iconst_0
            iload 3 /* idx */
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/CharSequence;II)Ljava/lang/StringBuilder;
            ldc "%20"
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
            pop
         9: .line 111
            aload 0 /* s */
            invokevirtual java.lang.String.length:()I
            istore 4 /* size */
        start local 4 // int size
        10: .line 112
            iinc 3 /* idx */ 1
        11: .line 113
            goto 18
        12: .line 114
      StackMap locals: int
      StackMap stack:
            aload 0 /* s */
            iload 3 /* idx */
            invokevirtual java.lang.String.charAt:(I)C
            istore 5 /* c */
        start local 5 // char c
        13: .line 115
            iload 5 /* c */
            bipush 43
            if_icmpeq 16
        14: .line 116
            aload 2 /* sb */
            iload 5 /* c */
            invokevirtual java.lang.StringBuilder.append:(C)Ljava/lang/StringBuilder;
            pop
        15: .line 117
            goto 17
        16: .line 118
      StackMap locals: int
      StackMap stack:
            aload 2 /* sb */
            ldc "%20"
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
            pop
        end local 5 // char c
        17: .line 113
      StackMap locals:
      StackMap stack:
            iinc 3 /* idx */ 1
      StackMap locals:
      StackMap stack:
        18: iload 3 /* idx */
            iload 4 /* size */
            if_icmplt 12
        19: .line 121
            return
        end local 4 // int size
        end local 3 // int idx
        end local 2 // java.lang.StringBuilder sb
        end local 1 // java.lang.String charset
        end local 0 // java.lang.String s
      LocalVariableTable:
        Start  End  Slot     Name  Signature
            0   20     0        s  Ljava/lang/String;
            0   20     1  charset  Ljava/lang/String;
            0   20     2       sb  Ljava/lang/StringBuilder;
            5   20     3      idx  I
           10   20     4     size  I
           13   17     5        c  C
      Exception table:
        from    to  target  type
           0     1       2  Class java.io.UnsupportedEncodingException
    MethodParameters:
         Name  Flags
      s        
      charset  
      sb       
}
SourceFile: "QueryStringEncoder.java"